Detection of abnormal system calls originating from processes or binaries that are unexpected or not typically associated with certain system operations. This could indicate malicious activity such as the execution of a backdoor or malicious code, where the software is making system calls outside of its normal behavior.

STIX Pattern

[process:image_ref.name = 'unexpected_process' AND process:system_call = 'unexpected_system_call']

SPARTA TTPs

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.
IA-0001.02	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.
EX-0009.02	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.
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.
EX-0010.01	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.
EX-0010.02	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.
EX-0010.03	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.
EX-0012.03	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.
EX-0012.12	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.
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.
PER-0002.02	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.