On-board Intrusion Detection & Prevention

Utilize on-board intrusion detection/prevention system that monitors the mission critical components or systems and audit/logs actions. The IDS/IPS should have the capability to respond to threats (initial access, execution, persistence, evasion, exfiltration, etc.) and it should address signature-based attacks along with dynamic never-before seen attacks using machine learning/adaptive technologies. The IDS/IPS must integrate with traditional fault management to provide a wholistic approach to faults on-board the spacecraft. Spacecraft should select and execute safe countermeasures against cyber-attacks. These countermeasures are a ready supply of options to triage against the specific types of attack and mission priorities. Minimally, the response should ensure vehicle safety and continued operations. Ideally, the goal is to trap the threat, convince the threat that it is successful, and trace and track the attacker — with or without ground support. This would support successful attribution and evolving countermeasures to mitigate the threat in the future. “Safe countermeasures” are those that are compatible with the system’s fault management system to avoid unintended effects or fratricide on the system.

Sources

https://attack.mitre.org/mitigations/M1031/

NIST Rev5 Controls

D3FEND Techniques

D3FEND Artifacts

ISO 27001

NASA Best Practice Guide

ESA Space Shield Mitigation

Related MITRE EMB3D Mitigations

Related CSF 2.0

Related BSI Security Measures

BM7
BM8
BM14
BM19
BM35
BM47
BM48
BM59

ID: CM0032

Tier: I

Onboard SV CM

Created: 2022/10/19

Last Modified: 2025/04/15

Techniques Addressed by Countermeasure

ID		Name	Description
IA-0003		Crosslink via Compromised Neighbor	Where spacecraft exchange data over inter-satellite links (RF or optical), a compromise on one vehicle can become a bridgehead to others. Threat actors exploit crosslink trust: shared routing, time distribution, service discovery, or gateway functions that forward commands and data between vehicles and ground. With knowledge of crosslink framing, addressing, and authentication semantics, an adversary can craft traffic that appears to originate from a trusted neighbor, injecting control messages, malformed service advertisements, or payload tasking that propagates across the mesh. In tightly coupled constellations, crosslinks may terminate on gateways that also touch the C&DH or payload buses, providing additional pivot opportunities. Because crosslink traffic is expected and often high volume, attacker activity can be timed to blend with synchronization intervals, ranging exchanges, or scheduled data relays.
IA-0006		Compromise Hosted Payload	Adversaries target hosted payloads as an alternate doorway into the host spacecraft. Hosted payloads often expose their own command sets, file services, and telemetry paths, sometimes via the host’s TT&C chain, sometimes through a parallel ground infrastructure under different operational control. Initial access arises when an attacker obtains the ability to issue payload commands, upload files, or alter memory/register state on the hosted unit. Because data and control must traverse an interface to the host bus (power, time, housekeeping, data routing, gateway processors), the payload–host boundary can also carry management functions: mode transitions, table loads, firmware updates, and cross-strapped links that appear only in maintenance or contingency modes. With knowledge of the interface specification and command dictionaries, a threat actor can activate rarely used modes, inject crafted data products, or trigger gateway behaviors that extend influence beyond the payload itself. In multi-tenant or commercial hosting arrangements, differences in keying, procedures, or scheduling between the payload operator and the bus operator provide additional opportunity for a first foothold that looks like routine payload commanding.
IA-0007		Compromise Ground System	Compromising the ground segment gives an adversary the most direct path to first execution against a spacecraft. Ground systems encompass operator workstations and mission control mission control software, scheduling/orchestration services, front-end processors and modems, antenna control, key-loading tools and HSMs, data gateways (SLE/CSP), identity providers, and cloud-hosted mission services. Once inside, a threat actor can prepare on-orbit updates, craft and queue valid telecommands, replay captured traffic within acceptance windows, or manipulate authentication material and counters to pass checks. The same foothold enables deep reconnaissance: enumerating mission networks and enclaves, discovering which satellites are operated from a site, mapping logical topology between MOC and stations, identifying in-band “birds” reachable from a given aperture, and learning pass plans, dictionaries, and automation hooks. From there, initial access to the spacecraft is a matter of timing and presentation, injecting commands, procedures, or update packages that align with expected operations so the first execution event appears indistinguishable from normal activity.
	.01	Compromise On-Orbit Update	Adversaries may target the pipeline that produces and transmits updates to an on-orbit vehicle. Manipulation points include source repositories and configuration tables, build and packaging steps that generate images or differential patches, staging areas on ground servers, update metadata (versions, counters, manifests), and the transmission process itself. Spacecraft updates span flight software patches, FPGA bitstreams, bootloader or device firmware loads, and operational data products such as command tables, ephemerides, and calibration files, each with distinct formats, framing, and acceptance rules. An attacker positioned in the ground system can substitute or modify an artifact, alter its timing and timetags to match pass windows, and queue it through the same procedures operators use for nominal maintenance. Activation can be immediate or deferred: implants may lie dormant until a specific mode, safing entry, or table index is referenced.
	.02	Malicious Commanding via Valid GS	Adversaries may use a compromised, mission-owned ground system to transmit legitimate-looking commands to the target spacecraft. Because the ground equipment is already configured for the mission, correct waveforms, framing, dictionaries, and scheduling, the attacker’s traffic blends with routine operations. Initial access unfolds by inserting commands or procedures into existing timelines, modifying rate/size limits or command queues, or invoking maintenance dictionaries and rapid-response workflows that accept broader command sets. Pre-positioned scripts can chain actions across multiple passes and stations, while telemetry routing provides immediate feedback to refine follow-on steps. Exfiltration can be embedded in standard downlink channels or forwarded through gateways as ordinary mission data. The distinguishing feature is that command origin appears valid, transmitted from approved apertures using expected parameters, so the first execution event is not a protocol anomaly but a misuse of legitimate command authority obtained through the compromised ground system.
IA-0008		Rogue External Entity	Adversaries obtain a foothold by interacting with the spacecraft from platforms outside the authorized ground architecture. A “rogue external entity” is any actor-controlled transmitter or node, ground, maritime, airborne, or space-based, that can radiate or exchange traffic using mission-compatible waveforms, framing, or crosslink protocols. The technique exploits the fact that many vehicles must remain commandable and discoverable over wide areas and across multiple modalities. Using public ephemerides, pass predictions, and knowledge of acquisition procedures, the actor times transmissions to line-of-sight windows, handovers, or maintenance periods. Initial access stems from presenting traffic that the spacecraft will parse or prioritize: syntactically valid telecommands, crafted ranging/acquisition exchanges, crosslink service advertisements, or payload/user-channel messages that bridge into the command/data path.
	.01	Rogue Ground Station	Adversaries may field their own ground system, transportable or fixed, to transmit and receive mission-compatible signals. A typical setup couples steerable apertures and GPS-disciplined timing with SDR/modems configured for the target’s bands, modulation/coding, framing, and beacon structure. Using pass schedules and Doppler/polarization predictions, the actor crafts over-the-air traffic that appears valid at the RF and protocol layers.
	.02	Rogue Spacecraft	Adversaries may employ their own satellite or hosted payload to achieve proximity and a privileged RF geometry. After phasing into the appropriate plane or drift orbit, the rogue vehicle operates as a local peer: emitting narrow-beam or crosslink-compatible signals, relaying user-channel traffic that the target will honor, or advertising services that appear to originate from a trusted neighbor. Close range reduces path loss and allows highly selective interactions, e.g., targeted spoofing of acquisition exchanges, presentation of crafted routing/time distribution messages, or injection of payload tasking that rides established inter-satellite protocols. The rogue platform can also perform spectrum and protocol reconnaissance in situ, refining message formats and timing before attempting first execution.
IA-0010		Unauthorized Access During Safe-Mode	Adversaries time their first execution to coincide with safe-mode, when the vehicle prioritizes survival and recovery. In many designs, safe-mode reconfigures attitude, reduces payload activity, lowers data rates, and enables contingency dictionaries or maintenance procedures that are dormant in nominal operations. Authentication, rate/size limits, command interlocks, and anti-replay handling may differ; some implementations reset counters, relax timetag screening, accept broader command sets, or activate alternate receivers and beacons to improve commandability. Ground behavior also shifts: extended passes, emergency scheduling, and atypical station use create predictable windows. An attacker who understands these patterns can present syntactically valid traffic that aligns with safe-mode expectations, maintenance loads, recovery scripts, table edits, or reboot/patch sequences, so the first accepted action appears consistent with fault recovery rather than intrusion.
IA-0011		Auxiliary Device Compromise	Adversaries abuse peripherals and removable media that the spacecraft (or its support equipment) ingests during development, I&T, or on-orbit operations. Small satellites and hosted payloads frequently expose standard interfaces, USB, UART, Ethernet, SpaceWire, CAN, or mount removable storage for loading ephemerides, tables, configuration bundles, or firmware. A tainted device can masquerade as a trusted class (mass-storage, CDC/HID) or present crafted files that trigger auto-ingest workflows, file watchers, or maintenance utilities. Malware may be staged by modifying the peripheral’s firmware, seeding the images written by lab formatting tools, or swapping media during handling. Once connected, the device can deliver binaries, scripts, or malformed data products that execute under existing procedures. Because these interactions often occur during hurried timelines (checkouts, rehearsals, contingency maintenance), the initial execution blends with legitimate peripheral use while traversing a path already privileged to reach flight software or controllers.
IA-0013		Compromise Host Spacecraft	The inverse of "IA-0006: Compromise Hosted Payload", this technique describes adversaries that are targeting a hosted payload, the host space vehicle (SV) can serve as an initial access vector to compromise the payload through vulnerabilities in the SV's onboard systems, communication interfaces, or software. If the SV's command and control systems are exploited, an attacker could gain unauthorized access to the vehicle's internal network. Once inside, the attacker may laterally move to the hosted payload, particularly if it shares data buses, processors, or communication links with the vehicle.
EX-0001		Replay	Replay is the re-transmission of previously captured traffic, over RF links, crosslinks, or internal buses, to elicit the same processing and effects a second time. Adversaries first observe and record authentic exchanges (telecommands, ranging/acquisition frames, housekeeping telemetry acknowledgments, bus messages), then resend them within acceptance conditions that the system recognizes, matching link geometry, timetags, counters, or mode states. The aim can be functional (re-triggering an action such as a mode change), observational (fingerprinting how the vehicle reacts at different states), or disruptive (saturating queues and bandwidth to crowd out legitimate traffic). Because replays preserve valid syntax and often valid context, they can blend with normal operations, especially during periods with reduced monitoring or when counters and windows reset (e.g., handovers, safing entries). On encrypted links, metadata replays (acquisition beacons, schedule requests) may still yield informative responses.
	.01	Command Packets	Threat actors may resend authentic-looking telecommands that were previously accepted by the spacecraft. Captures may include whole command PDUs with framing, CRC/MAC, counters, and timetags intact, or they may be reconstructed from operator tooling and procedure logs. When timing, counters, and mode preconditions align, the replayed packet can cause the same effect: toggling relays, initiating safing or recovery scripts, adjusting tables, commanding momentum dumps, or scheduling delta-v events. Even when outright execution fails, repeated “near-miss” injections can map acceptance windows, rate/size limits, and interlocks by observing the spacecraft’s acknowledgments and state changes. At scale, streams of valid-but-stale commands can congest command queues, delay legitimate activity, or trigger nuisance FDIR responses.
	.02	Bus Traffic Replay	Instead of the RF path, the attacker targets internal command/data handling by injecting or retransmitting messages on the spacecraft bus (e.g., 1553, SpaceWire, custom). Because many subsystems act on the latest message or on message rate rather than on uniqueness, a flood of historical yet well-formed frames can consume bandwidth, starve critical publishers, or cause subsystems to perform the same action repeatedly. Secondary effects include stale sensor values being re-consumed, watchdog timers being reset at incorrect intervals, and autonomy rules misclassifying the situation due to out-of-order but valid-looking events. On time-triggered or scheduled buses, replaying at precise offsets can collide with or supersede legitimate messages, steering system state without changing software. The goal is to harness the bus’s determinism, repeating prior internal stimuli to recreate prior effects or to induce resource exhaustion.
EX-0002		Position, Navigation, and Timing (PNT) Geofencing	Malware or implanted procedures execute only when the spacecraft’s state meets geometric and temporal criteria. Triggers can be defined in orbital elements, inertial or Earth-fixed coordinates, relative geometry, lighting conditions, or time references. The code monitors on-board navigation solutions, ephemerides, or propagated TLEs and arms itself when thresholds are met (e.g., “only fire over region X,” “only activate during LEOP,” or “only run within N seconds of a scheduled downlink.”) Geofencing reduces exposure and aids deniability: triggers are rare, aligned with mission cadence, and hard to reproduce on the ground. More elaborate variants require conjunctions of conditions (position + attitude + clock epoch) or incorporate drift so the trigger slowly evolves with the orbit. The result is effect-on-demand: execution occurs precisely where and when the actor intends, while remaining dormant elsewhere.
EX-0003		Modify Authentication Process	The adversary alters how the spacecraft validates authority so that future inputs are accepted on their terms. Modifications can target code (patching flight binaries, hot-patching functions in memory, hooking command handlers), data (changing key identifiers, policy tables, or counter initialization), or control flow (short-circuiting MAC checks, widening anti-replay windows, bypassing interlocks on specific opcodes). Common choke points include telecommand verification routines, bootloader or update verifiers, gateway processors that bridge payload and bus traffic, and maintenance dictionaries invoked in special modes. Subtle variants preserve outward behavior, producing normal-looking acknowledgments and counters, while internally accepting a broader set of origins, opcodes, or timetags. Others introduce conditional logic so the backdoor only activates under specific geometry or timing, masking during routine audit. Once resident, the modified process becomes the new trust oracle, enabling recurring execution for the attacker and, in some cases, denying legitimate control by causing authentic inputs to fail verification or to be deprioritized.
EX-0005		Exploit Hardware/Firmware Corruption	The adversary achieves execution or effect by corrupting or steering behavior beneath the software stack, in device firmware, programmable logic, or the hardware itself. Examples include tampering with firmware images or configuration blobs burned into non-volatile memory; targeting MCU/SoC boot ROM fallbacks; editing FPGA bitstreams or partial-reconfiguration frames; or leveraging physical phenomena and timing to flip bits or skip checks. Because these actions occur below or alongside the operating system and application FSW, traditional endpoint safeguards see normal interfaces while trust anchors are already altered.
	.01	Design Flaws	Threat actors may exploit inherent properties or errata in the hardware/logic design rather than injecting new code. Levers include undocumented or weakly specified behaviors (scan chains, test modes, debug straps), counter/timer rollovers and wraparound, interrupt storms and priority inversions, MMU/TLB corner cases, DMA engines that can write outside intended buffers, and bus arbitration or clock-domain crossing issues that permit stale or reordered writes. RNGs and crypto accelerators with flawed seeding or side-channel leakage can expose secrets or enable predictable authentication values. In programmable logic, vulnerable state machines, insufficient reset paths, and hazardous partial-reconfiguration regions create opportunities to drive the design into privileged or undefined states. Even reliability features can be turned: hardware timers intended for liveness can be paced to starve control loops; ECC policies can be nudged so correction conceals attacker-induced drift. The common thread is using the platform’s own guarantees, timing, priority, persistence, or fault handling, to cause privileged behavior that the software stack accepts as “by design.”
	.02	Malicious Use of Hardware Commands	Threat actors may issue low-level device or maintenance commands that act directly on hardware, bypassing much of the high-level command mediation. These may be memory-mapped register writes forwarded over the bus, vendor-specific instrument/control opcodes, built-in-test and calibration modes, boot-mode or fuse-programming sequences, file/sector operations to on-board non-volatile stores, or actuator primitives for wheels, thrusters, motors, heaters, and RF chains. Because these interfaces exist to configure sensors, zero momentum, switch power domains, tune gains, or adjust clocks, they can also be sequenced to produce harmful effects: over-driving mechanisms, altering persistent calibration, disabling watchdogs, or switching timing sources. Some hardware command sets are only exposed in maintenance or contingency modes, while others are always reachable through gateway processors that translate high-level telecommands into device-level operations. By crafting orders that respect expected framing and rate/size limits, the adversary can induce mechanical, electrical, or logical state changes with immediate, high-privilege impact, all while appearing to exercise legitimate device capabilities.
EX-0006		Disable/Bypass Encryption	The adversary alters how confidentiality or integrity is applied so traffic or data is processed in clear or with weakened protection. Paths include toggling configuration flags that place links or storage into maintenance/test modes; forcing algorithm “fallbacks” or null ciphers; downgrading negotiated suites or keys; manipulating anti-replay/counter state so checks are skipped; substituting crypto libraries or tables during boot/update; and selecting alternate routes that carry the same content without encryption. On some designs, distinct modes handle authentication and confidentiality separately, allowing an actor who obtains authentication material to request unencrypted service or to switch to legacy profiles. The end state is that command, telemetry, or data products traverse a path the spacecraft accepts while cryptographic protection is absent, weakened, or inconsistently applied, enabling subsequent tactics such as inspection, manipulation, or exfiltration.
EX-0007		Trigger Single Event Upset	The attacker induces or opportunistically exploits a single-event upset (SEU), a transient bit flip or latch disturbance in logic or memory, so that software executes in a state advantageous to the attack. SEUs arise when charge is deposited at sensitive nodes by energetic particles or intense electromagnetic stimuli. An actor may time operations to coincide with natural radiation peaks or use artificial means from close range. Outcomes include corrupted stacks or tables, altered branch conditions, flipped configuration bits in FPGAs or controllers, and transient faults that push autonomy/FDIR into recovery modes with broader command acceptance. SEU exploitation is probabilistic; the technique couples repeated stimulation with careful observation of mode transitions, watchdogs, and error counters to land the system in a desired but nominal-looking state from which other actions can proceed.
EX-0008		Time Synchronized Execution	Malicious logic is arranged to run at precise times derived from onboard clocks or distributed time sources. The trigger may be absolute or relative. Spacecraft commonly maintain multiple clocks and counters and schedule autonomous sequences against them. An attacker leverages this machinery to ensure effects occur during tactically advantageous windows. Time-based execution reduces exposure, simplifies coordination across assets, and makes reproduction difficult in lab settings that lack the same temporal context.
	.01	Absolute Time Sequences	Execution is keyed to a fixed wall-clock timestamp or epoch, independent of current vehicle state. The implant watches a trusted time source, GNSS-derived time, crosslink-distributed network time, oscillator-disciplined UTC/TAI, or mission elapsed time anchored at activation, and triggers exactly at a programmed date/time. Absolute triggering supports coordinated multi-asset actions and allows long dormancy with a precise activation moment. Variants incorporate calendar logic (e.g., “first visible pass after YYYY-MM-DD hh:mm:ss”) or guard bands to fire only if the clock is within certain tolerances, ensuring the event occurs even with minor drift yet remains rare enough to blend with scheduled operations.
	.02	Relative Time Sequences	Execution is keyed to elapsed time since a reference event. The implant latches a start point, boot, reset, safing entry/exit, receipt of a particular telemetry/command pattern, achievement of sun-pointing, and arms a countdown or set of offsets (“N seconds after event,” “repeat every M cycles”). Relative sequences are resilient to clock discontinuities and mirror how many spacecraft schedule internal activities (e.g., after boot, run calibrations; after acquisition, start downlink). An attacker exploits this to ensure the trigger fires only within specific operational phases and to survive resets that would thwart absolute timestamps: after every reboot, wait for housekeeping steady state, then act; or, after a wheel unload completes, inject an additional command while control laws are in a known configuration.
EX-0009		Exploit Code Flaws	The adversary executes actions on-board by abusing defects in software that runs on the vehicle, ranging from application logic in flight software to libraries, drivers, and supporting services. Outcomes range from arbitrary code execution and privilege escalation to silent logic manipulation (e.g., bypassing interlocks, suppressing alarms) that appears operationally plausible. The hallmark of this technique is that the attacker co-opts existing code paths, often rarely used ones, to run unintended behavior under nominal interfaces. These attacks may be extremely targeted and tailored to specific coding errors introduced as a result of poor coding practices or they may target known issues in the commercial software components.
	.01	Flight Software	Flight software presents rich attack surface where mission-specific parsing and autonomy live. Vulnerable components include command and telemetry handlers, table loaders, file transfer services, mode management and safing logic, payload control applications, and gateway processes that bridge payload and bus protocols. Typical flaws are unchecked lengths and indices in command fields, arithmetic overflows in rate/size calculations, insufficient validation of table contents, format-string misuse in logging, incomplete state cleanup across rapid mode changes, and race conditions in concurrent message processing. Some FSW suites expose operator-facing APIs or scripting/procedure engines used for automation; malformed invocations can coerce unexpected behaviors or enable arbitrary expressions. Because many subsystems act on “last write wins,” logic errors can yield durable configuration changes without obvious anomalies in protocol syntax. Successful exploitation lets an adversary execute code, alter persistent parameters, or chain effects across partitions that would otherwise be segmented by design.
	.02	Operating System	At the OS layer the attacker targets primitives that schedule work and mediate hardware. Maintenance builds may expose shells or management consoles; misconfigurations around these interfaces can provide paths to command interpreters or privileged syscalls. Exploitation yields kernel-mode execution, arbitrary memory read/write, or control of scheduling and address spaces, letting the actor tamper with FSW processes, intercept command paths, or manipulate storage and bus drivers beneath application checks. The technique leverages generic OS weaknesses adapted to the spacecraft’s particular build, turning low-level control into mission-facing effects that appear to originate from legitimate processes.
	.03	Known Vulnerability (COTS/FOSS)	Using knowledge of the software composition on-board, the adversary maps components and versions to publicly or privately known defects and then crafts inputs to trigger them. Typical targets include standard libraries (libc, STL), cryptographic and compression libraries, protocol stacks (CCSDS implementations, IP over space links, SpaceWire bridges), filesystems and parsers (FITS/CCSDS packetization, custom table formats), and vendor SDKs for radios, sensors, or payloads. Triggers arrive as well-formed but malicious packets, frames, or files whose edge-case fields exercise version-specific bugs, overflowing a parser, bypassing an authentication check, or causing a kernel/driver fault that reboots into a more permissive mode. Because these flaws are documented somewhere, exploitation emphasizes matching the exact build and build-time options used on the mission.
EX-0010		Malicious Code	The adversary achieves on-board effects by introducing executable logic that runs on the vehicle, either native binaries and scripts, injected shellcode, or “data payloads” that an interpreter treats as code (e.g., procedure languages, table-driven automations). Delivery commonly piggybacks on legitimate pathways: software/firmware updates, file transfer services, table loaders, maintenance consoles, or command sequences that write to executable regions. Once staged, activation can be explicit (a specific command, mode change, or file open), environmental (time/geometry triggers), or accidental, where operator actions or routine autonomy invoke the implanted logic. Malicious code can target any layer it can reach: altering flight software behavior, manipulating payload controllers, patching boot or device firmware, or installing hooks in drivers and gateways that bridge bus and payload traffic. Effects range from subtle logic changes (quiet data tampering, command filtering) to overt actions (forced mode transitions, resource starvation), and may include secondary capabilities like covert communications, key material harvesting, or persistence across resets by rewriting images or configuration entries.
	.01	Ransomware	Ransomware on a spacecraft encrypts data or critical configuration so that nominal operations can no longer proceed without the attacker’s cooperation. Targets include mass-memory file stores (engineering telemetry, payload data), configuration and command tables, event logs, on-board ephemerides, and even intermediate buffers used by downlink pipelines. Some variants interfere with key services instead of bulk data, e.g., encrypting a command dictionary or table index so valid inputs are rejected, or wrapping the payload data path in an attacker-chosen cipher so downlinked products appear as noise. By denying access to on-board content or control artifacts at scale, attackers convert execution into bargaining power or irreversible mission degradation.
	.02	Wiper Malware	Wipers deliberately destroy or irreversibly corrupt data and, in some cases, executable images to impair or end mission operations. Destructive routines may overwrite with patterns or pseudorandom data, repeatedly reformat volumes, trigger wear mechanisms on non-volatile memory, or manipulate low-level translation layers so recovery tools see a blank or inconsistent device. Activation can be immediate or staged, sleeping until a specific time, pass, or maintenance action, and may be paired with anti-recovery steps such as erasing checksums, undo logs, or golden images. Because wipers operate at storage and image layers that underpin many subsystems, collateral effects can cascade: autonomy enters safing without viable recovery paths, downlinks carry only noise, and subsequent updates cannot be authenticated or applied. The defining feature is irreversible loss of data or executables as the primary objective, rather than concealment or monetization.
	.03	Rootkit	A rootkit hides the presence and activity of other malicious components by interposing on the mechanisms that report system state. On spacecraft this can occur within flight software processes, at OS kernel level, inside separation kernels/hypervisors, or down in system firmware where drivers and initialization routines run. Techniques include API and syscall hooking, patching message queues and inter-process communication paths, altering task lists and scheduler views, filtering telemetry packets and event logs, and rewriting sensor or health values before they are recorded or downlinked. Rootkits may also hook command handlers and gateways so certain opcodes, timetags, or sources are silently accepted or ignored while external observers see normal acknowledgments. Because many missions rely on deterministic procedures and limited observability, even small alterations to reporting can make malicious actions appear as plausible mode transitions or benign anomalies. Persistence often pairs with the concealment layer, with the rootkit reinjecting companions after resets or rebuilds by monitoring for specific files, tables, or image loads and modifying them on the fly.
	.04	Bootkit	A bootkit positions itself in the pre-OS boot chain so that it executes before normal integrity checks and can shape what the system subsequently trusts. After seizing early control, the bootkit can redirect image selection, patch kernels or flight binaries in memory, adjust device trees and driver tables, or install hooks that persist across warm resets. Some variants maintain shadow copies of legitimate images and present them to basic verification routines while steering actual execution to a modified payload; others manipulate fallback logic so recovery modes load attacker-controlled code. Because the boot path initializes memory maps, buses, and authentication material, a bootkit can also influence key/counter setup and gateway configurations, creating conditions favorable to later tactics. The central characteristic is precedence: by running first, the implant defines the reality higher layers observe, ensuring that every subsequent component launches under conditions curated by the attacker.
EX-0011		Exploit Reduced Protections During Safe-Mode	The adversary times on-board actions to the period when the vehicle is in safe-mode and operating with altered guardrails. In many designs, safe-mode enables contingency command dictionaries, activates alternate receivers or antennas, reduces data rates, and prioritizes survival behaviors (sun-pointing, thermal/power conservation). Authentication checks, anti-replay windows, rate/size limits, and interlocks may differ from nominal; counters can be reset, timetag screening relaxed, or maintenance procedures made available for recovery. Ground cadence also changes, longer passes, emergency scheduling, atypical station selection, creating predictable windows for interaction. Using knowledge of these patterns, an attacker issues maintenance-looking loads, recovery scripts, parameter edits, or boot/patch sequences that the spacecraft is primed to accept while safed. Because responses (telemetry beacons, acknowledgments, mode bits) resemble normal anomaly recovery, the first execution event blends with expected behavior, allowing unauthorized reconfiguration, software modification, or state manipulation to occur under the cover of fault response.
EX-0012		Modify On-Board Values	The attacker alters live or persistent data that the spacecraft uses to make decisions and route work. Targets include device and control registers, parameter and limit tables, internal routing/subscriber maps, schedules and timelines, priority/QoS settings, watchdog and timer values, autonomy/FDIR rule tables, ephemeris and attitude references, and power/thermal setpoints. Many missions expose legitimate mechanisms for updating these artifacts, direct memory read/write commands, table load services, file transfers, or maintenance procedures, which can be invoked to steer behavior without changing code. Edits may be transient (until reset) or latched/persistent across boots; they can be narrowly scoped (a single bit flip on an enable mask) or systemic (rewriting a routing table so commands are misdelivered). The effect space spans subtle biasing of control loops, selective blackholing of commands or telemetry, rescheduling of operations, and wholesale changes to mode logic, all accomplished by modifying the values the software already trusts and consumes.
	.01	Registers	Threat actors may target the internal registers of the victim spacecraft in order to modify specific values as the FSW is functioning or prevent certain subsystems from working. Most aspects of the spacecraft rely on internal registers to store important data and temporary values. By modifying these registers at certain points in time, threat actors can disrupt the workflow of the subsystems or onboard payload, causing them to malfunction or behave in an undesired manner.
	.02	Internal Routing Tables	Threat actors may rewrite the maps that tell software where to send and receive things. In publish/subscribe or message-queued flight frameworks, tables map message IDs to subscribers, opcodes to handlers, and pipes to processes; at interfaces, address/port maps define how traffic traverses bridges and gateways (e.g., SpaceWire node/port routes, 1553 RT/subaddress mappings, CAN IDs). By altering these structures, commands can be misdelivered, dropped, duplicated, or routed through unintended paths; telemetry can be redirected or blackholed; and handler bindings can be swapped so an opcode triggers the wrong function. Schedule/routing hybrids, used to sequence activities and distribute results, can be edited to reorder execution or to create feedback loops that occupy bandwidth and processor time. The result is control over who hears what and when, achieved by changing the lookup tables that underpin command/telemetry distribution rather than the code that processes them.
	.03	Memory Write/Loads	The adversary uses legitimate direct-memory commands or load services to place chosen bytes at chosen addresses. Many spacecraft support raw read/write operations, block loads into RAM or non-volatile stores, and table/file loaders that copy content into working memory. With knowledge of address maps and data structures, an attacker can patch function pointers or vtables, alter limit and configuration records, seed scripts or procedures into interpreter buffers, adjust DMA descriptors, or overwrite portions of executable images resident in RAM. Loads may be sized and paced to fit link and queue constraints, then activated by a subsequent command, mode change, or natural reference by the software.
	.04	App/Subscriber Tables	In publish/subscribe flight frameworks, applications and subsystems register interest in specific message classes via subscriber (or application) tables. These tables map message IDs/topics to subscribers, define delivery pipes/queues, and often include filters, priorities, and rate limits. By altering these mappings, an adversary can quietly reshape information flow: critical consumers stop receiving health or sensor messages; non-critical tasks get flooded; handlers are rebound so an opcode or message ID reaches the wrong task; or duplicates create feedback loops that consume bandwidth and CPU. Because subscription state is usually read at init or refreshed on command, subtle edits can persist across reboots or take effect at predictable times. Similar effects appear in legacy MIL-STD-1553 deployments by modifying Remote Terminal (RT), subaddress, or mode-code configurations so that messages are misaddressed or dropped at the bus interface. The net result is control-by-misdirection: the software still “works,” but the right data no longer reaches the right recipient at the right time.
	.05	Scheduling Algorithm	Spacecraft typically rely on real-time scheduling, fixed-priority or deadline/periodic schemes, driven by timers, tick sources, and per-task parameters. Threat actors target these parameters and associated tables to skew execution order and timing. Edits may change priorities, periods, or deadlines; adjust CPU budgets and watchdog thresholds; alter ready-queue disciplines; or reconfigure timer tick rates and clock sources. They may also modify task affinities, message-queue depths, and interrupt masks so preemption and latency characteristics shift. Small changes can have large effects: high-rate control loops see added jitter, estimator updates miss deadlines, command/telemetry handling starves, or low-priority maintenance tasks monopolize cores due to mis-set periods. Manipulated schedules can create intermittent, state-dependent malfunctions that are hard to distinguish from environmental load. The essence of the technique is to weaponize time, reshaping when work happens so that otherwise correct code produces unsafe or exploitable behavior.
	.06	Science/Payload Data	Payload data, and the metadata that gives it meaning, can be altered in place to steal value, mislead users, or degrade mission outputs. Targets include raw detector frames, packetized Level-0 streams, onboard preprocessed products, and file catalogs/directories on mass memory. Adjacent metadata such as timestamps, pointing/attitude tags, calibration coefficients, compression settings, and quality flags are equally potent; slight bias in a calibration table or time tag can skew entire downlink campaigns while appearing routine. An adversary may rewrite frame headers, reorder packets, substitute segments from prior passes, or flip quality bits so ground pipelines silently discard or misclassify products. Recorder index manipulation can orphan files or cause downlinks to serve stale or fabricated content. Because many missions perform some processing or filtering onboard, tampering upstream of downlink propagates forward as “authoritative” truth, jeopardizing mission objectives without obvious protocol anomalies.
	.07	Propulsion Subsystem	Propulsion relies on parameters and sensed values that govern burns, pressure management, and safing. Editable items include thruster calibration and minimum impulse bit, valve timing and duty limits, inhibit masks, delta-V tables, plume keep-out constraints, tank pressure/temperature thresholds, leak-detection limits, and momentum-management coupling with attitude control. By modifying these, an adversary can provoke over-correction, waste propellant through repeated trims, bias orbit maintenance, or trigger protective sequences at inopportune times. False pressure or temperature readings can cause autonomous venting or lockouts; tweaked alignment matrices or misapplied gimbal limits can yield off-axis thrust and attitude excursions; altered desaturation rules can induce frequent wheel unloads that sap resources. Because consumables are finite and margins tight, even modest parameter drift can shorten mission life or violate keep-out and conjunction constraints while presenting as “normal” control activity.
	.08	Attitude Determination & Control Subsystem	ADCS depends on tightly coupled models and parameters: star-tracker catalogs and masks, sensor alignments and bias terms, gyro scale factors and drift rates, estimator covariances and process/measurement noise, controller gains and saturation limits, wheel/CMG torque constants, magnetic torquer maps, and sun sensor thresholds. Editing these values skews estimation or control, producing slow bias, limit cycles, loss of lock, or abrupt safing triggers. For example, a small change to a star-tracker mask can force frequent dropouts; an inflated gyro bias drives the filter away from truth; softened actuator limits or mis-set gains let disturbances accumulate; altered sun-point entry criteria cause unnecessary mode switches. Secondary impacts propagate to power, thermal, and communications because pointing and geometry underpin array generation, radiator view factors, and antenna gain. The technique turns the spacecraft against itself by nudging the parameters that close the loop between what the vehicle believes and how it responds.
	.09	Electrical Power Subsystem	Adversaries alter parameters and sensed values that govern power generation, storage, and distribution so the spacecraft draws or allocates energy in harmful ways. Editable items include bus voltage/current limits, MPPT setpoints and sweep behavior, array and SADA modes, battery charge/discharge thresholds and temperature derates, state-of-charge estimation constants, latching current limiter (LCL) trip/retry settings, load-shed priorities, heater duty limits, and survival/keep-alive rules. By changing these, a threat actor can drive excess consumption (e.g., disabling load shed, raising heater floors), misreport remaining energy (skewed SoC), or push batteries outside healthy ranges, producing brownouts, repeated safing, or premature capacity loss. Manipulating thresholds and hysteresis can also create oscillations where loads repeatedly drop and re-engage, wasting energy and stressing components. The effect is accelerated depletion or misallocation of finite power, degrading mission operations and potentially preventing recovery after eclipse or anomalies.
	.10	Command & Data Handling Subsystem	C&DH relies on tables and runtime values that define how commands are parsed, queued, and dispatched and how telemetry is collected, stored, and forwarded. Targets include opcode-to-handler maps, argument limits and schemas, queue depths and priorities, message ID routing, publish/subscribe bindings, timeline/schedule entries, file catalog indices, compression and packetization settings, and event/telemetry filters. Edits to these artifacts reshape control and visibility: commands are delayed, dropped, or misrouted; telemetry is suppressed or redirected; timelines slip; and housekeeping/data products are repackaged in ways that confuse ground processing. Because many frameworks treat these values as authoritative configuration, small changes can silently propagate across subsystems, degrading responsiveness, creating backlogs, or severing the logical pathways that keep the vehicle coordinated, without modifying the underlying code.
	.11	Watchdog Timer (WDT)	Watchdogs supervise liveness by requiring software to “pet” within defined windows or the system resets. Threat actors manipulate WDT behavior by changing timeout durations, windowed-WDT bounds, reset actions, enable/mask bits, or the source that performs the petting (e.g., moving it into a low-level ISR so higher layers can be stalled indefinitely). Software WDTs can be disabled or starved; hardware WDTs are influenced via control registers, strap pins, or supervisor commands that alter prescalers and reset ladders. Outcomes include preventing intended resets so runaway tasks consume power and bandwidth, or forcing repeated resets at tactically chosen moments, e.g., during updates or handovers, to keep the system in a degraded or easily predictable state. The technique converts a safety mechanism into a tool for either unbounded execution or rhythmic disruption, depending on how the WDT parameters are rewritten.
	.12	System Clock	Spacecraft maintain multiple time bases and distribute time to schedule sequences, validate timetags, manage anti-replay counters, and align navigation/attitude processing. By writing to clock registers, altering time-distribution services, switching disciplining sources, or biasing oscillator parameters, an adversary can skew these references. Effects include reordering or prematurely firing stored command sequences, invalidating timetag checks, desynchronizing counters used by authentication or ranging, misaligning estimator windows, and corrupting timestamped payload data. Even small offsets can accumulate into observable misbehavior when autonomy and scheduling depend on tight temporal guarantees. The result is execution that happens at the wrong moment, or not at all, because the system’s notion of “now” has been shifted.
	.13	Poison AI/ML Training Data	When missions employ AI/ML, for onboard detection/classification, compression, anomaly screening, guidance aids, or ground-side planning, training data becomes a control surface. Data poisoning inserts crafted examples or labels into the training corpus or fine-tuning set so the resulting model behaves incorrectly while appearing valid. Variants include clean-label backdoors (benign-looking samples with a hidden trigger that later induces a targeted response), label flipping and biased sampling (to skew decision boundaries), and corruption of calibration/ground-truth products that the pipeline trusts. For space systems, poisoning may occur in science archives, test vectors, simulated scenes, or housekeeping datasets used to train autonomy/anomaly models; models trained on poisoned corpora are then packaged and uplinked as routine updates. Once fielded, a simple trigger pattern in imagery, telemetry, or RF features can cause misclassification, suppression, or false positives at the time and place the adversary chooses, turning model behavior into an execution mechanism keyed by data rather than code.
EX-0013		Flooding	Flooding overwhelms a communication or processing path by injecting traffic at rates or patterns the system cannot comfortably absorb. In space contexts this can occur across layers: RF/optical links (continuous carriers, wideband noise, or protocol-shaped bursts); link/protocol layers (valid-looking frames at excessive cadence); application layers (command and telemetry messages that saturate parsers and queues); and internal vehicles buses where repeated messages starve critical publishers. Effects range from outright denial of service, dropped commands, lost telemetry, missed windows, to subtler corruption, such as out-of-order processing, watchdog trips, or autonomy entering protective modes due to backlogged health data. Secondary impacts include power and thermal strain as decoders, modems, or software loops spin at maximum duty, storage filling from retries, and control loops jittering when their messages are delayed. Timing matters: floods during handovers, maneuvers, or safing transitions can magnify consequences because margins are thinnest.
	.01	Valid Commands	Here the adversary saturates paths with legitimate telecommands or bus messages so the spacecraft burns scarce resources honoring them. Inputs may be innocuous (no-ops, time queries, telemetry requests) or low-risk configuration edits, but at scale they consume command handler cycles, fill queues, generate events and logs, trigger acknowledgments, and provoke downstream work in subsystems (e.g., repeated state reports, mode toggles, or file listings). On internal buses, valid actuator or housekeeping messages replayed at high rate can starve higher-priority publishers or cause control laws to chase stale stimuli. Because the traffic is syntactically correct, and often contextually plausible, the system attempts to process it rather than discard it early, increasing CPU usage, memory pressure, and power draw. Consequences include delayed or preempted legitimate operations, transient loss of commandability, and knock-on FDIR activity as deadlines slip and telemetry appears inconsistent.
	.02	Erroneous Input	In this variant, the attacker injects non-useful energy or data, noise, malformed frames, or near-valid messages, so receivers and parsers labor to acquire, decode, and reject it. At the RF layer, wideband or protocol-shaped interference drives AGC and clock recovery to hunt, elevates BER, and forces repeated acquisitions; at the link layer, frames with correct preambles but bad CRCs keep decoders busy while yielding no payload; at the application layer, malformed packets force parse/validate/deny cycles that still consume CPU and fill error logs. On internal buses, collisions or bursts of misaddressed traffic reduce effective bandwidth and reorder legitimate messages. Even though little of the injected content passes semantic checks, the effort of dealing with it crowds out real work and may trigger retransmission storms or fallback modes that further increase load. The hallmark is volumetric invalid activity, crafted to engage front ends and parsers just long enough, that degrades integrity and availability without relying on privileged or authenticated commands.
EX-0014		Spoofing	The adversary forges inputs that subsystems treat as trustworthy truth, time tags, sensor measurements, bus messages, or navigation signals, so onboard logic acts on fabricated reality. Because many control loops and autonomy rules assume data authenticity once it passes basic sanity checks, carefully shaped spoofs can trigger mode transitions, safing, actuator commands, or payload behaviors without touching flight code. Spoofing may occur over RF (e.g., GNSS, crosslinks, TT&C beacons), over internal networks/buses (message injection with valid identifiers), or at sensor/actuator interfaces (electrical/optical stimulation that produces plausible readings). Effects range from subtle bias (drifting estimates, skewed calibrations) to acute events (unexpected slews, power reconfiguration, recorder re-indexing), and can also pollute downlinked telemetry or science products so ground controllers interpret a false narrative. The hallmark is that the spacecraft chooses the adversary’s action path because the forged data passes through normal processing chains.
	.01	Time Spoof	Time underpins sequencing, anti-replay, navigation filtering, and data labeling. An attacker that forges or biases the time seen by onboard consumers can reorder stored command execution, break timetag validation, desynchronize counters, and misalign estimation windows. Spoofing vectors include manipulating the distributed time service, introducing a higher-priority/cleaner time source (e.g., GNSS-derived time), or crafting messages that cause clock discipline to slew toward attacker-chosen values. Once time shifts, autonomous routines keyed to epochs, wheel unloads, downlink starts, heater schedules, fire early/late or not at all, and telemetry appears inconsistent to ground analysis. The signature is correct-looking time metadata that steadily or abruptly departs from truth, driving downstream logic to act at the wrong moment.
	.02	Bus Traffic Spoofing	Here the adversary forges messages on internal command/data paths (e.g., 1553, SpaceWire, CAN, custom). By emitting frames with valid identifiers, addresses, and timing, the attacker can make subscribers accept actuator setpoints, power switch toggles, mode changes, or housekeeping values that originated off-path. Because many consumers act on “latest value wins” or on message cadence, forged traffic can mask real publishers, starve critical topics, or force handlers to execute unintended branches. Gateways that translate between networks amplify impact: a spoofed message on one side can propagate to multiple domains as legitimate payload. Outcomes include misdelivered commands, silent configuration drift, and control loops chasing phantom stimuli, all while bus monitors show protocol-conformant traffic.
	.03	Sensor Data	The attacker presents fabricated or biased measurements that estimation and control treat as ground truth. Targets include attitude/position sensors (star trackers, gyros/IMUs, sun sensors, magnetometers, GNSS), environmental and health sensors (temperatures, currents, voltages, pressures), and payload measurements used in autonomy. Spoofs may be injected electrically at interfaces, optically (blinding/dazzling trackers or sun sensors), magnetically, or by crafting packets fed into sensor gateways. Even small, consistent biases can drive filters to incorrect states; stepwise changes can trigger fault responses or mode switches. Downstream, timestamps, quality flags, and derived products inherit the deception, creating uncertainty for operators and potentially inducing temporary loss of service as autonomy reacts to a world that never existed.
	.04	Position, Navigation, and Timing (PNT) Spoofing	The adversary transmits GNSS-like signals (or manipulates crosslink-distributed time/ephemeris) so the spacecraft’s navigation solution reflects attacker-chosen states. With believable code phases, Doppler, and navigation messages, the victim can be pulled to a false position/velocity/time, causing downstream functions, attitude pointing limits, station visibility prediction, eclipse timing, antenna pointing, and anti-replay windows, to misbehave. Even when GNSS is not the primary navigation source, spoofed PNT can bias timekeeping or seed filters that fuse multiple sensors, leading to mis-scheduling and errant control. The defining feature is externally provided navigation/time that passes validity checks yet encodes a crafted trajectory or epoch.
EX-0015		Side-Channel Attack	Adversaries extract secrets or steer execution by observing or perturbing physical byproducts of computation rather than the intended interfaces. Passive channels include timing, power draw, electromagnetic emissions, acoustic/optical leakage, and thermal patterns correlated with operations such as key use, counter updates, or parser activity. Active channels deliberately induce faults during runtime, e.g., voltage or clock glitches, electromagnetic/laser injection, or targeted radiation, to flip bits, skip checks, or bias intermediate values. On spacecraft, prime targets include crypto modules, SDR/FPGA pipelines, bootloaders, and bus controllers whose switching behavior or error handling reveals protocol state or key material. With sufficient samples, or with repeated fault attempts, statistical features emerge that reduce entropy of the sensitive variable under study; in effect, a successful fault campaign turns into information leakage comparable to a passive side channel. Collection vantage points range from on-orbit proximity (for EM/optical), to ATLO and ground test (for direct probing), to instrumented compromised hardware already in the signal path.
PER-0001		Memory Compromise	The adversary arranges for malicious content to survive resets and mode changes by targeting memories and execution paths that initialize the system. Candidates include boot ROM handoff vectors, first/second-stage loaders, non-volatile images (flash/EEPROM), “golden” fallback partitions, configuration words/fuses, and RAM regions reconstructed at start-up from stored files or tables. Persistence may also ride auto-run mechanisms, init scripts, procedure engines, stored command sequences, or event hooks that execute on boot, safe-mode entry/exit, time triggers, or receipt of specific telemetry/commands. Variants keep the core payload only in RAM but ensure it is reloaded after every restart by patching copy-on-boot routines, altering file catalogs, or modifying table loaders so the same bytes are restored. The common thread is control of where the spacecraft looks for what to run next, so unauthorized logic is reinstated whenever the system resets or transitions modes.
PER-0002		Backdoor	A backdoor is a covert access path that bypasses normal authentication, authorization, or operational checks so the attacker can reenter the system on demand. Backdoors may be preexisting (undocumented service modes, maintenance accounts, debug features) or introduced by the adversary during development, integration, or on-orbit updates. Triggers range from “magic” opcodes and timetags to specific geometry/time conditions, counters, or data patterns embedded in routine traffic. The access they provide varies from expanded command sets and relaxed rate/size limits to alternate communications profiles and hidden file/parameter interfaces. Well-crafted backdoors blend with nominal behavior, appearing as ordinary operations while quietly accepting instructions that other paths would reject, thereby sustaining the attacker’s foothold across passes, resets, and operator handovers.
	.01	Hardware Backdoor	Hardware backdoors leverage properties of the physical design to provide durable, low-visibility reentry. Examples include enabled test/scan chains, manufacturing or boot-strap modes invoked by pins or registers, persistent debug interfaces (JTAG/SWD/UART), undocumented device commands, and logic inserted in FPGA/ASIC designs that activates under specific stimuli. Because these mechanisms sit below or beside flight software, they can grant direct access to buses, memories, or peripheral control even when higher layers appear healthy. Triggers may be electrical (pin states, voltage/clock sequences), protocol-level (special patterns on an instrument link), or environmental/temporal (particular temperature ranges, timing offsets). Once on orbit, such pathways are difficult to remove or reconfigure, allowing the attacker to persist by reusing the same physical entry points whenever conditions are met.
	.02	Software Backdoor	Software backdoors are code paths intentionally crafted or later inserted to provide privileged functionality on cue. In flight contexts, they appear as hidden command handlers, alternate authentication checks, special user/role constructs, or procedure/script hooks that accept nonpublic inputs. They can be embedded in flight applications, separation kernels or drivers, gateway processors that translate bus/payload traffic, or update/loader utilities that handle tables and images. SDR configurations offer another avenue: non-public waveforms, subcarriers, or framing profiles that, when selected, expose a private command channel. Activation is often conditional, specific timetags, geometry, message sequences, or file names, to keep the feature dormant during routine testing and operations. Once present, the backdoor provides a repeatable way to execute commands or modify state without traversing the standard control surfaces, sustaining the adversary’s access over time.
PER-0003		Ground System Presence	The adversary maintains long-lived access by residing within mission ground infrastructure that already has end-to-end reach to the spacecraft. Persistence can exist in operator workstations and mission control software, schedulers/orchestrators, station control (antenna/mount, modem/baseband), automation scripts and procedure libraries, identity and ticketing systems, and cloud-hosted mission services. With this foothold, the actor can repeatedly queue commands, updates, or file transfers during routine passes; mirror legitimate operator behavior to blend in; and refresh their tooling as software is upgraded. Presence on the ground also supports durable reconnaissance (pass plans, dictionaries, key/counter states) and continuous staging so each window to the vehicle can be exploited without re-establishing access.
PER-0004		Replace Cryptographic Keys	The adversary cements control by changing the cryptographic material the spacecraft uses to authenticate or protect links and updates. Targets include uplink authentication keys and counters, link-encryption/session keys and key-encryption keys (KEKs), key identifiers/selectors, and algorithm profiles. Using authorized rekey commands or key-loading procedures, often designed for over-the-air use, the attacker installs new values in non-volatile storage and updates selectors so subsequent traffic must use the attacker’s keys to be accepted. Variants desynchronize anti-replay by advancing counters or switching epochs, or strand operators by flipping profiles to a mode for which only the adversary holds parameters. Once replaced, the new material persists across resets and mode changes, turning the spacecraft into a node that recognizes the adversary’s channel while rejecting former controllers.
DE-0001		Disable Fault Management	The adversary suppresses or alters fault detection, isolation, and recovery (FDIR) so unauthorized actions proceed without triggering safing or alerts. Targets include watchdogs and heartbeat monitors; limit and sanity checks on sensor/command values; command interlocks and inhibit masks; voting and redundancy-management logic; and event/alert generation and routing. Techniques range from patching or bypassing checks in flight code, to rewriting parameter/limit tables, to muting publishers that report faults. More subtle variants desensitize thresholds, freeze counters, or delay responses just long enough for a malicious sequence to complete. With FDIR dulled or offline, anomalous states resemble nominal behavior and automated mitigations do not engage, masking the attack from ground oversight.
DE-0002		Disrupt or Deceive Downlink	Threat actors may target ground-side telemetry reception, processing, or display to disrupt the operator’s visibility into spacecraft health and activity. This may involve denial-based attacks that prevent the spacecraft from transmitting telemetry to the ground (e.g., disabling telemetry links or crashing telemetry software), or more subtle deception-based attacks that manipulate telemetry content to conceal unauthorized actions. Since telemetry is the primary method ground controllers rely on to monitor spacecraft status, any disruption or manipulation can delay or prevent detection of malicious activity, suppress automated or manual mitigations, or degrade trust in telemetry-based decision support systems.
	.03	Inhibit Spacecraft Functionality	In this variant, telemetry is suppressed at the source by manipulating on-board generation or transmission. Methods include disabling or pausing telemetry publishers, altering packet filters and rates, muting event/report channels, reconfiguring recorder playback, retuning/muting transmitters, or switching to modes that emit only minimal beacons. The spacecraft continues operating, but the downlink no longer reflects true activity or arrives too sparsely to support monitoring. By constraining what is produced or transmitted, the adversary reduces opportunities for detection while other actions proceed.
DE-0003		On-Board Values Obfuscation	The adversary manipulates housekeeping and control values that operators and autonomy rely on to judge activity, health, and command hygiene. Targets include command/telemetry counters, event/severity flags, downlink/reporting modes, cryptographic-mode indicators, and the system clock. By rewriting, freezing, or biasing these fields, and by selecting reduced or summary telemetry modes, unauthorized actions can proceed while the downlinked picture appears routine or incomplete. The result is delayed recognition, misattribution to environmental effects, or logs that cannot be reconciled post-facto.
	.01	Vehicle Command Counter (VCC)	The VCC tracks how many commands the spacecraft has accepted. An adversary masks activity by zeroing, freezing, or selectively decrementing the VCC, or by steering actions through paths that do not increment it (maintenance dictionaries, alternate receivers, hidden handlers). They may also overwrite the telemetry field that reports the VCC so ground displays show a lower or steady count while high volumes of commands are processed. This breaks simple “command volume” heuristics and makes bursty activity look normal.
	.02	Rejected Command Counter	This counter records commands that failed checks or were refused. To hide probing and trial-and-error, the adversary suppresses increments, periodically clears the value, or forges the downlinked field so rejection rates appear benign. Variants also tamper with associated reason codes or event entries, replacing them with innocuous outcomes. Analysts reviewing telemetry see no evidence of failed attempts even as the system is being exercised aggressively.
	.03	Command Receiver On/Off Mode	By toggling receiver enable states (per-receiver, per-antenna, or per-band), the adversary creates deliberate “quiet windows” in which outside intervention cannot arrive. Turning a command receiver off, or shifting to a configuration that ignores the primary path, allows queued actions or onboard procedures to run without interruption, while operators perceive a transient loss of commandability consistent with geometry or environment. Brief, well-timed toggles can also desynchronize counters and handovers, complicating reconstruction of what occurred.
	.04	Command Receivers Received Signal Strength	Threat actors may target the on-board command receivers received signal parameters (i.e., automatic gain control (AGC)) in order to stop specific commands or signals from being processed by the spacecraft. For ground controllers to communicate with spacecraft in orbit, the on-board receivers need to be configured to receive signals with a specific signal to noise ratio (ratio of signal power to the noise power). Targeting values related to the antenna signaling that are modifiable can prevent the spacecraft from receiving ground commands.
	.05	Command Receiver Lock Modes	Receivers advertise acquisition states, bit lock, frame lock, and command lock, that indicate readiness to accept telecommands. Adversaries leverage these indicators in two ways: (1) use command-lock tests to validate geometry, power, Doppler, and polarization without risking visible command execution; and (2) tamper with the values that report lock status so ground views never show that lock was achieved. Techniques include freezing or clearing lock flags and counters, raising/lowering internal thresholds so lock occurs without being reported (or vice versa), and timing brief lock intervals between telemetry samples. The result is a window where the spacecraft is receptive to commands while downlinked status suggests otherwise.
	.06	Telemetry Downlink Modes	Spacecraft expose modes that control what telemetry is sent and how, real-time channels, recorder playback, beacon/summary only, event-driven reporting, and per-virtual-channel/APID selections. By switching modes or editing the associated parameters (rates, filters, playback queues, index ranges), an adversary can thin, defer, or reroute observability. Typical effects include suppressing high-rate engineering streams in favor of minimal beacons, delaying playback of time periods of interest, replaying benign segments, or redirecting packets to alternate virtual channels that are not routinely monitored. Telemetry continues to flow, but it no longer reflects the activity the operators need to see.
	.07	Cryptographic Modes	Many missions separate authentication from confidentiality and allow on-orbit selection of algorithms, keys, profiles, or “crypto off/clear” states. Adversaries manipulate these mode controls and selectors to desynchronize ground and space or to hide content: flipping to a profile that the ground is not using, requesting clear telemetry while maintaining authenticated uplink, or rotating key IDs so frames validate internally but appear undecodable to external tools. Mode indicators and status words can also be biased so ground displays show expected settings while the link actually operates under attacker-chosen parameters, masking command and data exchanges within normal-looking traffic.
	.08	Received Commands	Spacecraft typically maintain histories of accepted, rejected, and executed commands, buffers, logs, or file records that can be downlinked on demand or periodically. An adversary conceals activity by editing or pruning these artifacts: removing entries, altering opcodes or arguments, rewriting timestamps and source identifiers, rolling logs early, or repopulating with benign-looking commands to balance counters. Related acknowledgments and event records may be suppressed or reclassified so cross-checks appear consistent. After manipulation, the official command history shows a plausible narrative that omits or mischaracterizes the adversary’s actions.
	.09	System Clock for Evasion	The adversary biases the spacecraft’s authoritative time so that telemetry, event logs, and command histories appear shifted or inconsistent. By writing clock registers, altering disciplining sources (e.g., GNSS vs. free-running oscillator), or tweaking distribution services and offsets, they can make stored commands execute “earlier” or “later” on the timeline and misalign acknowledgments with actual actions. Downlinked frames still carry plausible timestamps near packet headers, but those stamps no longer reflect when data was produced, complicating reconstruction of sequences and masking causality during incident analysis.
	.10	GPS Ephemeris	A satellite with a GPS receiver can use ephemeris data from GPS satellites to estimate its own position in space. A hostile actor could spoof the GPS signals to cause erroneous calculations of the satellite’s position. The received ephemeris data is often telemetered and can be monitored for indications of GPS spoofing. Reception of ephemeris data that changes suddenly without a reasonable explanation (such as a known GPS satellite handoff), could provide an indication of GPS spoofing and warrant further analysis. Threat actors could also change the course of the vehicle and falsify the telemetered data to temporarily convince ground operators the vehicle is still on a proper course.
	.11	Watchdog Timer (WDT) for Evasion	By modifying watchdog parameters or who “pets” them, an adversary shapes what evidence survives. Extending or disabling timeouts allows long-running processes to operate without forced resets that would expose abnormal CPU or power usage; conversely, shortening windows or relocating the petting source to a low-level ISR can induce frequent resets that wipe volatile traces, break correlation in logs, and explain anomalies as “spurious reboots.” In both directions, the watchdog becomes a timing tool for hiding activity rather than a guardrail against it.
	.12	Poison AI/ML Training for Evasion	When security monitoring relies on AI/ML (e.g., anomaly detection on telemetry, RF fingerprints, or command semantics), the training data itself is a target. Data-poisoning introduces crafted examples or labels so the learned model embeds false associations, treating attacker behaviors as normal, or flagging benign patterns instead. Variants include clean-label backdoors keyed to subtle triggers, label flipping that shifts decision boundaries, and biased sampling that suppresses rare-but-critical signatures. Models trained on tainted corpora are later deployed as routine updates; once in service, the adversary presents inputs containing the trigger or profile they primed, and the detector omits or downranks the very behaviors that would reveal the intrusion.
DE-0005		Subvert Protections via Safe-Mode	The adversary exploits the spacecraft’s recovery posture to bypass controls that are stricter in nominal operations. During safe-mode, vehicles often accept contingency dictionaries, relax rate/size and timetag checks, activate alternate receivers or antennas, and emit reduced or summary telemetry. By timing actions to this state, or deliberately inducing it, the attacker issues maintenance-looking edits, loads, or mode changes that proceed under broadened acceptance while downlink visibility is thinned. Unauthorized activity blends with anomaly response, evading both automated safeguards and operator suspicion.
DE-0006		Modify Whitelist	Threat actors may target whitelists on the spacecrafts as a means to execute and/or hide malicious processes/programs. Whitelisting is a common technique used on traditional IT systems but has also been used on spacecrafts. Whitelisting is used to prevent execution of unknown or potentially malicious software. However, this technique can be bypassed if not implemented correctly but threat actors may also simply attempt to modify the whitelist outright to ensure their malicious software will operate on the spacecraft that utilizes whitelisting.
DE-0007		Evasion via Rootkit	A rootkit hides malicious activity by interposing on reporting paths after the system has booted. In flight contexts this includes patching flight software APIs, kernel syscalls, message queues, and telemetry publishers so task lists, counters, health channels, and event severities are falsified before downlink. Command handlers can be hooked to suppress evidence of certain opcodes or sources; recorder catalogs and file listings can be rewritten on the fly; and housekeeping can be biased to show nominal temperatures, currents, or voltages while actions proceed. The defining feature is runtime concealment: the observability surfaces operators rely on are altered to present a curated, benign narrative.
DE-0008		Evasion via Bootkit	A bootkit hides activity by running first and shaping what higher layers will later observe. Positioned in boot ROM handoff or early loaders, it can select or patch images in memory, alter device trees and driver tables, seed forged counters and timestamps, and preconfigure telemetry/crypto modes so subsequent components launch into a reality curated by the attacker. Because integrity and logging mechanisms are initialized afterward, the resulting view of processes, files, and histories reflects the bootkit’s choices, allowing long-term evasion that persists across resets and mode transitions.
DE-0010		Overflow Audit Log	The adversary hides activity by exhausting finite on-board logging and telemetry buffers so incriminating events are overwritten before they can be downlinked. Spacecraft typically use ring buffers with severity filters, per-subsystem quotas, and scheduled dump windows; by generating bursts of benign but high-frequency events (file listings, status queries, low-severity housekeeping, repeated mode toggles) or by provoking chatter from chatty subsystems, the attacker accelerates rollover. Variants target recorder indexes and event catalogs so new entries displace older ones, or they align floods with known downlink gaps and pass handovers when retention is shortest. To analysts on the ground, logs appear present but incomplete, showing a plausible narrative that omits the very interval when unauthorized commands or updates occurred.
LM-0001		Hosted Payload	The adversary pivots through the host–payload boundary to reach additional subsystems. Hosted payloads exchange power, time, housekeeping, and data with the bus via defined gateways (e.g., SpaceWire, 1553, Ethernet) and often support file services, table loads, and command dictionaries distinct from the host’s. A foothold on the payload can be used to inject traffic through the gateway processor, request privileged services (time/ephemeris distribution, firmware loads), or ride shared backplanes where payload traffic is bridged into C&DH networks. In some designs, payload processes execute on host compute or expose maintenance modes that temporarily widen access, creating paths from the payload into attitude, power, storage, or recorder resources. The movement is transitive: compromise a co-resident unit, then traverse the trusted interface that already exists for mission operations.
LM-0002		Exploit Lack of Bus Segregation	On flat architectures, where remote terminals, subsystems, and payloads share a common bus with minimal partitioning, any node that can transmit may influence many others. An attacker leverages this by forging message IDs or terminal addresses, replaying actuator/sensor frames, seizing or imitating bus-controller roles, or abusing gateway bridges that forward traffic between links (e.g., 1553↔SpaceWire/CAN). Because consumers often act on the latest valid-looking message, crafted traffic from one compromised device can reconfigure peers, toggle power domains, or write persistent parameters. Weak role enforcement and broadcast semantics allow privilege escalation from a peripheral to effective system-wide influence, turning the shared medium into a highway for further compromise.
LM-0003		Constellation Hopping via Crosslink	In networks where vehicles exchange data over inter-satellite links, a compromise on one spacecraft becomes a springboard to others. The attacker crafts crosslink traffic, routing updates, service advertisements, time/ephemeris distribution, file or tasking messages, that appears to originate from a trusted neighbor and targets gateway functions that bridge crosslink traffic into command/data paths. Once accepted, those messages can queue procedures, deliver configuration/table edits, or open file transfer sessions on adjacent vehicles. In mesh or hub-and-spoke constellations, this enables “hop-by-hop” spread: a single foothold uses shared trust and protocol uniformity to reach additional satellites without contacting the ground segment.
LM-0004		Visiting Vehicle Interface(s)	Docking, berthing, or short-duration attach events create high-trust, high-bandwidth connections between vehicles. During these operations, automatic sequences verify latches, exchange status, synchronize time, and enable umbilicals that carry data and power; maintenance tools may also push firmware or tables across the interface. An attacker positioned on the visiting vehicle can exploit these handshakes and service channels to inject commands, transfer files, or access bus gateways on the host. Because many actions are expected “just after dock,” malicious traffic can ride the same procedures that commission the interface, allowing lateral movement from the visiting craft into the target spacecraft’s C&DH, payload, or support subsystems.
EXF-0001		Replay	The adversary re-sends previously valid commands or procedures to cause the spacecraft to transmit data again, then captures the resulting downlink. Typical targets are recorder playbacks, payload product dumps, housekeeping snapshots, or file directory listings. By aligning replays with geometry (e.g., when the satellite is in view of actor-controlled apertures) and with acceptance conditions (counters, timetags, mode), the attacker induces legitimate transmissions that appear routine to operators. Variants include selectively replaying index ranges to fetch only high-value intervals, reissuing subscription/telemetry-rate changes to increase data volume, or queueing playbacks that fire during later passes when interception is feasible.

Space Threats Addressed by Countermeasure

ID	Description
SV-IT-2	Unauthorized modification or corruption of data
SV-MA-2	Heaters and flow valves of the propulsion subsystem are controlled by electric signals so cyberattacks against these signals could cause propellant lines to freeze, lock valves, waste propellant or even put in de-orbit or unstable spinning
SV-AV-4	Attacking the scheduling table to affect tasking
SV-IT-5	Onboard control procedures (i.e., ATS/RTS) that execute a scripts/sets of commands
SV-MA-3	Attacks on critical software subsystems Attitude Determination and Control (AD&C) subsystem determines and controls the orientation of the satellite. Any cyberattack that could disrupt some portion of the control loop - sensor data, computation of control commands, and receipt of the commands would impact operations Telemetry, Tracking and Commanding (TT&C) subsystem provides interface between satellite and ground system. Computations occur within the RF portion of the TT&C subsystem, presenting cyberattack vector Command and Data Handling (C&DH) subsystem is the brains of the satellite. It interfaces with other subsystems, the payload, and the ground. It receives, validate, decodes, and sends commands to other subsystems, and it receives, processes, formats, and routes data for both the ground and onboard computer. C&DH has the most cyber content and is likely the biggest target for cyberattack. Electrical Power Subsystem (EPS) provides, stores, distributes, and controls power on the satellite. An attack on EPS could disrupt, damage, or destroy the satellite.
SV-SP-1	Exploitation of software vulnerabilities (bugs); Unsecure code, logic errors, etc. in the FSW.
SV-SP-3	Introduction of malicious software such as a virus, worm, Distributed Denial-Of-Service (DDOS) agent, keylogger, rootkit, or Trojan Horse
SV-SP-6	Software reuse, COTS dependence, and standardization of onboard systems using building block approach with addition of open-source technology leads to supply chain threat
SV-SP-9	On-orbit software updates/upgrades/patches/direct memory writes. If TT&C is compromised or MOC or even the developer's environment, the risk exists to do a variation of a supply chain attack where after it is in orbit you inject malicious code
SV-AC-6	Three main parts of S/C. CPU, memory, I/O interfaces with parallel and/or serial ports. These are connected via busses (i.e., 1553) and need segregated. Supply chain attack on CPU (FPGA/ASICs), supply chain attack to get malware burned into memory through the development process, and rogue RTs on 1553 bus via hosted payloads are all threats. Security or fault management being disabled by non-mission critical or payload; fault injection or MiTM into the 1553 Bus - China has developed fault injector for 1553 - this could be a hosted payload attack if payload has access to main 1553 bus; One piece of FSW affecting another. Things are not containerized from the OS or FSW perspective;
SV-AV-2	Satellites base many operations on timing especially since many operations are automated. Cyberattack to disrupt timing/timers could affect the vehicle (Time Jamming / Time Spoofing)
SV-AV-3	Affect the watchdog timer onboard the satellite which could force satellite into some sort of recovery mode/protocol
SV-IT-3	Compromise boot memory
SV-IT-4	Cause bit flip on memory via single event upsets
SV-MA-8	Payload (or other component) is told to constantly sense or emit or run whatever mission it had to the point that it drained the battery constantly / operated in a loop at maximum power until the battery is depleted.
SV-SP-7	Software can be broken down into three levels (operating system and drivers’ layer, data handling service layer, and the application layer). Highest impact on system is likely the embedded code at the BIOS, kernel/firmware level. Attacking the on-board operating systems. Since it manages all the programs and applications on the computer, it has a critical role in the overall security of the system. Since threats may occur deliberately or due to human error, malicious programs or persons, or existing system vulnerability mitigations must be deployed to protect the OS.
SV-AV-5	Using fault management system against you. Understanding the fault response could be leveraged to get satellite in vulnerable state. Example, safe mode with crypto bypass, orbit correction maneuvers, affecting integrity of TLM to cause action from ground, or some sort of RPO to cause S/C to go into safe mode;
SV-AV-6	Complete compromise or corruption of running state
SV-DCO-1	Not knowing that you were attacked, or attack was attempted
SV-AC-1	Attempting access to an access-controlled system resulting in unauthorized access
SV-IT-1	Communications system spoofing resulting in denial of service and loss of availability and data integrity
SV-AV-1	Communications system jamming resulting in denial of service and loss of availability and data integrity

Sample Requirements

SPARTA ID	Requirement	Rationale/Additional Guidance/Notes
SPR-7	The [organization] shall document and design a security architecture using a defense-in-depth approach that allocates the [organization]s defined safeguards to the indicated locations and layers: [Examples include: operating system abstractions and hardware mechanisms to the separate processors in the platform, internal components, and the FSW].{SV-MA-6}{CA-9,PL-7,PL-8,PL-8(1),SA-8(3),SA-8(4),SA-8(7),SA-8(9),SA-8(11),SA-8(13),SA-8(19),SA-8(29),SA-8(30)}	Spacecraft security cannot rely on a single control; layered defenses reduce the likelihood of catastrophic compromise. Documenting safeguard allocation across hardware, OS, firmware, and FSW ensures coverage across attack surfaces. This supports resiliency against both cyber intrusion and supply chain weaknesses. Clear documentation enables verification and independent assessment.
SPR-8	The [organization] shall ensure that the allocated security safeguards operate in a coordinated and mutually reinforcing manner.{SV-MA-6}{CA-7(5),PL-7,PL-8(1),SA-8(19)}	Independent controls that operate in isolation may create security gaps or conflicting behaviors. Coordinated safeguards ensure that encryption, authentication, partitioning, and monitoring functions reinforce each other rather than undermine availability or safety. This reduces bypass risk and improves fault/cyber response integration. Cohesive operation is essential for resilient mission assurance.
SPR-9	The [organization] shall implement a security architecture and design that provides the required security functionality, allocates security controls among physical and logical components, and integrates individual security functions, mechanisms, and processes together to provide required security capabilities and a unified approach to protection.{SV-MA-6}{PL-7,SA-2,SA-8,SA-8(1),SA-8(2),SA-8(3),SA-8(4),SA-8(5),SA-8(6),SA-8(7),SA-8(9),SA-8(11),SA-8(13),SA-8(19),SA-8(29),SA-8(30),SC-32,SC-32(1)}	Security functionality must be intentionally distributed across physical and logical components rather than bolted on post-design. A unified architecture prevents inconsistent enforcement, duplicated controls, or unprotected interfaces. Integrated design reduces attack surface and improves verification of mission-critical protections.
SPR-14	The [spacecraft] shall authenticate the ground station (and all commands) and other spacecraft before establishing remote connections using bidirectional authentication that is cryptographically based.{SV-AC-1,SV-AC-2}{AC-3,AC-17,AC-17(2),AC-17(10),AC-18(1),AC-20,IA-3(1),IA-4,IA-4(9),IA-7,IA-9,SA-8(18),SA-8(19),SA-9(2),SC-7(11),SC-16(1),SC-16(2),SC-16(3),SC-23(3),SI-3(9)}	Authorization can include embedding opcodes in command strings, using trusted authentication protocols, identifying proper link characteristics such as emitter location, expected range of receive power, expected modulation, data rates, communication protocols, beamwidth, etc.; and tracking command counter increments against expected values.
SPR-15	The [spacecraft] shall implement cryptographic mechanisms to identify and reject wireless transmissions that are deliberate attempts to achieve imitative or manipulative communications deception based on signal parameters.{SV-AV-1,SV-IT-1}{AC-3,AC-20,SA-8(19),SC-8(1),SC-23(3),SC-40(3),SI-4(13),SI-4(24),SI-4(25),SI-10(6)}	Adversaries may attempt imitative RF signals to inject commands or manipulate spacecraft behavior. Signal parameter validation (modulation, power, timing, waveform characteristics) strengthens command authentication beyond cryptographic validation alone. This helps mitigate spoofing, replay, and rogue emitter attacks. RF-layer validation complements cryptographic controls.
SPR-16	The [spacecraft] shall ensure that processes reusing a shared system resource (e.g., registers, main memory, secondary storage) do not have access to information (including encrypted representations of information) previously stored in that resource after formal release, by clearing or zeroizing the resource prior to reuse.{SV-AC-6}{AC-3,PM-32,SA-8(2),SA-8(5),SA-8(6),SA-8(19),SC-4,SI-3}	Residual data in memory or registers can create covert channels or leakage paths between partitions. Zeroization prevents recovery of sensitive data by subsequent processes. This mitigates cross-domain leakage and memory scraping attacks. Clearing encrypted remnants is equally important to prevent cryptanalytic exploitation.
SPR-20	The [spacecraft] shall prevent use of a mode of operations where cryptography on the TT&C link can be disabled; encryption and authentication shall remain enabled even when automated access control mechanisms are overridden.{SV-AC-1,SV-CF-1,SV-CF-2}{AC-3(10),SA-8(18),SA-8(19),SC-16(2),SC-16(3),SC-40,SC-40(4)}	Emergency or override modes often become attack vectors if protections are weakened. Cryptography must remain enforced even during safe-mode or degraded operations. Removing encryption capability creates a single-point catastrophic exposure. Persistent protection ensures no operational shortcut undermines mission assurance.
SPR-22	The [spacecraft] shall implement boundary protections to separate bus, communications, and payload components supporting their respective functions.{SV-AC-6}{AC-3(3),AC-3(4),CA-9,SA-8(3),SA-8(14),SA-8(18),SA-8(19),SA-17(7),SC-2,SC-2(2),SC-7(13),SC-7(21),SC-7(29),SC-16(3),SC-32,SI-3,SI-4(13),SI-4(25)}	Flat architectures allow compromise of one subsystem to impact all others. Segregated boundaries reduce lateral movement and mission degradation. Isolation ensures payload compromise does not impact TT&C or bus control. This supports containment and survivability.
SPR-23	The [spacecraft] shall isolate mission critical functionality from non-mission critical functionality.{SV-AC-6}{AC-3(3),AC-3(4),CA-9,SA-8(3),SA-8(19),SA-17(7),SC-2,SC-3,SC-3(4),SC-7(13),SC-7(29),SC-32,SC-32(1),SI-3,SI-7(10),SI-7(12)}	Non-critical functions often expand attack surface. Isolation prevents less-trusted components from affecting propulsion, attitude control, or power systems. This reduces cascading failure risk under compromise. Mission-critical systems must maintain operational continuity.
SPR-25	The [spacecraft] shall prevent unauthorized access to system resources by employing an efficient capability based object model that supports both confinement and revocation of these capabilities when the platform security deems it necessary.{SV-AC-6}{AC-3(8),IA-4(9),PM-32,SA-8(2),SA-8(5),SA-8(6),SA-8(18),SA-8(19),SC-2(2),SC-4,SC-16,SC-32,SI-3}	Capability models restrict access to explicit, revocable tokens of authority. This enforces least privilege and supports dynamic revocation under threat conditions. Confinement reduces damage radius of compromised processes. Revocation capability enables adaptive cyber response.
SPR-28	The [spacecraft] shall provide the capability to enter the platform into a known good, operational cyber-safe mode from a tamper-resistant, configuration-controlled (“gold”) image that is authenticated as coming from an acceptable supplier, and has its integrity verified. The [spacecraft] shall refresh only from cryptographically authenticated [organization]-approved sources.{SV-AV-5,SV-AV-6,SV-AV-7}{CP-10(6),CP-12,CP-13,IR-4(3),SA-8(16),SA-8(19),SA-8(21),SA-8(24),SI-13,SI-17}	Cyber-safe mode is an operating mode of a spacecraft during which all nonessential systems are shut down and the spacecraft is placed in a known good state using validated software and configuration settings. Within cyber-safe mode authentication and encryption should still be enabled. The spacecraft should be capable of reconstituting firmware and SW functions to preattack levels to allow for the recovery of functional capabilities. This can be performed by self-healing, or the healing can be aided from the ground. However, the spacecraft needs to have the capability to replan, based on available equipment still available after a cyberattack. The goal is for the vehicle to resume full mission operations. If not possible, a reduced level of mission capability should be achieved.
SPR-29	The [spacecraft] shall enter cyber-safe mode software/configuration should be stored onboard the spacecraft in memory with hardware-based controls and should not be modifiable.{CP-10(6),CP-13,SA-8(16),SA-8(19),SA-8(21),SA-8(24),SI-17}
SPR-30	The [spacecraft] shall fail to a known secure state for failures during initialization, and aborts preserving information necessary to return to operations in failure.{SV-AV-5,SV-AV-6,SV-AV-7}{CP-10(6),CP-13,SA-8(16),SA-8(19),SA-8(24),SC-24,SI-13,SI-17}
SPR-32	The [spacecraft] shall provide or support the capability for recovery and reconstitution to a known state after a disruption, compromise, or failure.{SV-AV-5,SV-AV-6,SV-AV-7}{CP-4(4),CP-10,CP-10(4),CP-10(6),CP-13,IR-4,IR-4(1),SA-8(16),SA-8(19),SA-8(24)}
SPR-33	The [spacecraft] shall utilize TRANSEC. TRANSEC shall be implemented and verified as a distinct layer in coordination with Traffic Flow Security and RF anti‑fingerprinting.{SV-AV-1}{CP-8,RA-5(4),SA-8(18),SA-8(19),SC-8(1),SC-8(4),SC-16,SC-16(1),SC-16(2),SC-16(3),SC-40,SC-40(4)}	Transmission Security (TRANSEC) is used to ensure the availability of transmissions and limit intelligence collection from the transmissions. TRANSEC is secured through burst encoding, frequency hopping, or spread spectrum methods where the required pseudorandom sequence generation is controlled by a cryptographic algorithm and key. Such keys are known as transmission security keys (TSK). The objectives of transmission security are low probability of interception (LPI), low probability of detection (LPD), and antijam which means resistance to jamming (EPM or ECCM).
SPR-34	The [spacecraft] shall recover to a known cyber-safe state when an anomaly is detected.{IR-4,IR-4(1),SA-8(16),SA-8(19),SA-8(21),SA-8(24),SI-3,SI-4(7),SI-10(6),SI-13,SI-17}
SPR-35	The [spacecraft] shall perform an orderly, controlled system shut-down to a known cyber-safe state upon receipt of a termination command or condition.{PE-11,PE-11(1),SA-8(16),SA-8(19),SA-8(24),SI-17}
SPR-36	The [spacecraft] shall operate securely in off-nominal power conditions, including loss of power and spurious power transients.{SV-AV-6,SV-MA-2}{PE-11,PE-11(1),SA-8(16),SA-8(19),SI-13,SI-17}	Power anomalies may induce undefined states exploitable by attackers. Cryptographic and security mechanisms must not degrade into insecure configurations during brownout or transient conditions. This mitigates fault-induced bypass attacks. Resilient operation preserves trust chain continuity.
SPR-41	The [spacecraft] shall maintain a separate execution domain for each executing process.{SV-AC-6}{SA-8(14),SA-8(19),SC-2(2),SC-7(21),SC-39,SI-3}	Process isolation prevents one compromised task from impacting others. Separate execution domains mitigate memory corruption and privilege escalation. This strengthens containment of malicious code. Deterministic isolation enhances both safety and cybersecurity.
SPR-43	The [spacecraft] shall initialize the platform to a known safe state.{SA-8(19),SA-8(23),SA-8(24),SI-17}
SPR-46	The [spacecraft] shall monitor [Program‑defined telemetry points] for malicious commanding attempts and alert ground operators upon detection.{SV-AC-2,SV-IT-1,SV-DCO-1}{AC-17,AC-17(1),AC-17(10),AU-3(1),RA-10,SC-7,SC-16,SC-16(2),SC-16(3),SI-3(8),SI-4,SI-4(1),SI-4(13),SI-4(24),SI-4(25),SI-10(6)}	Telemetry-based detection enables identification of anomalous command patterns, replay attempts, and injection attacks. Early detection allows rapid containment before mission impact escalates. Onboard monitoring is critical when ground latency limits intervention. This supports proactive defense.
SPR-47	The [spacecraft] shall implement relay and replay-resistant authentication mechanisms for establishing a remote connection.{SV-AC-1,SV-AC-2}{AC-3,IA-2(8),IA-2(9),SA-8(18),SC-8(1),SC-16(1),SC-16(2),SC-23(3),SC-40(4)}	Replay attacks can reuse valid command packets to manipulate spacecraft behavior. Freshness checks, nonces, and sequence enforcement prevent reuse of captured transmissions. Relay resistance mitigates man-in-the-middle exploitation. This protects command integrity over RF links.
SPR-48	The [spacecraft] shall implement cryptographic mechanisms to protect the integrity of audit information and audit tools.{SV-DCO-1}{AU-9(3),RA-10,SC-8(1),SI-3,SI-3(10),SI-4(24)}	Audit logs are essential for attribution and forensic analysis. If adversaries can modify audit data, detection and recovery become unreliable. Cryptographic integrity protections preserve evidentiary value.
SPR-53	The [organization] shall employ automated tools that provide notification to ground operators upon discovering discrepancies during integrity verification.{CM-3(5),CM-6,IR-6,IR-6(2),SA-8(21),SC-51,SI-3,SI-4(7),SI-4(12),SI-4(24),SI-7(2)}
SPR-54	The [spacecraft] shall retain the capability to update/upgrade operating systems while on-orbit.{SV-SP-7}{SA-4(5),SA-8(8),SA-8(31),SA-10(2),SI-3}	The operating system updates should be performed using multi-factor authorization and should only be performed when risk of compromise/exploitation of identified vulnerability outweighs the risk of not performing the update.
SPR-55	The [spacecraft] shall provide cyber threat status to the ground segment for the Defensive Cyber Operations team, per the governing specification.{SV-DCO-1}{IR-5,PM-16,PM-16(1),RA-3(3),RA-10,SI-4,SI-4(1),SI-4(24),SI-7(7)}	The future space enterprises will include full-time Cyber Defense teams supporting space mission systems. Their work is currently focused on the ground segment but may eventually require specific data from the space segment for their successful operation. This requirement is a placeholder to ensure that any DCO-related requirements are taken into consideration for this document.
SPR-56	The [spacecraft] shall provide automated onboard mechanisms that integrate audit review, analysis, and reporting processes to support mission processes for investigation and response to suspicious activities to determine the attack class in the event of a cyber attack.{SV-DCO-1}{AU-6(1),IR-4,IR-4(1),IR-4(12),IR-4(13),PM-16(1),RA-10,SA-8(21),SA-8(22),SC-5(3),SI-3,SI-3(10),SI-4(7),SI-4(24),SI-7(7)}	* Identifying the class (e.g., exfiltration, Trojans, etc.), nature, or effect of cyberattack (e.g., exfiltration, subverted control, or mission interruption) is necessary to determine the type of response. The first order of identification may be to determine whether the event is an attack or a non-threat event (anomaly). The objective requirement would be to predict the impact of the detected signature. * Unexpected conditions can include RF lockups, loss of lock, failure to acquire an expected contact and unexpected reports of acquisition, unusual AGC and ACS control excursions, unforeseen actuator enabling's or actions, thermal stresses, power aberrations, failure to authenticate, software or counter resets, etc. Mitigation might include additional TMONs, more detailed AGC and PLL thresholds to alert operators, auto-capturing state snapshot images in memory when unexpected conditions occur, signal spectra measurements, and expanded default diagnostic telemetry modes to help in identifying and resolving anomalous conditions.
SPR-57	The [spacecraft] shall monitor and collect all onboard cyber- data (from multiple system components), including identification of potential attacks and information about the attack for subsequent analysis.{SV-DCO-1}{AC-6(9),AC-20,AC-20(1),AU-2,AU-12,IR-4,IR-4(1),RA-10,SI-3,SI-3(10),SI-4,SI-4(1),SI-4(2),SI-4(7),SI-4(24)}	The spacecraft will monitor and collect data that provides accountability of activity occurring onboard the spacecraft. Due to resource limitations on the spacecraft, analysis must be performed to determine which data is critical for retention and which can be filtered. Full system coverage of data and actions is desired as an objective; it will likely be impractical due to the resource limitations. “Cyber-relevant data” refers to all data and actions deemed necessary to support accountability and awareness of onboard cyber activities for the mission. This would include data that may indicate abnormal activities, critical configuration parameters, transmissions on onboard networks, command logging, or other such data items. This set of data items should be identified early in the system requirements and design phase. Cyber-relevant data should support the ability to assess whether abnormal events are unintended anomalies or actual cyber threats. Actual cyber threats may rarely or never occur, but non-threat anomalies occur regularly. The ability to filter out cyber threats for non-cyber threats in relevant time would provide a needed capability. Examples could include successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels).
SPR-58	The [spacecraft] shall generate cyber related audit records containing information that establishes what type of event occurred, when the event occurred, where the event occurred, the source of the event, and the outcome of the event. For privileged or hazardous commands, the audit record shall include the approver identifiers and the command identifier.{SV-DCO-1}{AU-3,AU-3(1),AU-12,IR-4,IR-4(1),RA-10,SI-3,SI-3(10),SI-4(7),SI-4(24)}	Detailed audit records are essential for attribution, anomaly detection, and post-incident forensic reconstruction. Capturing what occurred, when, where, and by whom enables rapid differentiation between system fault and adversarial activity. Including approver identifiers for privileged or hazardous commands strengthens accountability and insider threat mitigation. Without complete audit context, recovery and containment decisions may be delayed or misinformed.
SPR-59	The [spacecraft] shall attribute cyber attacks and identify unauthorized use of the platform by downlinking onboard cyber information to the mission ground station within [Program‑defined time ≤ 3 minutes].{SV-DCO-1,SV-IT-1,SV-IT-2}{AU-4(1),IR-4,IR-4(1),IR-4(12),IR-4(13),RA-10,SA-8(22),SI-3,SI-3(10),SI-4,SI-4(5),SI-4(7),SI-4(12),SI-4(24)}	Rapid transmission of cyber-relevant telemetry supports near-real-time ground-based fusion and correlation with enterprise security events. Delayed reporting increases risk of adversary persistence or mission degradation. Early attribution enables containment actions before cascading effects occur. Defined timeliness ensures detection capability aligns with operational tempo.
SPR-60	The [spacecraft] shall integrate cyber related detection and responses with existing fault management capabilities to ensure tight integration between traditional fault management and cyber intrusion detection and prevention.{SV-DCO-1}{AU-6(4),IR-4,IR-4(1),RA-10,SA-8(21),SA-8(26),SC-3(4),SI-3,SI-3(10),SI-4(7),SI-4(13),SI-4(16),SI-4(24),SI-4(25),SI-7(7),SI-13}	The onboard IPS system should be integrated into the existing onboard spacecraft fault management system (FMS) because the FMS has its own fault detection and response system built in. SV corrective behavior is usually limited to automated fault responses and ground commanded recovery actions. Intrusion prevention and response methods will inform resilient cybersecurity design. These methods enable detected threat activity to trigger defensive responses and resilient SV recovery.
SPR-61	The [spacecraft] shall protect information obtained from logging/intrusion-monitoring from unauthorized access, modification, and deletion.{SV-DCO-1}{AU-9,AU-9(3),RA-10,SI-4(7),SI-4(24)}	Monitoring data is a high-value target for attackers seeking to evade detection or erase traces of compromise. Protecting log integrity preserves evidentiary value and detection continuity. Unauthorized modification or deletion could mask malicious behavior or delay response. Cryptographic protection and access controls ensure monitoring mechanisms cannot be silently disabled.
SPR-62	The [spacecraft] shall enter a cyber-safe mode when conditions that threaten the platform are detected, enters a cyber-safe mode of operation with restrictions as defined based on the cyber-safe mode.{SV-AV-5,SV-AV-6,SV-AV-7}{CP-10(6),CP-12,CP-13,IR-4,IR-4(1),IR-4(3),PE-10,RA-10,SA-8(16),SA-8(21),SA-8(24),SI-3,SI-4(7),SI-13,SI-17}	Cyber-safe mode provides a deterministic fallback posture when compromise or anomalous conditions threaten mission integrity. Restricting non-essential functions reduces attack surface and prevents further propagation of malicious activity. Defined restrictions ensure predictable behavior under cyber stress conditions. This supports survivability and controlled recovery rather than uncontrolled degradation.
SPR-63	The [spacecraft] shall be able to locate the onboard origin of a cyber attack and alert ground operators within [Program‑defined time ≤ 3 minutes].{SV-DCO-1}{IR-4,IR-4(1),IR-4(12),IR-4(13),RA-10,SA-8(22),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(7),SI-4(12),SI-4(16),SI-4(24)}	The origin of any attack onboard the vehicle should be identifiable to support mitigation. At the very least, attacks from critical element (safety-critical or higher-attack surface) components should be locatable quickly so that timely action can occur.
SPR-64	The [spacecraft] shall detect and deny unauthorized outgoing communications posing a threat to the spacecraft.{SV-DCO-1}{IR-4,IR-4(1),RA-5(4),RA-10,SC-7(9),SC-7(10),SI-4,SI-4(1),SI-4(4),SI-4(7),SI-4(11),SI-4(13),SI-4(24),SI-4(25)}	Outbound communications may indicate data exfiltration, covert channels, or compromised subsystem behavior. Monitoring and blocking unauthorized egress prevents leakage of mission data or cryptographic material. Many attacks rely on command-and-control or data extraction channels; egress control disrupts this persistence mechanism. Outbound traffic should be as tightly controlled as inbound command paths.
SPR-65	The [spacecraft] shall select and execute safe countermeasures against cyber attacks prior to entering cyber-safe mode.{SV-DCO-1}{IR-4,RA-10,SA-8(21),SA-8(24),SI-4(7),SI-17}	These countermeasures are a ready supply of options to triage against the specific types of attack and mission priorities. Minimally, the response should ensure vehicle safety and continued operations. Ideally, the goal is to trap the threat, convince the threat that it is successful, and trace and track the attacker exquisitely—with or without ground aiding. This would support successful attribution and evolving countermeasures to mitigate the threat in the future. “Safe countermeasures” are those that are compatible with the system’s fault management system to avoid unintended effects or fratricide on the system." These countermeasures are likely executed prior to entering into a cyber-safe mode.
SPR-66	The [spacecraft] shall be designed and configured so that encrypted communications traffic and data is visible to on-board security monitoring tools.{SV-DCO-1}{RA-10,SA-8(21),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(10),SI-4(13),SI-4(24),SI-4(25)}	Encryption must not blind onboard intrusion detection capabilities. Security tools require access to sufficient context (pre-encryption or post-decryption inspection points) to detect malicious patterns. Without visibility, encrypted channels become covert channels. Proper architectural placement ensures both confidentiality and detectability are preserved.
SPR-67	The [spacecraft] shall be designed and configured so that spacecraft memory can be monitored by the on-board intrusion detection/prevention capability.{SV-DCO-1}{RA-10,SA-8(21),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(24),SI-16}	Many spacecraft attacks target memory corruption, firmware modification, or unauthorized process injection. Monitoring memory state enables detection of tampering, abnormal writes, or execution anomalies. Memory visibility supports early detection of wiper malware or boot-level compromise. This is essential for protecting deterministic flight software environments.
SPR-68	The [spacecraft] shall have on-board intrusion detection/prevention system that monitors the mission critical components or systems.{SV-AC-1,SV-AC-2,SV-MA-4}{RA-10,SC-7,SI-3,SI-3(8),SI-4,SI-4(1),SI-4(7),SI-4(13),SI-4(24),SI-4(25),SI-10(6)}	The mission critical components or systems could be GNC/Attitude Control, C&DH, TT&C, Fault Management.
SPR-69	The [spacecraft] shall alert in the event of the audit/logging processing failures.{SV-DCO-1}{AU-5,AU-5(1),AU-5(2),SI-3,SI-4,SI-4(1),SI-4(7),SI-4(12),SI-4(24)}	Failure of logging mechanisms may signal active tampering or resource exhaustion attacks. Immediate alerting ensures loss of visibility does not go unnoticed. Silent failure of audit systems creates blind spots exploitable by adversaries. Monitoring the monitors is critical to resilient detection.
SPR-70	The [spacecraft] shall provide an alert immediately to [at a minimum the mission director, administrators, and security officers] when the following failure events occur: [minimally but not limited to: auditing software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity reaching 95%, 99%, and 100%] of allocated capacity, including security component failover events; alerts shall include component identity, time, and fault reason.{SV-DCO-1}{AU-5,AU-5(1),AU-5(2),SI-4,SI-4(1),SI-4(7),SI-4(12),SI-4(24),SI-7(7)}	Intent is to have human on the ground be alerted to failures. This can be decomposed to SV to generate telemetry and to Ground to alert.
SPR-71	The [spacecraft] shall provide the capability of a cyber “black-box” to capture necessary data for cyber forensics of threat signatures and anomaly resolution when cyber attacks are detected. The [spacecraft] shall automatically route audit events to the alternate audit logging capability upon primary audit failure and shall resynchronize the alternate store to the primary upon recovery.{SV-DCO-1}{AU-5(5),AU-9(2),AU-9(3),AU-12,IR-4(12),IR-4(13),IR-5(1),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(7),SI-4(24),SI-7(7)}	Similar concept of a "black box" on an aircraft where all critical information is stored for post forensic analysis. Black box can be used to record CPU utilization, GNC physical parameters, audit records, memory contents, TT&C data points, etc. The timeframe is dependent upon implementation but needs to meet the intent of the requirement. For example, 30 days may suffice.
SPR-72	The [spacecraft] shall automatically notify ground operators when onboard integrity verification detects discrepancies.{SV-IT-2}{CM-3(5),SA-8(21),SI-3,SI-4(7),SI-4(12),SI-4(24),SI-7(2),SI-7(12)}	Integrity check failures may indicate unauthorized modification, corruption, or hardware faults induced by malicious activity. Automatic notification ensures ground teams can rapidly assess risk and initiate recovery procedures. Delay in reporting increases mission impact. Transparency between onboard detection and ground response is essential for coordinated defense.
SPR-73	The [spacecraft], upon detection of a potential integrity violation, shall provide the capability to [audit the event and alert ground operators].{SV-DCO-1}{CM-3(5),SA-8(21),SI-3,SI-4(7),SI-4(12),SI-4(24),SI-7(8)}	One example would be for bad commands where the system would reject the command and not increment the Vehicle Command Counter (VCC) and include the information in telemetry.
SPR-74	The [organization] shall define the security safeguards that are to be automatically employed when integrity violations are discovered.{SV-IT-2}{CP-2,SA-8(21),SI-3,SI-4(7),SI-4(12),SI-7(5),SI-7(8)}	Predefined safeguards ensure consistent and timely response to detected integrity violations. Ad hoc response increases uncertainty and recovery time. Automated actions may include isolation, reconstitution from gold images, or transition to cyber-safe mode. Defined response paths improve resilience and reduce operator burden during crisis.
SPR-77	The [spacecraft] shall employ the principle of least privilege, allowing only authorized accesses processes which are necessary to accomplish assigned tasks in accordance with system functions.{SV-AC-6}{AC-3,AC-6,AC-6(9),CA-9,CM-5,CM-5(5),CM-5(6),SA-8(2),SA-8(5),SA-8(6),SA-8(14),SA-8(23),SA-17(7),SC-2,SC-7(29),SC-32,SC-32(1),SI-3}	Least privilege limits damage from compromised processes or insider misuse. Processes receive only the minimum access necessary for assigned functions. This reduces lateral movement and privilege escalation pathways. In deterministic spacecraft systems, privilege boundaries must be tightly defined and enforced.
SPR-78	The [spacecraft] shall provide independent mission/cyber critical threads such that any one credible event will not corrupt another mission/cyber critical thread.{SV-AC-6,SV-MA-3,SV-SP-7}{SC-3,SC-32,SC-32(1),SI-3,SI-13}	Segregating mission-critical and cyber-critical execution paths prevents a single failure or compromise from corrupting other critical functions. Thread independence supports fault containment and resilience under attack. This ensures availability of essential functions even during partial compromise. Isolation strengthens both safety and cybersecurity.
SPR-80	The [spacecraft] shall execute procedures for ensuring that security-relevant hardware, software, and firmware updates uploaded are exactly as specified by the gold copies. {SV-SP-9,SV-IT-3,SV-SP-3}{CM-3(5),SA-8(8),SA-8(21),SA-8(31),SA-10(3),SA-10(4),SA-10(6),SI-7(10),SI-7(12)}	Ensuring updates match approved gold copies prevents insertion of malicious or altered firmware/software. Compromise during update processes is a high-impact attack vector. Validation protects the trusted computing baseline. This supports recovery and reconstitution integrity.
SPR-81	The [spacecraft] shall perform an integrity check of software, firmware, and information at startup or during security- events.{SV-IT-3,SV-SP-7,SV-SP-3}{CM-3(5),SA-8(9),SA-8(11),SA-8(21),SI-3,SI-7(1),SI-7(10),SI-7(12),SI-7(17)}	Startup integrity checks detect boot-level compromise or unauthorized modification. Event-triggered checks provide additional protection when anomalies occur. This limits adversary persistence across reboots. Continuous validation reinforces trusted boot regimes.
SPR-86	The [spacecraft] shall perform attestation at each stage of startup and ensure overall trusted boot regime (i.e., root of trust).{SV-IT-3}{SA-8(10),SA-8(11),SA-8(12),SI-7(9),SI-7(10),SI-7(17)}	It is important for the computing module to be able to access a set of functions and commands that it trusts; that is, that it knows to be true. This concept is referred to as root of trust (RoT) and should be included in the spacecraft design. With RoT, a device can always be trusted to operate as expected. RoT functions, such as verifying the device’s own code and configuration, must be implemented in secure hardware (i.e., field programmable gate arrays). By checking the security of each stage of power-up, RoT devices form the first link in a chain of trust that protects the spacecraft
SPR-87	The [spacecraft] shall be configured to provide only essential capabilities.{SV-SP-7,SV-SP-1}{CM-6,CM-7,SA-8(2),SA-8(7),SA-8(13),SA-8(23),SA-8(26),SA-15(5)}	Minimizing enabled functionality reduces attack surface and complexity. Unused services create unnecessary exposure. Essential-only configuration aligns with least functionality principles. This simplifies validation and reduces exploit vectors.
SPR-88	The [spacecraft] shall detect and recover from detected memory errors or transitions to a known cyber-safe state.{SV-IT-4,SV-AV-6}{IR-4,IR-4(1),SA-8(16),SA-8(24),SI-3,SI-4(7),SI-10(6),SI-13,SI-17}	Memory corruption may result from radiation, fault injection, or malicious manipulation. Detection prevents silent data corruption from propagating to mission-critical functions. Recovery mechanisms or safe-state transitions preserve availability. Rapid containment supports mission survivability.
SPR-90	The [organization] shall define and document the transitional state or security-relevant events when the spacecraft will perform integrity checks on software, firmware, and information.{SV-IT-2}{SA-8(21),SI-7(1),SI-7(10),SR-4(4)}	Integrity checks must be executed at well-defined lifecycle transitions (e.g., boot, mode change, update, anomaly). Clear documentation prevents gaps in validation coverage. Transitional state definitions ensure consistent enforcement across mission phases. This supports predictable and auditable trust verification.
SPR-91	The [spacecraft] shall prevent the installation of Flight Software without verification that the component has been digitally signed.{SV-SP-1,SV-SP-3,SV-SP-6,SV-SP-9}{CM-3,CM-3(8),CM-5,CM-5(3),CM-14,SA-8(8),SA-8(31),SA-10(2),SI-3,SI-7(12),SI-7(15)}	Requiring digital signature verification before installing flight software prevents unauthorized, malicious, or tampered code from being introduced into the spacecraft environment. Software supply chain compromise is a high-impact attack vector that can result in persistent control or loss of mission. Cryptographic validation ensures only approved and trusted binaries are executed. This maintains integrity of the trusted computing baseline.
SPR-92	The [spacecraft] shall verify the correct operation of security- software and hardware mechanisms.{SV-DCO-1}{SA-8(21),SI-3,SI-6}	Security controls that fail silently create false confidence and blind spots. Continuous or periodic verification ensures cryptographic modules, access controls, logging mechanisms, and monitoring functions remain operational. Attackers often attempt to disable protections prior to executing malicious actions. Independent health checks preserve detection and enforcement reliability.
SPR-93	The [spacecraft] shall require multi‑factor authorization for: (a) all spacecraft operating system and application updates; (b) updates to task‑scheduling functionality; and (c) creation or update of onboard stored command sequences.{SV-SP-9,SV-SP-11}{AC-3(2),CM-3(8),CM-5,IA-2,PM-12,SA-8(8),SA-8(31),SA-10(2),SI-3(8),SI-7(12),SI-10(6)}	The intent is for multiple checks to be performed prior to executing these SV SW updates. One action is mere act of uploading the SW to the spacecraft. Another action could be check of digital signature (ideal but not explicitly required) or hash or CRC or a checksum. Crypto boxes provide another level of authentication for all commands, including SW updates but ideally there is another factor outside of crypto to protect against FSW updates. Multi-factor authorization could be the "two-man rule" where procedures are in place to prevent a successful attack by a single actor (note: development activities that are subsequently subject to review or verification activities may already require collaborating attackers such that a "two-man rule" is not appropriate).
SPR-97	All [spacecraft] commands which have unrecoverable consequence must have dual authentication prior to command execution. The [spacecraft] shall verify two independent cryptographic approvals prior to execution and shall generate an audit record binding both approver identifiers to the command identifier, time, and outcome.{SV-AC-4,SV-AC-8,SV-AC-2}{AU-9(5),IA-3,IA-4,IA-10,PE-3,PM-12,SA-8(15),SA-8(21),SC-16(2),SC-16(3),SI-3(8),SI-3(9),SI-4(13),SI-4(25),SI-7(12),SI-10(6),SI-13}	Commands with irreversible impact require heightened assurance to prevent catastrophic mission loss. Dual independent cryptographic approvals mitigate insider threat, key compromise, and single-point credential abuse. Binding approver identifiers to the audit trail strengthens accountability and deterrence. This reduces the probability of unauthorized hazardous command execution.
SPR-98	The [spacecraft] shall have a method to ensure the integrity of which have unrecoverable consequence and validate their authenticity before execution.{SV-AC-2,SV-IT-2,SV-IT-1}{AU-9(5),IA-3,IA-4,IA-10,PE-3,PM-12,SA-8(15),SA-8(21),SC-16(2),SC-16(3),SI-3(8),SI-3(9),SI-4(13),SI-4(25),SI-7(12),SI-10(6),SI-13}	Hazardous commands must be cryptographically protected and validated prior to execution. Integrity and authenticity checks prevent replay, modification, or injection of destructive instructions. Without validation, RF interception or command path compromise could result in mission-ending actions. This ensures critical commands are both authorized and unaltered.
SPR-99	The [spacecraft] shall recover from cyber-safe mode to mission operations within 20 minutes.{SV-MA-5}{CP-2(3),CP-2(5),IR-4,SA-8(24)}	Upon conclusion of addressing the threat, the system should be capable of recovering from the minimal survival mode back into a mission-ready state within defined timelines. The intent is to define the timelines and the capability to return back to mission operations.
SPR-100	The [spacecraft] shall monitor [Program defined telemetry points] for malicious commanding attempts.{SV-AC-1,SV-AC-2}{SC-7,AU-3(1),AC-17(1)}	Source from AEROSPACE REPORT NO. TOR-2019-02178 Vehicle Command Counter (VCC) - Counts received valid commands Rejected Command Counter - Counts received invalid commands Command Receiver On/Off Mode - Indicates times command receiver is accepting commands Command Receivers Received Signal Strength - Analog measure of the amount of received RF energy at the receive frequency Command Receiver Lock Modes - Indicates when command receiver has achieved lock on command signal Telemetry Downlink Modes - Indicates when the satellite’s telemetry was transmitting Cryptographic Modes - Indicates the operating modes of the various encrypted links Received Commands - Log of all commands received and executed by the satellite System Clock - Master onboard clock GPS Ephemeris - Indicates satellite location derived from GPS Signals
SPR-106	The [spacecraft] shall provide non-identical methods, or functionally independent methods, for commanding a mission critical function when the software is the sole control of that function.{AC-3(2),SI-3(8),SI-13}
SPR-107	The [spacecraft] shall have multiple uplink paths {SV-AV-1}{CP-8,CP-11,SA-8(18),SC-5,SC-47}	Redundant uplink paths preserve command capability during jamming, interference, or subsystem failure. Availability is a core mission assurance objective. Diverse communication channels reduce single-point failure risk. This enhances resiliency in contested RF environments.
SPR-113	The [spacecraft] shall implement protections against external and internal communications from jamming attempts; verification for anti‑jam shall be distinct from EMI/EPM, EMP/HANE hardness, and anti‑spoof protections.{SV-AV-1}{SC-5,SC-40,SC-40(1)}	Jamming disrupts availability and can mask other malicious activities. Dedicated anti-jam mechanisms preserve command and telemetry continuity. Distinguishing from EMI/EPM and anti-spoof ensures comprehensive RF threat coverage. Availability protections must be validated independently.
SPR-114	The [spacecraft] shall protect external and internal communications from jamming and spoofing attempts; verification for anti‑spoof shall be distinct from EMI/EPM and EMP/HANE hardness.{SV-AV-1,SV-IT-1}{SC-5,SC-40,SC-40(1)}	Can be aided via the Crosslink, S-Band, and L-Band subsystems
SPR-117	The [spacecraft] shall provide the capability to restrict command lock based on geographic location of ground stations.{SV-AC-1}{AC-2(11),IA-10,SI-4(13),SI-4(25)}	This could be performed using command lockout based upon when the spacecraft is over selected regions. This should be configurable so that when conflicts arise, the Program can update. The goal is so the spacecraft won't accept a command when the spacecraft determines it is in a certain region.
SPR-128	The [spacecraft] shall accept hazardous commands only when prerequisite checks are satisfied.{SV-AC-8,SV-AV-5}{AC-17(4),SI-10,SI-10(6)}	Precondition validation ensures hazardous commands are executed only under safe system states. This prevents execution under anomalous or compromised conditions. Independent verification reduces false activation risk. Safety and cyber controls must be integrated.
SPR-129	The [spacecraft] shall restrict the use of information inputs to spacecraft and designated ground stations as defined in the applicable ICDs.{SV-AC-1,SV-AC-2}{AC-20,SC-23,SI-10,SI-10(5),SI-10(6)}	Limiting inputs to approved spacecraft and ground stations reduces spoofing and injection risk. ICD-defined boundaries prevent rogue sources from influencing control systems. This constrains trust relationships. Controlled input surfaces reduce attack vectors.
SPR-130	The [spacecraft] shall discriminate between valid and invalid input into the software and rejects invalid input.{SV-SP-1,SV-IT-2}{SC-16(2),SI-3(8),SI-10,SI-10(3),SI-10(6)}	Input validation prevents buffer overflows, injection, and parser exploitation. Rejecting malformed or unexpected data reduces denial-of-service and corruption risks. Deterministic validation improves resilience. Robust input handling is fundamental to secure software.
SPR-131	The [spacecraft] shall identify and reject commands received out-of-sequence when the out-of-sequence commands can cause a hazard/failure or degrade the control of a hazard or mission.{SV-AC-2,SV-AV-4}{SC-16(2),SI-4(13),SI-4(25),SI-10,SI-10(6),SI-13}	Command sequencing enforces operational logic and safety interlocks. Out-of-sequence commands may bypass safeguards. Sequence enforcement prevents replay and control manipulation. This preserves control flow integrity.
SPR-140	The [spacecraft] shall properly handle spurious input and missing data.{SV-SP-1,SV-AV-6}{SI-10,SI-10(3),SI-10(6)}	Spurious or missing data may indicate attack or fault conditions. Robust handling prevents cascading failures. Defensive programming ensures safe defaults and fallback states. This reduces exploitability of abnormal input conditions.
SPR-141	The [spacecraft] shall perform prerequisite checks for the execution of hazardous commands.{SI-10,SI-10(6),SI-13}
SPR-142	The [spacecraft] shall only use or include critical commands for the purpose of providing emergency access where commanding authority is appropriately restricted.{SI-3(8),SI-10,SI-10(3)}
SPR-144	The [spacecraft] shall validate a functionally independent parameter prior to the issuance of any sequence that could remove an inhibit, or perform a hazardous action.{SV-AC-8,SV-MA-3}{SI-10(3),SI-10(6),SI-13}	Redundant validation mechanisms ensure hazardous transitions cannot occur through single-point compromise. Independent parameters strengthen control integrity. This reduces exploit paths for inhibit removal. Critical operations demand dual validation logic.
SPR-151	The [spacecraft] shall automatically [Selection (one or more):restarts the FSW/processor, performs side swap, audits failure; implements Program-defined security safeguards] when integrity violations are discovered.{SV-IT-2}{SI-7(8)}	Immediate system response prevents continued exploitation after detection. Restart, side swap, or safeguard activation restores known-good state. Automated actions reduce dwell time. Rapid containment is essential in communication-limited environments.
SPR-166	The [spacecraft] shall provide the capability to modify the set of audited events (e.g., cyber-relevant data).{SV-DCO-1}{AU-12(3),AU-14}	Flexibility allows adaptation to evolving threats. Adjustable audit scope ensures relevant telemetry is captured. This supports threat-driven monitoring strategies. Controlled modification preserves operational balance.
SPR-167	The [spacecraft] shall be configured to allocate audit record storage capacity in accordance with 1 week audit record storage requirements.{SV-DCO-1}{AU-4,AU-5,AU-5(1),AU-5(2)}	Defined storage capacity prevents premature log overwriting. Retention ensures forensic reconstruction capability. Adequate capacity supports delayed downlink scenarios. Storage planning enhances accountability.
SPR-168	The [spacecraft] shall downlink relevant audit log data to ground systems frequently enough to avoid any situation where audit storage capacity is exceeded.{SV-DCO-1}{AU-4(1)}	The frequency of offloading this data depends on the amount of data being audited/logged and will vary across missions/systems.
SPR-169	The [spacecraft] shall attribute cyberattacks and identify unauthorized use of the spacecraft by downlinking onboard cyber information to the mission ground station within [mission-appropriate timelines minutes].{SV-DCO-1}{AU-4(1),SI-4(5)}	Requirement is to support offboard attribution by enabling the fusion of spacecraft cyber data with ground-based cyber data. This would provide end-to-end accountability of commands, data, and other data that can be used to determine the origin of attack from the ground system. Data should be provided within time constraints relevant for the particular mission and its given operational mode. Analysis should be performed to identify the specific timeliness requirements for a mission, which may vary depending on mission mode, operational status, availability of communications resources, and other factors. The specific data required should be identified, as well.
SPR-170	The [spacecraft] shall alert in the event of the [organization]-defined audit/logging processing failures.{SV-DCO-1}{AU-5}	Audit failure may indicate tampering or resource exhaustion. Immediate alert prevents silent loss of visibility. Detection continuity is essential for defense. Monitoring integrity must be assured.
SPR-172	The [organization] shall integrate terrestrial system audit log analysis as part of the standard anomaly resolution process to correlate any anomalous behavior in the terrestrial systems that correspond to anomalous behavior in the spacecraft.{SV-DCO-1}{AU-6(1),IR-5(1)}	Correlation across ground and space segments improves attribution accuracy. End-to-end visibility detects pivoting attacks. Integration strengthens anomaly resolution. Enterprise/Whole mission fusion enhances threat awareness.
SPR-173	The [spacecraft] shall record time stamps for audit records that can be mapped to Coordinated Universal Time (UTC) or Greenwich Mean Time (GMT).{SV-DCO-1}{AU-8}	Standardized time enables cross-system correlation. Accurate timestamps are critical for forensic analysis. UTC/GMT alignment ensures interoperability. Consistent timekeeping supports coordinated response.
SPR-174	The [spacecraft] shall record time stamps for audit records that provide a granularity of one Z-count (1.5 sec).{SV-DCO-1}{AU-8}	Fine granularity improves event reconstruction accuracy. Short time resolution enables sequencing analysis. Precise timestamps strengthen evidentiary value. Temporal precision aids detection logic.
SPR-175	The [spacecraft] shall use internal system clocks to generate time stamps for audit records.{SV-DCO-1}{AU-8}	Using internal trusted clocks prevents manipulation via external time signals. Independent time generation strengthens integrity. This reduces risk of adversary-induced timeline distortion. Trusted time underpins reliable auditing.
SPR-181	The [spacecraft] shall employ advanced analytics capabilities within the IDS/IPS to address dynamic never-before-seen attacks using machine learning/adaptive technologies along with signature-based attacks. Models shall be trained and tuned using mission telemetry profiles to support predictive detection.{SV-DCO-1,SV-SP-1,SV-IT-2}{RA-3(4)}	Signature-based detection addresses known threats, while adaptive analytics detect novel or evolving behaviors. Spacecraft telemetry provides rich baseline data for predictive anomaly detection. Machine learning enhances early detection of zero-day or previously unseen tactics. Combining both approaches strengthens defense against advanced adversaries.
SPR-195	The [spacecraft] shall audit the communications characteristics (signals, frequencies, etc.) associated with denied communications.{SV-IT-1,SV-AV-1,SV-DCO-1}{SC-7(9)}	Recording denied communications supports detection of probing and reconnaissance. Signal analysis may reveal adversary tactics or spoofing attempts. Visibility strengthens attribution and tuning of defenses. Denied attempts provide intelligence value.
SPR-196	The [spacecraft] fault management solution shall utilize memory uncorrectable bit error detection information in a strategy to autonomously minimize the adverse effects of uncorrectable bit errors within the spacecraft.{SV-IT-4}{SI-16}	Radiation-induced errors may mimic malicious tampering. Integrating memory fault data into autonomous mitigation reduces impact. Rapid isolation prevents corrupted logic propagation. Cyber and radiation resilience must be coordinated.
SPR-197	The [spacecraft] Interrupt Service Routine (ISR) shall have the ability to simultaneously update check-bits for [organization]-defined memory addresses.{SV-IT-4}{SI-16}	Real-time integrity updates ensure memory protection during high-speed operations. ISR-based validation minimizes exposure windows. Immediate correction enhances reliability. Hardware-software coordination improves robustness.
SPR-198	The [spacecraft] shall integrate EDAC scheme with fault management and cyber-protection mechanisms to respond to the detection of uncorrectable multi-bit errors, other than time-delayed monitoring of EDAC telemetry by the mission operators on the ground.{SV-IT-4}{SI-16}	Uncorrectable errors may indicate attack or environmental damage. Automated response prevents reliance on delayed ground analysis. Integrated protection accelerates containment. Cybersecurity must leverage hardware integrity signals.
SPR-199	The [spacecraft] shall use Error Detection and Correcting (EDAC) memory.{SV-IT-4}{SI-16}	Error detection and correction protects against radiation-induced corruption. Single-bit correction prevents latent system faults. Memory integrity is foundational to secure execution. Hardware reliability directly supports cybersecurity.
SPR-200	The [spacecraft] shall utilize an EDAC scheme to routinely check for bit errors in the stored data on board the spacecraft, correct the single-bit errors, and identify the memory addresses of data with uncorrectable multi-bit errors of at least order two, if not higher order in some cases.{SV-IT-4}{SI-16}	Periodic checks detect accumulating degradation. Identifying affected addresses allows isolation of corrupted regions. Early detection prevents escalation into systemic failure. This supports predictive maintenance and anomaly detection.
SPR-201	The [spacecraft] shall monitor all inbound/outbound communications to detect unusual or unauthorized behavior and respond appropriately (disregard command, deny connection, etc.){SV-IT-1,SV-AC-2,SV-IT-2,SV-CF-1}{SI-4(4)}	Continuous traffic inspection detects unauthorized behavior. Both inbound and outbound flows may signal compromise. Real-time response reduces dwell time. Visibility across communication paths is essential in contested environments.
SPR-202	The [organization] shall define the security safeguards to be employed to protect the availability of system resources.{SV-AC-6}{SC-6,SI-17}	Explicit availability planning ensures defensive resources are provisioned. Clear safeguards prevent ad hoc reactions during incidents. Structured resilience planning supports mission assurance. Availability is often a primary operational objective.
SPR-203	The [spacecraft] shall have failure tolerance on sensors used by software to make mission-critical decisions.{SV-MA-3,SV-AV-7}{SI-13,SI-17}	Sensor compromise or failure must not directly lead to hazardous action. Redundancy and validation ensure trustworthy inputs. Independent verification reduces risk of manipulation. Critical decisions require reliable sensing.
SPR-204	The [spacecraft] cyber-safe mode software/configuration shall be stored onboard the spacecraft in memory with hardware-based controls and shall not be modifiable.{SV-AV-5,SV-AV-6,SV-AV-7}{SI-17}	Cyber-safe mode is using a fail-secure mentality where if there is a malfunction that the spacecraft goes into a fail-secure state where cyber protections like authentication and encryption are still employed (instead of bypassed) and the spacecraft can be restored by authorized commands. The cyber-safe mode should be stored in a high integrity location of the on-board SV so that it cannot be modified by attackers.
SPR-205	The [spacecraft] shall safely transition between all predefined, known states.{SV-AV-5,SV-AV-3,SV-AV-6}{SI-17}	Deterministic transitions prevent undefined or unstable states. Controlled state management limits exploitation windows. Safety logic must anticipate abnormal conditions. Predictable behavior enhances resilience.
SPR-206	The [spacecraft] software subsystems shall detect and recover/transition from detected memory errors to a known cyber-safe state.{SV-MA-3,SV-AV-7}{SI-17}	Memory corruption can degrade or hijack execution. Automated detection and transition to safe state prevents escalation. Recovery mechanisms reduce persistent compromise risk. Resilience requires automatic containment.
SPR-207	The [spacecraft] software subsystems shall initialize the spacecraft to a known safe state.{SV-MA-3,SV-AV-7}{SI-17}	Startup is a vulnerable period for tampering. Initialization ensures clean baseline before operations begin. Safe defaults prevent unauthorized persistence. Boot integrity establishes trust.
SPR-208	The [spacecraft] software subsystems shall operate securely in off-nominal power conditions, including loss of power and spurious power transients.{SV-MA-3,SV-AV-7}{SI-17}	Power instability may disrupt security controls. Robust design prevents exploit via induced power anomalies. Controlled behavior during transients preserves integrity. Cyber resilience must consider physical fault conditions.
SPR-209	The [spacecraft] software subsystems shall perform an orderly, controlled system shutdown to a known cyber-safe state upon receipt of a termination command or condition.{SV-MA-3,SV-AV-7}{SI-17}	Graceful shutdown prevents data corruption and incomplete processes. Controlled transitions reduce recovery complexity. Secure shutdown blocks adversary exploitation during failure states. Predictable termination supports resilience.
SPR-210	The [spacecraft] software subsystems shall recover to a known cyber-safe state when an anomaly is detected.{SV-MA-3,SV-AV-7}{SI-17}	Anomaly-triggered containment reduces attacker dwell time. Safe fallback states preserve mission viability. Autonomous response is essential given communication latency. Rapid isolation prevents lateral spread.
SPR-211	The [spacecraft] software subsystems shall safely transition between all predefined, known states.{SV-MA-3,SV-AV-7}{SI-17}	Safe and deterministic state transitions prevent undefined behavior that could be exploited during abnormal or adversarial conditions. Many cyber and fault-based attacks attempt to force systems into unexpected transitional states where validation checks may be bypassed. By ensuring transitions only occur along predefined, verified paths, the spacecraft reduces opportunities for logic corruption or hazardous command execution. Controlled state management strengthens both safety assurance and cybersecurity resilience.
SPR-236	The [organization] shall implement a verifiable flaw remediation process into the developmental and operational configuration management process.{SV-SP-1,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-2,CA-5,SA-3,SA-3(1),SA-11,SI-3,SI-3(10)}	The verifiable process should also include a cross reference to mission objectives and impact statements. Understanding the flaws discovered and how they correlate to mission objectives will aid in prioritization.
SPR-245	The [organization] shall define processes and procedures to be followed when integrity verification tools detect unauthorized changes to software, firmware, and information.{SV-IT-2}{CM-3,CM-3(1),CM-3(5),CM-5(6),CM-6,CP-2,IR-6,IR-6(2),PM-30,SC-16(1),SC-51,SI-3,SI-4(7),SI-4(24),SI-7,SI-7(7),SI-7(10)}	Predefined response procedures reduce reaction time. Clear escalation paths improve containment. Consistent handling prevents confusion during incidents. Preparedness strengthens resilience.
SPR-254	The [organization] shall employ dynamic analysis (e.g.using simulation, penetration testing, fuzzing, etc.) to identify software/firmware weaknesses and vulnerabilities in developed and incorporated code (open source, commercial, or third-party developed code).{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-8,CM-10(1),RA-3(1),SA-11(5),SA-11(8),SA-11(9),SI-3,SI-7(10)}	Dynamic testing uncovers runtime vulnerabilities not visible through static review. Techniques such as fuzzing and penetration testing simulate realistic adversarial behavior. Runtime validation improves detection of memory corruption, logic flaws, and unsafe state transitions. This reduces latent vulnerabilities prior to deployment.
SPR-255	The [organization] shall employ independent third-party analysis and penetration testing of all software (COTS, FOSS, Custom) associated with the system, system components, or system services.{SV-SP-1,SV-SP-3,SV-SP-6}{CA-2,CA-2(1),CA-8(1),CM-10(1),SA-9,SA-11(3),SA-12(11),SI-3,SI-3(10),SR-4(4),SR-6(1)}	Independent assessment reduces bias and uncovers blind spots in internal reviews. External testers provide objective validation of system resilience. Independent penetration testing strengthens confidence in defensive posture. Separation of duties enhances credibility and assurance.
SPR-259	The [organization] shall develop an incident response and forensics plan that covers the spacecrafts.{SV-MA-5}{CP-2,IR-1,IR-3,IR-3(2),IR-4(12),IR-4(13),IR-8,SA-15(10),SI-4(24)}	A structured response plan enables coordinated containment and recovery. Forensics planning ensures evidence preservation. Defined procedures reduce confusion during crisis. Incident readiness enhances resilience.
SPR-263	The [organization] shall provide training to its personnel on how to identify and respond to malicious code indicators to include but not limited to indicators of potentially malicious code in flight software, indicators from development machine’s anti-virus/anti-malware software of potential malicious code, and to recognize suspicious communications and anomalous behavior in [organization] information systems.{SV-SP-3,SV-SP-10}{AT-3(4),IR-6,IR-6(2),SI-4(24)}	Personnel must recognize signs of compromised flight or development systems. Early detection prevents propagation into mission assets. Training strengthens defense across lifecycle stages. Awareness reduces supply chain exposure.
SPR-265	The [organization] shall report identified systems or system components containing software affected by recently announced cybersecurity-related software flaws (and potential vulnerabilities resulting from those flaws) to [organization] officials with cybersecurity responsibilities.{SV-SP-1,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-11}{IR-6,IR-6(2),SI-2,SI-3,SI-4(12),SR-4(4)}	Rapid reporting of vulnerable components enables proactive remediation. Awareness of newly disclosed flaws prevents exploitation. Coordination ensures mission-wide response. Visibility reduces systemic risk.
SPR-266	The [organization] shall determine the vulnerabilities/weaknesses that require remediation, and coordinate the timeline for that remediation, in accordance with the analysis of the vulnerability scan report, the mission assessment of risk, and mission needs.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-5,CM-3,RA-5,RA-7,SI-3,SI-3(10)}	Not all vulnerabilities carry equal mission impact. Risk-informed prioritization ensures critical flaws are addressed first. Coordinated timelines balance mission needs with security posture. Structured remediation strengthens governance.
SPR-267	The [organization] shall perform software component analysis (a.k.a.origin analysis) for developed or acquired software.{SV-SP-4,SV-SP-6}{CM-10,CM-10(1),RA-3(1),RA-5,SA-15(7),SI-3,SI-3(10),SR-4(4)}	Origin analysis identifies embedded third-party libraries and dependencies. Transparency reduces supply chain opacity. Knowing component lineage enables targeted vulnerability tracking. This mitigates inherited risk.
SPR-269	The [organization] shall ensure that the vulnerability scanning tools (e.g., static analysis and/or component analysis tools) used include the capability to readily update the list of potential information system vulnerabilities to be scanned.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,RA-5(1),RA-5(3),SI-3}	Threat landscapes evolve rapidly. Regular tool updates ensure detection coverage remains current. Outdated signatures create blind spots. Continuous improvement sustains effectiveness.
SPR-270	The [organization] shall perform vulnerability analysis and risk assessment of all systems and software. The analysis shall include results from hardware‑in‑the‑loop vulnerability scanning of flight software, firmware, and link‑segment interfaces.{SV-SP-1,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,RA-5(3),SA-15(7),SI-3}	Integrated hardware-in-the-loop testing identifies operationally relevant weaknesses. Combined software, firmware, and interface scanning provides holistic coverage. Risk assessment ensures mitigation aligns with mission priorities. End-to-end analysis strengthens assurance.
SPR-271	The [organization] shall ensure that vulnerability scanning tools and techniques are employed that facilitate interoperability among tools and automate parts of the vulnerability management process by using standards for: (1) Enumerating platforms, custom software flaws, and improper configurations; (2) Formatting checklists and test procedures; and (3) Measuring vulnerability impact. Scanning shall cover flight software, firmware, and link‑segment interfaces in hardware‑in‑the‑loop environments.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,RA-5(3),SI-3}	Component/Origin scanning looks for open-source libraries/software that may be included into the baseline and looks for known vulnerabilities and open-source license violations.
SPR-274	The [organization] shall analyze vulnerability/weakness scan reports and results from security control assessments.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,SI-3}	Scan results require expert interpretation to avoid false positives or overlooked risks. Structured analysis ensures meaningful remediation. Correlating findings with mission context refines prioritization. Review strengthens governance.
SPR-277	In coordination with [organization], the [organization] shall prioritize and remediate flaws identified during security testing/evaluation.{SV-SP-1,SV-SP-3}{CA-2,CA-5,SA-11,SI-3,SI-3(10)}	Timely remediation reduces exploitation window. Coordination ensures mission continuity during patching. Documented prioritization demonstrates due diligence. Structured response enhances accountability.
SPR-291	The [organization] shall use the threat and vulnerability analyses of the as-built system, system components, or system services to inform and direct subsequent testing/evaluation of the as-built system, component, or service.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-3(3),SA-11(2),SA-15(8),SI-3}	Security analysis should guide test design. Threat-informed evaluation improves relevance. Feedback loops strengthen defensive posture. Analytical alignment enhances coverage.
SPR-295	The [organization] shall perform and document threat and vulnerability analyses of the as-built system, system components, or system services.{SV-SP-1,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-11(2),SI-3}	Formal records preserve findings and mitigation strategies. Documentation supports lifecycle traceability. Transparent records enhance oversight. Governance requires evidence.
SPR-300	The [organization] shall maintain the integrity of the mapping between the master build data (hardware drawings and software/firmware code) describing the current version of hardware, software, and firmware and the on-site master copy of the data for the current version.{SV-SP-4,SV-SP-9}{CM-6,SA-8(21),SA-8(30),SA-10,SA-10(3),SA-10(4),SA-10(5),SI-7(10),SR-4(4)}	Build data linkage ensures reproducibility and traceability. Tampering detection depends on accurate mapping. Integrity of master copies prevents unauthorized modification. Configuration discipline supports resilience.
SPR-308	The [organization] shall protect against supply chain threats to the system, system components, or system services by employing security safeguards as defined by NIST SP 800-161 Rev.1.{SV-SP-3,SV-SP-4,SV-AV-7,SV-SP-11}{PM-30,RA-3(1),SA-8(9),SA-8(11),SA-12,SI-3,SR-1}	The chosen supply chain safeguards should demonstrably support a comprehensive, defense-in-breadth information security strategy. Safeguards should include protections for both hardware and software. Program should define their critical components (HW & SW) and identify the supply chain protections, approach/posture/process.
SPR-309	The [organization] shall identify the key system components or capabilities that require isolation through physical or logical means.{SV-AC-6}{AC-3,SC-3,SC-7(13),SC-28(3),SC-32,SC-32(1)}	Fault management and security management capabilities would be classified as mission critical and likely need separated. Additionally, capabilities like TT&C, C&DH, GNC might need separated as well.
SPR-323	The [organization] prohibits the use of binary or machine-executable code from sources with limited or no warranty and without the provision of source code.{CM-7(8),CM-7(8),CM-10(1),SA-8(9),SA-8(11),SA-10(2),SI-3,SR-4(4)}
SPR-329	The [organization] shall perform manual code review of all produced code looking for quality, maintainability, and security flaws.{SV-SP-1}{SA-11(4),SI-3,SI-3(10),SR-4(4)}	Automated tools may miss contextual or logic-based flaws. Manual review improves detection of subtle security weaknesses. Human analysis enhances code quality and maintainability. Combined approaches strengthen overall assurance.
SPR-331	The [organization] shall test software and firmware updates related to flaw remediation for effectiveness and potential side effects on mission systems in a separate test environment before installation.{SV-SP-1,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CM-3,CM-3(1),CM-3(2),CM-4(1),CM-4(2),CM-10(1),SA-8(31),SA-11(9),SI-2,SI-3,SI-3(10),SI-7(10),SI-7(12),SR-5(2)}	This requirement is focused on software and firmware flaws. If hardware flaw remediation is required, refine the requirement to make this clear.
SPR-337	The [organization] shall ensure that the list of potential system vulnerabilities scanned is updated [prior to a new scan] {SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5(2),SI-3}	Outdated vulnerability signatures reduce detection capability. Updating scan definitions ensures coverage against emerging threats. Proactive updates prevent blind spots. Continuous refresh strengthens scanning effectiveness.
SPR-357	The [organization] defines the security safeguards to be employed to protect the availability of system resources.{CP-2(2),SC-6,SI-13,SI-17}
SPR-386	The [organization] shall implement automated mechanisms to assist in the execution and implementation of the Continuous Monitoring Program (CMP).{SV-DCO-1}{CA-7(6)}	Automation ensures continuous monitoring activities are consistent, repeatable, and not dependent on manual effort. Space systems generate large volumes of telemetry that require automated analysis to detect trends and anomalies. Automation reduces human error and accelerates response timelines. This strengthens adaptive security posture over the mission lifecycle.
SPR-415	The [organization] shall engage relevant stakeholders to discuss performance impacts/tradeoffs for implementing the desired monitoring approach, document any deviations from initial desired approach, and ensure the Authorizing Official (AO) signs off on the risk posed by the exclusion of the functionality in question.{SV-DCO-1,SV-AV-3,SV-AV-2}{AU-2}	Aerospace work published in TOR-2019-02178 "Telemetry Security" provides examples of telemetry values that may be useful to monitor for indications of malicious onboard activity (not a comprehensive list): Vehicle Command Counter (VCC) Rejected Command Counter Command Receiver On/Off Mode Command Receivers Received Signal Strength Command Receiver Lock Modes Telemetry Downlink Modes Cryptographic Modes Received Commands System Clock GPS Ephemeris Watchdog Timer (WDT)
SPR-416	The [organization] shall identify and document the on-board events and values that will be monitored for indicators of unexpected or malicious activity.{SV-DCO-1,SV-IT-1}{AU-2}	Aerospace work published in TOR-2019-02178 "Telemetry Security" provides examples of telemetry values that may be useful to monitor for indications of malicious onboard activity (not a comprehensive list): Vehicle Command Counter (VCC) Rejected Command Counter Command Receiver On/Off Mode Command Receivers Received Signal Strength Command Receiver Lock Modes Telemetry Downlink Modes Cryptographic Modes Received Commands System Clock GPS Ephemeris Watchdog Timer (WDT)
SPR-434	The [organization] shall determine criteria for unusual or unauthorized activities or conditions for all communications to/from the spacecraft.{SV-DCO-1,SV-IT-1}{SI-4(4)}	Clear anomaly criteria enable consistent detection. Defined thresholds prevent subjective interpretation. Structured definitions strengthen monitoring logic. Proactive detection improves response speed.
SPR-437	The [organization] shall enable integrity verification of software and firmware components.{SV-IT-2}{CM-3(5),CM-5(6),CM-10(1),SA-8(9),SA-8(11),SA-8(21),SA-10(1),SI-3,SI-4(24),SI-7,SI-7(10),SI-7(12),SR-4(4)}	* The integrity verification mechanisms may include: Stipulating and monitoring logical delivery of products and services, requiring downloading from approved, verification-enhanced sites; Encrypting elements (software, software patches, etc.) and supply chain process data in transit (motion) and at rest throughout delivery; Requiring suppliers to provide their elements “secure by default”, so that additional configuration is required to make the element insecure; Implementing software designs using programming languages and tools that reduce the likelihood of weaknesses; Implementing cryptographic hash verification; and Establishing performance and sub-element baseline for the system and system elements to help detect unauthorized tampering/modification during repairs/refurbishing. Stipulating and monitoring logical delivery of products and services, requiring downloading from approved, verification-enhanced sites; Encrypting elements (software, software patches, etc.) and supply chain process data in transit (motion) and at rest throughout delivery; Requiring suppliers to provide their elements “secure by default”, so that additional configuration is required to make the element insecure; Implementing software designs using programming languages and tools that reduce the likelihood of weaknesses; Implementing cryptographic hash verification; and Establishing performance and sub-element baseline for the system and system elements to help detect unauthorized tampering/modification during repairs/refurbishing.
SPR-439	For ASICs that are designed, developed, manufactured, packaged, or tested by a supplier that is not DMEA accredited, the ASIC development shall undergo a threat/vulnerability risk assessment. Based on the results of the risk assessment, the [organization] may need to implement protective measures or other processes to ensure the integrity of the ASIC.{SV-SP-5}{SA-8(9),SA-8(11),SA-8(21),SA-12,SA-12(1),SR-1,SR-4(4),SR-5}	DOD-I-5200.44 requires the following: 4.c.2 “Control the quality, configuration, and security of software, firmware, hardware, and systems throughout their lifecycles... Employ protections that manage risk in the supply chain… (e.g., integrated circuits, field-programmable gate arrays (FPGA), printed circuit boards) when they are identifiable (to the supplier) as having a DOD end-use. “ 4.e “In applicable systems, integrated circuit-related products and services shall be procured from a Trusted supplier accredited by the Defense Microelectronics Activity (DMEA) when they are custom-designed, custommanufactured, or tailored for a specific DOD military end use (generally referred to as application-specific integrated circuits (ASIC)). “ 1.g “In coordination with the DOD CIO, the Director, Defense Intelligence Agency (DIA), and the Heads of the DOD Components, develop a strategy for managing risk in the supply chain for integrated circuit-related products and services (e.g., FPGAs, printed circuit boards) that are identifiable to the supplier as specifically created or modified for DOD (e.g., military temperature range, radiation hardened).
SPR-446	The [organization] shall enable integrity verification of hardware components.{SV-SP-5,SV-SP-4}{SA-10(3),SA-8(21),SA-10(3),SC-51}	* The integrity verification mechanisms may include: Stipulating and monitoring logical delivery of products and services, requiring downloading from approved, verification-enhanced sites; Encrypting elements (software, software patches, etc.) and supply chain process data in transit (motion) and at rest throughout delivery; Requiring suppliers to provide their elements “secure by default”, so that additional configuration is required to make the element insecure; Implementing software designs using programming languages and tools that reduce the likelihood of weaknesses; Implementing cryptographic hash verification; and Establishing performance and sub-element baseline for the system and system elements to help detect unauthorized tampering/modification during repairs/refurbishing. Stipulating and monitoring logical delivery of products and services, requiring downloading from approved, verification-enhanced sites; Encrypting elements (software, software patches, etc.) and supply chain process data in transit (motion) and at rest throughout delivery; Requiring suppliers to provide their elements “secure by default”, so that additional configuration is required to make the element insecure; Implementing software designs using programming languages and tools that reduce the likelihood of weaknesses; Implementing cryptographic hash verification; and Establishing performance and sub-element baseline for the system and system elements to help detect unauthorized tampering/modification during repairs/refurbishing.
SPR-452	The [spacecraft] shall deny commands, data requests, and connections from revoked identities and shall generate an audit record for each denial.{SV-AC-4,SV-DCO-1}{AC-3,AC-3(8),AU-2,AU-12}	Explicit denial and logging strengthens accountability. Automated enforcement reduces reliance on manual monitoring. Recorded denials support forensic investigation. Policy adherence strengthens defense.
SPR-453	The [spacecraft] shall restrict any override of access control mechanisms to [Program-defined emergency conditions] and shall generate an auditable event for each invocation that includes the time, origin, justification code, affected functions, and exit status.{SV-AC-4}{AC-3,AC-3(10),AU-2,AU-3}	Overrides introduce risk and must be tightly constrained. Auditable invocation ensures accountability. Time-limited emergency use reduces misuse potential. Structured control preserves integrity.
SPR-454	The [spacecraft] shall tag telemetry and logs produced during override and shall automatically restore standard enforcement when exit conditions are met or after [Program-defined timeout].{SV-AC-4,SV-DCO-1}{AC-3(10),AU-3,AU-12}	Override transparency ensures operators are aware of elevated state. Automatic restoration prevents lingering weakened posture. Structured tagging supports audit and review. Governance reduces accidental persistence.
SPR-460	The [spacecraft] shall record transitive forwarding decisions and rejections in cyber relevant audit data for downlink.{SV-DCO-1}{CA-3(7),AU-3,AU-12}	Audit records of forwarding and rejection decisions enable forensic reconstruction. Visibility into routing logic prevents covert channel abuse. Logged rejections demonstrate enforcement of policy. Downlink visibility strengthens ground oversight.
SPR-461	The [spacecraft] shall fail over mission critical processing to a redundant onboard compute element while maintaining authentication, authorization, and cryptographic protections.{SV-MA-5}{CP-2(6),CP-10}	Redundant compute without preserved security controls introduces new risk. Failover must maintain authentication and cryptographic state. Secure redundancy prevents availability from undermining integrity. Resilience must not weaken protection.
SPR-468	The [spacecraft] shall detect and report the connection of any unauthorized or unknown component to onboard interfaces.{SV-SP-5,SV-SP-4}{PE-20,CM-8(3),SI-4}	Hardware implants pose existential mission risk. Detection of unknown components prevents covert insertion. Automated alerting reduces dwell time. Inventory integrity supports physical security.
SPR-469	The [spacecraft] shall log component activation, deactivation, replacement, and firmware updates with timestamps that map to UTC.{SV-SP-9,SV-DCO-1}{AU-3,AU-8}	Lifecycle logging ensures traceability. UTC mapping supports synchronized forensic analysis. Transparent change history reduces repudiation. Logging strengthens accountability.
SPR-479	The [organization] shall define, baseline, and maintain the purposing of the space platform and link segment, including intended objectives, authorized capabilities, prohibited functions, and operational constraints, and shall use this baseline to bound requirements, updates, and on-orbit operations.{SV-AC-8,SV-MA-6}{PM-32,PL-8}	Defining authorized and prohibited functions prevents scope creep. Clear purposing bounds updates and operational use. Governance limits misuse potential. Structured baseline supports disciplined operations.
SPR-489	The [spacecraft] shall host privileged functions, including flight control and cryptographic key management, in physically separate processing domains that have no direct data bus connectivity to non privileged domains. {SV-AC-6,SV-AC-3}{SC-3,SC-32(1),SC-39}	Hardware-level separation prevents software bypass. Isolation protects flight control and key management. Physical boundaries strengthen trust. Segmentation enforces zero-trust architecture.
SPR-490	The [spacecraft] shall ensure cross domain exchanges occur only through [organization] defined, verified guards that enforce format, rate, and content checks.{SV-AC-6,SV-IT-2}{AC-4,SC-7,SC-32(1)}	Verified guards ensure controlled data exchange. Format and rate checks prevent covert channel exploitation. Enforced mediation supports mandatory control. Guarded exchange strengthens isolation.
SPR-495	The [spacecraft] shall detect impending failure of security components and initiate controlled failover to preserve confidentiality, integrity, and availability.{SV-MA-5,SV-DCO-1}{SI-4,SI-13,CP-10}	Early detection prevents cascading compromise. Controlled switchover maintains CIA properties. Structured alerting enhances situational awareness. Fault handling preserves assurance.
SPR-496	The [spacecraft] shall provide standby instances for [organization]-defined high-criticality security components and automatically switch to the standby upon failure detection, generating an immediate alert that includes the component identity, time, and fault reason.{SV-MA-5}{SI-13(4),CP-10,AU-5}	Automatic failover reduces human delay. Immediate alerts support oversight. Identity and fault logging strengthen accountability. Resilient architecture supports mission continuity.
SPR-514	The [spacecraft] shall emit a standardized accept/reject reason code for every telecommand, including mode/precondition results, parameter/range/sequence checks, and rate/temporal‑limit evaluations, and shall include the code in downlinked audit.{SV-DCO-1}{AU-3,AU-12}	Consistent reason codes enhance operator clarity and forensic traceability. Transparent rejection rationale reduces ambiguity. Downlinked codes support ground analysis. Deterministic feedback strengthens accountability.
SPR-517	The [organization] shall correlate station/operator session activity with pass schedules and spacecraft mode, alert on off‑schedule access and command families invalid for the current mode, and retain results as audit evidence.{SV-AC-4,SV-AC-1,SV-AV-4}{AC-17,AC-17(1),SI-4,AU-6}	Off-schedule or mode-inconsistent commands signal compromise. Correlation across dimensions strengthens anomaly detection. Audit retention supports post-event review. Context validation strengthens mission assurance.
SPR-519	The [spacecraft] shall cryptographically bind audit records to their origin using per‑record MACs/signatures or sequence‑linked hashes and include station/operator ID and selected RF/link indicators (e.g., SNR/BER, frame counters) when available; ground shall verify and log the results.{SV-IT-2,SV-AC-2,SV-DCO-1}{AU-3,AU-3(1),AU-9,AU-9(2),AU-10}	Per-record signatures prevent tampering or replay. Sequence linkage detects gaps. Including RF indicators enhances forensic value. Verified logging strengthens evidentiary integrity.
SPR-520	The [spacecraft] shall implement tiered audit retention with overwrite protection for [organization]-defined high‑value categories (e.g., crypto events, command outcomes, mode changes) and expose buffer health/occupancy and retention decisions in telemetry; priorities shall be tunable by phase/mode.{SV-DCO-1}{AU-4,AU-4(1),AU-11}	High-value events require overwrite protection. Tunable priorities align storage with mission phase. Telemetry exposure ensures transparency. Structured retention strengthens audit survivability.
SPR-521	The [spacecraft] shall prevent execution of [organization]-defined hazardous procedures when minimal auditing cannot be assured (e.g., verified buffer availability or local shadow log), while allowing essential safing actions; operator feedback shall distinguish “blocked due to no audit” from other rejects.{SV-AC-8,SV-DCO-1}{AC-3,AU-5,AU-5(2)}	Certain operations require audit traceability. Blocking when audit is unavailable prevents blind execution. Essential safing remains permitted. Conditional enforcement strengthens accountability.
SPR-522	The [organization] shall implement a canonical time base and identifiers (station ID, session ID, command ID/APID, image/bitstream IDs) across TT&C front ends, consoles, and on‑board logs and shall de‑duplicate and gap‑detect during aggregation with rules for the source of truth for command history.{SV-IT-1,SV-AC-2,SV-DCO-1}{AU-6,AU-6(4),AU-8,IA-4}	Unified identifiers prevent ambiguity in command history. Gap detection identifies dropped or spoofed entries. Clear source-of-truth logic prevents dispute. Time discipline strengthens forensic precision.
SPR-524	The [spacecraft] shall protect on‑board audit storage using ECC and periodic scrubbing, commit markers/journaling to survive partial writes, redundant partitions/devices where available, and prioritized retention for high‑value events.{SV-IT-4,SV-DCO-1}{AU-9,AU-9(3)}	ECC and journaling preserve log integrity under fault. Redundant partitions improve survivability. Prioritized retention protects high-value evidence. Durable logging strengthens mission accountability.
SPR-525	The [organization] shall enforce least privilege and separation of duties for audit data (distinct roles for viewing, exporting, administering logs), apply heightened protections to sensitive categories (e.g., crypto operations), and provide break‑glass pathways with strong auditing.{SV-AC-4}{AC-6,AU-9,AU-9(5)}	Separation of duties prevents misuse of logs. Break-glass pathways preserve emergency access with oversight. Heightened protections reduce tampering risk. Structured governance strengthens trust.
SPR-527	The [organization] shall ingest vendor advisories, SBOM deltas, and provenance changes for components/toolchains into the Continuous Monitoring Program and correlate exposure with the “as‑flown” configuration to prioritize mitigations.{SV-SP-6,SV-SP-4,SV-DCO-1}{CA-7,CA-7(6),CM-8}	Exposure must be evaluated against actual deployed versions. SBOM deltas enable precise mitigation prioritization. Continuous ingestion strengthens responsiveness. Configuration awareness improves risk management.
SPR-534	The [organization] shall deploy deception/canary artifacts in ground TT&C environments (e.g., decoy credentials, fake repositories, canary procedures that never propagate to flight) and integrate alerts into incident handling; mechanisms shall not induce hazardous commanding.{SV-AC-4,SV-MA-7}{IR-4,IR-4(12),SI-4}	Canary artifacts reveal credential misuse or lateral movement. Integration with incident handling accelerates response. Mechanisms must not impact flight safety. Controlled deception strengthens detection.
SPR-536	The [organization] shall capture on‑board and ground evidence, produce an “as‑run” timeline with decisions/assumptions, and feed findings into updated playbooks, training, twin/flatsat scenarios, risk registers, and baselines, verifying changes via rehearsal.{SV-DCO-1}{IR-4,CA-7}	Post-incident reconstruction improves institutional learning. Feeding findings into twins and training strengthens preparedness. Verification via rehearsal ensures improvement. Continuous feedback supports maturity.
SPR-542	The [spacecraft] shall reserve CPU/memory/link budget for essential TT&C (command authentication, attitude/power control loops, critical telemetry) and preempt/shape payload and nonessential traffic under stress.{SV-AV-1,SV-AC-8}{SC-5,SC-5(2),SC-6,CP-10}	Command authentication and attitude control may take precedence. Traffic shaping prevents payload starvation attacks. Priority enforcement preserves safe operations. Resource governance strengthens availability.
SPR-549	The [spacecraft] shall enforce memory‑protection hardening on flight processors (MPU/MMU isolation of partitions, W^X/no‑execute, stack canaries) and employ ECC with periodic scrubbing for critical memories; partition health and protection status shall be exposed in telemetry.{SV-IT-4,SV-SP-4}{SI-16,SC-39}	MPU/MMU isolation prevents partition compromise. W^X and stack canaries mitigate exploitation. ECC with scrubbing preserves memory integrity. Exposed health telemetry strengthens monitoring.