Software Digital Signature

Prevent the installation of Flight Software without verification that the component has been digitally signed using a certificate that is recognized and approved by the mission.

Sources

https://attack.mitre.org/mitigations/M1045/

https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-193.pdf

NIST Rev5 Controls

D3FEND Techniques

D3FEND Artifacts

ISO 27001

NASA Best Practice Guide

ESA Space Shield Mitigation

M2048

Related MITRE EMB3D Mitigations

Related CSF 2.0

Related BSI Security Measures

BM20

ID: CM0021

Tier: I

Ground CM

Created: 2022/10/19

Last Modified: 2025/04/15

Techniques Addressed by Countermeasure

ID		Name	Description
IA-0001		Compromise Supply Chain	Adversaries achieve first execution before the spacecraft ever flies by inserting malicious code, data, or configuration during manufacturing, integration, or delivery. Targets include software sources and dependencies, build systems and compilers, firmware/bitstreams for MCUs and FPGAs, configuration tables, test vectors, and off-the-shelf avionics. Inserted artifacts are designed to appear legitimate, propagate through normal processes, and activate under routine procedures or specific modes (e.g., safing, maintenance). Common insertion points align with where trust is assumed, vendor updates, mirrors and registries, CI/CD runners, programming stations, and “golden image” repositories. The result is pre-positioned access that blends with baseline behavior, often with delayed or conditional triggers and strong deniability.
	.02	Software Supply Chain	Here the manipulation targets software delivered to flight or ground systems: altering source before build, swapping signed binaries at distribution edges, subverting update metadata, or using stolen signing keys to issue malicious patches. Space-specific vectors include mission control applications, schedulers, gateway services, flight tables and configuration packages, and firmware loads during I&T or LEOP. Adversaries craft payloads that pass superficial validation, trigger under particular operating modes, or reintroduce known weaknesses through version rollback. “Data payloads” such as malformed tables, ephemerides, or calibration products can double as exploits when parsers are permissive. The objective is to ride the normal promotion pipeline so the implant arrives pre-trusted and executes as part of routine operations.
IA-0002		Compromise Software Defined Radio	Adversaries target SDR-based transceivers and payload radios because reconfigurable waveforms, FPGA bitstreams, and software flowgraphs create programmable footholds. Manipulation can occur in the radio’s development pipeline (toolchains, out-of-tree modules), at integration (loading of bitstreams, DSP coefficients, calibration tables), or in service via update channels that deliver new waveforms or patches. On-orbit SDRs often expose control planes (command sets for mode/load/select), data planes (baseband I/Q), and management/telemetry paths, any of which can embed covert behavior, alternate demod paths, or hidden subcarriers. A compromised SDR can establish clandestine command-and-control by activating non-public waveforms, piggybacking on idle fields, or toggling to time/ephemeris-triggered profiles that blend with nominal operations. On the ground, compromised SDR modems can be used to fabricate mission-compatible emissions or to decode protected downlinks for reconnaissance. Attackers leverage the SDR’s malleability so that malicious signaling, once seeded, presents as a legitimate but rarely exercised configuration.
IA-0004		Secondary/Backup Communication Channel	Adversaries pursue alternative paths to the spacecraft that differ from the primary TT&C in configuration, monitoring, or authentication. Examples include backup MOC/ground networks, contingency TT&C chains, maintenance or recovery consoles, low-rate emergency beacons, and secondary receivers or antennas on the vehicle. These channels exist to preserve commandability during outages, safing, or maintenance; they may use different vendors, legacy settings, or simplified procedures. Initial access typically pairs reconnaissance of failover rules with actions that steer operations onto the backup path, natural events, induced denial on the primary, or simple patience until scheduled tests and handovers occur. Once traffic flows over the alternate path, the attacker leverages its distinct procedures, dictionaries, or rate/size limits to introduce commands or data that would be harder to inject on the primary.
	.02	Receiver	Threat actors may target the spacecraft’s secondary (backup) RF receive path, often a differently sourced radio, alternate antenna/feed, or cross-strapped front end that is powered or enabled under specific modes. Threat actors map when the backup comes into play (safing, antenna obscuration, maintenance, link degradation) and what command dictionaries, framing, or authentication it expects. If the backup receiver has distinct waveforms, counters, or vendor defaults, the attacker can inject traffic that is accepted only when that path is active, limiting exposure during nominal ops. Forcing conditions that enable the backup, jamming the primary, exploiting geometry, or waiting for routine tests, creates the window for first execution. The result is a foothold gained through a rarely used RF path, exploiting differences in implementation and operational cadence between primary and standby receive chains.
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.
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-0004		Compromise Boot Memory	The attacker manipulates memory and configuration used in the earliest stages of boot so that their code runs before normal protections and integrity checks take hold. Targets include boot ROM vectors, first-stage/second-stage bootloaders, boot configuration words and strap pins, one-time-programmable (OTP) fuses, non-volatile images in flash/EEPROM, and scratch regions copied into RAM during cold start. Techniques range from replacing or patching boot images to flipping configuration bits that alter trust decisions (e.g., image selection, fallback order, watchdog behavior). Faults can be induced deliberately (timed power/clock/EM glitches) or via crafted update/write sequences that leave a partially programmed but executable state. Once resident, the modification can insert early hooks, disable or short-circuit checks, or select downgraded images; destructive variants corrupt the boot path to induce a persistent reset loop or safeing entry (a denial of service). Because boot logic initializes buses, memory maps, and handler tables, even small changes at this stage cascade, shaping how command handlers load, how keys and counters are initialized, and which peripherals are trusted for subsequent execution.
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.
	.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.
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.
	.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.
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.
EXF-0006		Modify Communications Configuration	The adversary alters radio/optical link configuration so the spacecraft emits mission data over paths the program does not monitor or control. Levers include retuning carriers, adding sidebands or subcarriers, changing modulation/coding profiles, remapping virtual channels/APIDs, editing beacon content, or redirecting routing tables in regenerative payloads. Data can be embedded steganographically (idle fields, padding, frame counters, pilot tones) or carried on a covert auxiliary downlink/crosslink pointed at attacker-owned apertures. Because these emissions conform to plausible waveforms and scheduler behavior, they appear as ordinary link activity while quietly conveying payload products, housekeeping, or file fragments to non-mission receivers.
	.01	Software Defined Radio	Programmable SDRs let an attacker introduce new waveforms or piggyback payloads into existing ones. By modifying DSP chains (filters, mixers, FEC, framing), the actor can: add a low-rate subcarrier under the main modulation, alter preamble/pilot sequences to encode bits, vary puncturing/interleaver patterns as a covert channel, or schedule brief “maintenance” bursts that actually carry exfiltrated data. Changes may be packaged as legitimate updates or configuration profiles so the SDR transmits toward attacker-visible geometry using standard equipment, while mission tooling interprets the emission as routine.
	.02	Transponder	On bent-pipe or regenerative transponders, configuration controls what is translated, amplified, and routed. An adversary can remap input–output paths, shift translation frequencies, adjust polarization or gain to favor non-mission receivers, or enable auxiliary ports so selected virtual channels or recorder playbacks are forwarded outside the planned ground segment. In regenerative systems, edited routing tables or QoS rules can mirror traffic to an attacker-controlled endpoint. The result is a sanctioned-looking carrier that quietly delivers mission data to unauthorized listeners.

Space Threats Addressed by Countermeasure

ID	Description
SV-IT-2	Unauthorized modification or corruption of data
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-IT-3	Compromise boot memory
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-AC-4	Masquerading as an authorized entity in order to gain access/Insider Threat
SV-SP-10	Compromise development environment source code (applicable to development environments not covered by threat SV-SP-1, SV-SP-3, and SV-SP-4).
SV-SP-4	General supply chain interruption or manipulation

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-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-17	The [spacecraft] shall protect the confidentiality and integrity of all information at rest using cryptography.{SV-CF-1,SV-CF-2,SV-AC-3}{AC-3,SA-8(19),SC-28,SC-28(1),SI-7(6)}	* The intent as written is for all transmitted traffic to be protected. This includes internal to internal communications and especially outside of the boundary.
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-50	The [spacecraft] shall implement cryptographic mechanisms to protect the confidentiality and integrity of information during transmission unless otherwise protected by approved physical safeguards.{SV-AC-7}{SC-8,SC-8(1),SC-8(4),SI-7(6)}	Unprotected transmission exposes telemetry, commands, and state information to interception or manipulation. Cryptographic protections ensure authenticity and confidentiality across all communication paths. Physical safeguards alone are insufficient in contested environments.
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-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-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-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-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-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-126	The [spacecraft] shall protect the confidentiality and integrity of the [all information] using cryptography while it is at rest.{SV-IT-2,SV-CF-2}{SC-28,SC-28(1),SI-7(6)}	* Information at rest refers to the state of information when it is located on storage devices as specific components of information systems. This is often referred to as data-at-rest encryption.
SPR-149	The [spacecraft] shall perform an integrity check of [Program-defined software, firmware, configuration parameters, and tables] at startup; at [Program-defined transitional states or security-relevant events] and shall verify integrity on receipt and prior to activation of any uploaded package.{SV-IT-2}{SI-7(1)}	Transitional states often introduce vulnerability windows. Integrity checks at these moments detect tampering before activation. Pre-activation validation prevents malicious update deployment. This reinforces chain-of-trust enforcement.
SPR-234	The [organization] shall develop and document program-specific identification and authentication policies for accessing the development environment and spacecraft. {SV-SP-10,SV-AC-4}{AC-3,AC-14,IA-1,SA-3,SA-3(1)}	Strong authentication prevents unauthorized development access. Development compromise can introduce malicious code. Documented policies ensure consistent enforcement. Identity governance supports supply chain integrity.
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-237	The [organization] shall establish robust procedures and technical methods to perform testing to include adversarial testing (i.e.abuse cases) of the platform hardware and software.{SV-SP-2,SV-SP-1}{CA-8,CP-4(5),RA-5,RA-5(1),RA-5(2),SA-3,SA-4(3),SA-11,SA-11(1),SA-11(2),SA-11(5),SA-11(7),SA-11(8),SA-15(7)}	Abuse-case testing reveals design weaknesses before deployment. Red-teaming strengthens defensive posture. Proactive validation reduces operational risk. Testing must simulate realistic threat scenarios.
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-251	The [organization] shall maintain evidence of the execution of the security assessment plan and the results of the security testing/evaluation.{SV-SP-1,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-2,CA-8,SA-11}	Documented evidence provides traceability and accountability for security testing activities. Without retained artifacts, organizations cannot demonstrate due diligence or validate corrective actions. Preserved results support audits, mission reviews, and lessons learned. This strengthens governance and compliance posture.
SPR-252	The [organization] shall create and implement a security assessment plan that includes: (1) The types of analyses, testing, evaluation, and reviews of all software and firmware components; (2) The degree of rigor to be applied to include abuse cases and/or penetration testing; and (3) The types of artifacts produced during those processes.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-2,CA-8,SA-11,SA-11(5)}	The security assessment plan should include evaluation of mission objectives in relation to the security of the mission. Assessments should not only be control based but also functional based to ensure mission is resilient against failures of controls.
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-256	The [organization] shall perform penetration testing/analysis: (1) On potential system elements before accepting the system; (2) As a realistic simulation of the active adversary’s known adversary tactics, techniques, procedures (TTPs), and tools; and (3) Throughout the lifecycle on physical and logical systems, elements, and processes.{SV-SP-3,SV-SP-4,SV-AV-7,SV-SP-11}{CA-8(1),SA-9,SA-11(5),SR-5(2)}	Penetration testing should be performed throughout the lifecycle on physical and logical systems, elements, and processes including: (1) Hardware, software, and firmware development processes; (2) Shipping/handling procedures; (3) Personnel and physical security programs; (4) Configuration management tools/measures to maintain provenance; and (5) Any other programs, processes, or procedures associated with the production/distribution of supply chain elements.
SPR-272	The [organization] shall perform static binary analysis of all firmware that is utilized on the spacecraft.{SV-SP-7,SV-SP-11}{RA-5,SA-10,SA-11,SI-7(10)}	Many commercial products/parts are utilized within the system and should be analyzed for security weaknesses. Blindly accepting the firmware is free of weakness is unacceptable for high assurance missions. The intent is to not blindly accept firmware from unknown sources and assume it is secure. This is meant to apply to firmware the vendors are not developing internally. In-house developed firmware should be going through the vendor's own testing program and have high assurance it is secure. When utilizing firmware from other sources, "expecting" does not meet this requirement. Each supplier needs to provide evidence to support that claim that their firmware they are getting is genuine and secure.
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-278	The [organization] shall correct flaws identified during security testing/evaluation.{SV-SP-1,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-11}	Flaws that impact the mission objectives should be prioritized.
SPR-279	The [organization] shall perform [Selection (one or more): unit; integration; system; regression] testing/evaluation at [Program-defined depth and coverage].{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-11}	The depth needs to include functional testing as well as negative/abuse testing.
SPR-280	The [organization] shall require the developer of the system, system component, or system service to deliver the system, component, or service with [Program-defined security configurations] implemented.{SV-SP-1,SV-SP-9}{SA-4(5)}	For the spacecraft FSW, the defined security configuration could include to ensure the software does not contain a pre-defined list of Common Weakness Enumerations (CWEs)and/or CAT I/II Application STIGs.
SPR-282	The [organization] shall use all-source intelligence analysis of suppliers and potential suppliers of the information system, system components, or system services to inform engineering, acquisition, and risk management decisions.{SV-SP-3,SV-SP-4,SV-AV-7,SV-SP-11}{PM-16,PM-30,RA-2,RA-3(1),RA-3(2),RA-7,SA-9,SA-12(8),SR-5(2)}	* The Program should also consider sub suppliers and potential sub suppliers. * All-source intelligence of suppliers that the organization may use includes: (1) Defense Intelligence Agency (DIA) Threat Assessment Center (TAC), the enterprise focal point for supplier threat assessments for the DOD acquisition community risks; (2) Other U.S. Government resources including: (a) Government Industry Data Exchange Program (GIDEP) – Database where government and industry can record issues with suppliers, including counterfeits; and (b) System for Award Management (SAM) – Database of companies that are barred from doing business with the US Government.
SPR-283	The [organization] shall request threat analysis of suppliers of critical components and manage access to and control of threat analysis products containing U.S.person information.{SV-SP-3,SV-SP-4,SV-SP-11}{PM-16,PM-30(1),RA-3(1),SA-9,SA-12,SR-1}	The intent of this requirement is to address supply chain concerns on hardware and software vendors. Not required for trusted suppliers accredited to the Defense Microelectronic Activity (DMEA). If the Program intends to use a supplier not accredited by DMEA, the government customer should be notified as soon as possible. If the Program has internal processes to vet suppliers, it may meet this requirement. All software used and its origins must be included in the SBOM and be subjected to internal and Government vulnerability scans.
SPR-293	The [organization] shall employ techniques to limit harm from potential adversaries identifying and targeting the [organization]s supply chain.{SV-SP-4,SV-SP-5,SV-SP-6}{CP-2,PM-30,SA-9,SA-12(5),SC-38,SR-3,SR-3(1),SR-3(2),SR-5(2)}	Adversaries often exploit supplier relationships. Protective measures reduce reconnaissance and manipulation. Supply chain resilience strengthens mission integrity. Proactive defense mitigates systemic exposure.
SPR-301	The [organization] shall develop a security plan for the spacecraft.{SV-MA-6}{PL-2,PL-7,PM-1,SA-8(29),SA-8(30)}	A comprehensive security plan aligns controls with mission objectives. Clear articulation ensures consistent implementation. Planning integrates security into operations. Formal documentation strengthens accountability.
SPR-302	The [organization] shall document the platform's security architecture, and how it is established within and is an integrated part of the overall [organization] mission security architecture.{SV-MA-6,SV-MA-4}{PL-7,SA-8(7),SA-8(13),SA-8(29),SA-8(30),SA-17}	Architecture documentation provides structural clarity. Integration into enterprise mission security ensures alignment. Clear documentation reduces misinterpretation. Transparency strengthens lifecycle governance.
SPR-305	The [organization] shall develop and implement anti-counterfeit policy and procedures designed to detect and prevent counterfeit components from entering the information system, including support tamper resistance and provide a level of protection against the introduction of malicious code or hardware.{SV-SP-3,SV-SP-4,SV-AV-7,SV-SP-11}{CM-3(8),CM-7(9),PM-30,SA-8(9),SA-8(11),SA-9,SA-10(3),SA-19,SC-51,SR-4(3),SR-4(4),SR-5(2),SR-11}	Counterfeit hardware may embed malicious implants. Formal policies reduce infiltration risk. Supplier verification strengthens trust. Hardware authenticity is foundational to cybersecurity.
SPR-306	The [organization] shall conduct a supplier review prior to entering into a contractual agreement with a sub [organization] to acquire systems, system components, or system services.{SV-SP-4,SV-SP-6}{PM-30,PM-30(1),RA-3(1),SA-8(9),SA-8(11),SA-9,SA-12(2),SR-5(2),SR-6}	Pre-contract review ensures vendor security posture. Due diligence reduces third-party risk exposure. Structured evaluation strengthens procurement governance. Supplier trust must be verified.
SPR-320	The [organization] shall develop and document program-specific configuration management policies and procedures for the hardware and software for the spacecraft. {SV-SP-9,SV-MA-6}{CM-1,CM-3,CM-5(6),SA-10,SA-10(3)}	Clear configuration governance prevents unauthorized modification. Policy-backed processes ensure consistency. Lifecycle control supports traceability. Managed change reduces mission risk.
SPR-321	The [organization] shall develop and document spacecraft integrity policies covering both hardware and software. {SV-SP-5,SV-IT-3}{CM-5(6),SA-10(3),SI-1,SI-7(12)}	Integrity policies define expectations for hardware and software protection. Formalized governance ensures consistent enforcement. Clear standards reduce ambiguity. Integrity underpins mission trustworthiness.
SPR-328	The [organization] shall ensure any update to on-board software, memory, or stored procedures has met high assurance standards before execution. {SV-SP-9,SV-SP-4}{AC-3(2),CM-3,SA-8(8),SA-8(31),SA-10(2),SR-4(4)}	On-orbit updates carry significant risk if not validated. High assurance standards prevent unauthorized or corrupted uploads from executing. Structured validation protects system integrity. Update governance reduces mission-ending configuration errors.
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-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-450	The [spacecraft] shall prevent flight software and payload applications from modifying access control labels or rules and shall validate label integrity at startup and during policy updates.{SV-AC-1,SV-IT-2}{AC-3(3),AC-3(11).AC-16,SI-7}	Label integrity ensures policy decisions remain trustworthy. Preventing modification protects data classification enforcement. Validation at startup prevents persistent compromise. Policy integrity underpins MAC assurance.
SPR-503	The [organization] shall validate authenticity and integrity of all flight-designated hardware, firmware, and software upon receipt using program-controlled trust anchors (approved vendor list, golden hash/cert manifest){SV-SP-4,SV-SP-5}{SR-4(3),SR-11,SI-7}	Receipt validation prevents counterfeit or tampered parts integration. Program-controlled trust anchors ensure consistency. Early detection reduces downstream risk. Intake verification strengthens SCRM posture.
SPR-504	The [organization] shall re-validate component identity (serial/lot), firmware measurements (cryptographic hashes), and certificate status immediately prior to installation, writing results to the SCRM/provenance ledger and blocking install on mismatch.{SV-SP-4,SV-SP-5}{SR-4(3),SR-11,SI-7}	Installation-time validation prevents stale or revoked components. Ledger recording strengthens traceability. Blocking on mismatch prevents compromise propagation. Continuous verification enhances assurance.
SPR-505	The [spacecraft] shall cryptographically verify boot images and configurations at power-on and after any update{SV-IT-3,SV-SP-9}{SR-4(3),SI-7,CM-14}	Secure boot prevents execution of unauthorized code. Post-update verification ensures integrity continuity. Root-of-trust enforcement protects mission-critical logic. Deterministic startup strengthens resilience.
SPR-516	The [organization] shall define,and the [spacecraft] shall enforce,guardrails for any unauthenticated discovery beacons (if used), limiting content to non‑sensitive signals that cannot enable timing/key inference, preventing state change via those paths, narrowing content in safe mode, and validating behavior in simulators/flatsats.{SV-CF-2,SV-IT-1}{AC-4,AC-14}	Discovery mechanisms can leak sensitive timing or state information. Guardrails restrict beacon content to non-sensitive data. Controlled discovery reduces inference risk.
SPR-528	The [organization] shall package each flight change (software, bitstreams, configuration tables) with a signed manifest, precondition checks (mode, power/thermal, link), explicit hold/commit points, and resumable procedures across AOS/LOS; the [spacecraft] shall enforce manifest checks prior to activation.{SV-SP-9,SV-IT-2}{CM-3,CM-3(2),SI-7,SA-10}	Manifest enforcement ensures integrity prior to activation. Precondition checks prevent unsafe changes. Resumable logic supports space contact constraints. Structured packaging strengthens update security.
SPR-531	The [spacecraft] shall enforce whitelisting for executable images and mission scripts/procedures by ID, hash, or signature, accept only artifacts produced by the mission build pipeline, and constrain interpreters/macros to sandboxed contexts with provenance checks on inputs.{SV-SP-9,SV-SP-4}{CM-7,CM-7(5),CM-7(8),SI-7}	Accepting only pipeline-produced artifacts prevents unauthorized code execution. Hash/signature validation ensures integrity. Sandbox constraints limit interpreter abuse. Provenance enforcement strengthens defense.
SPR-547	The [spacecraft] shall support chunked uploads of software/bitstreams/configuration with per‑chunk verification and commit markers, resumable across passes, with atomic activation and rollback if activation checks fail.{SV-SP-9,SV-IT-2}{SI-7,SI-7(15)}	Per-chunk verification prevents partial corruption. Atomic activation avoids inconsistent states. Rollback ensures safe recovery. Structured update logic strengthens resilience.
SPR-550	The [spacecraft] shall provide authenticated, auditable commands to inhibit or narrow subsystems/functions without risking loss of recovery paths, with explicit telemetry confirming resultant state; ground systems shall provide authenticated RF‑transmitter inhibits and rack‑level power controls with audit.{SV-AC-8,SV-MA-7}{PE-10,AC-6,AC-6(5),IA-2}	Controlled inhibit functions enable safe containment. Explicit telemetry confirms resultant state. Ground RF inhibits add physical-layer safety. Auditable containment strengthens operational control.