CM0011 Vulnerability Scanning Vulnerability scanning systematically identifies known security weaknesses in commercial off-the-shelf (COTS) and open-source software (OSS) components, including vulnerable dependencies and outdated software versions, across spacecraft and ground system environments. Custom-developed code requires separate analysis approaches, such as static and dynamic code analysis, that fall outside the scope of this countermeasure; however, COTS, OSS, and third-party dependencies incorporated into custom-developed software remain within the scope of vulnerability scanning and SCA. Scanning programs should incorporate software composition analysis (SCA) to detect vulnerabilities introduced through third-party libraries and dependency chains, which represent a significant and frequently underestimated attack surface in modern space systems. Scanning tools and processes should conform to recognized interoperability standards that support enumeration of platforms, software flaws, and configuration weaknesses; standardized formatting of checklists and test procedures; and consistent measurement of vulnerability impact. Adherence to these standards enables automation of key vulnerability management workflow steps, facilitates tool interoperability across the mission ecosystem, and produces outputs that are comparable across programs and organizations.
Vulnerability scanning shall be performed against the approved as-built or deployed software baseline using methods that do not jeopardize mission operations. Active scanning of live spacecraft, safety-critical ground systems, or operational technology should occur only after the scanning method has been authorized and evaluated for operational impact. Where live scanning presents unacceptable risk, scanning should be performed against representative software images, firmware packages, or test environments that match the approved operational baseline.
CM0015 Software Source Control Binary or machine-executable code obtained from sources that provide no warranty and no access to the corresponding source code must not be incorporated into spacecraft or ground systems. This prohibition addresses a fundamental software assurance gap: without source code, missions cannot perform source-based static analysis or independently review and modify implementation details, and may have reduced ability to assess, repair, or extend the software. Code from sources with limited or no warranty and no source code provision may be difficult to independently analyze, repair, or extend and leaves the mission dependent on supplier assurances and remediation capabilities. This countermeasure applies throughout the software supply chain, including components integrated by subcontractors.
CM0019 Static Analysis Static source code analysis examines software without executing it, identifying security-relevant weaknesses in the codebase before they can be exploited at runtime. Static analysis must be performed across all available source code. The mission’s weakness prioritization (i.e., CM0016) process should guide tool configuration and finding triage without unnecessarily excluding other weakness classes supported by the tools. The static analysis program must employ no fewer than two distinct tools with complementary language and weakness-detection capabilities. The tools should be applied at defined points throughout the development and maintenance lifecycle to provide overlapping and complementary analysis coverage and reduce the likelihood that exploitable weaknesses persist into integration or deployment. Tool selection should account for language compatibility, weakness class coverage, and the ability to produce findings in formats that support triage and remediation tracking. Static analysis should be integrated into the software build pipeline as an automated, recurring activity rather than conducted as a periodic manual exercise, ensuring that new code contributions are analyzed continuously throughout development.
CM0021 Software Digital Signature Each software or firmware image subject to installation or update control shall be verified using an approved digital signature and an approved trust anchor before installation or activation. The trust anchor may be represented by a certificate or by a directly provisioned verification key, depending on the approved trust architecture. Successful verification establishes that the image was signed by an authorized signing identity and has not been modified since signing; it does not establish that the signed code is non-malicious, vulnerability-free, or operationally safe. Signature verification confirms the integrity and approved origin of the software but does not, by itself, prevent installation of an older validly signed version; update authorization and rollback protections must be enforced separately.
The verification mechanism must be implemented such that it cannot be bypassed through operational commands, configuration changes, or software updates, and must reject any component whose signature is absent or invalid, or whose signing certificate or trust anchor is not recognized and approved by the mission. Digital signature enforcement complements but is distinct from the boot-time chain of trust established through secure boot; it applies to software installation and update events throughout the operational lifecycle, not only at system startup.
CM0046 Long Duration Testing Long duration testing subjects spacecraft software, firmware, hardware, and relevant integrated ground interfaces, or representative simulation and emulation environments, to extended test execution of 30 days or more to expose security and reliability defects that may manifest only after prolonged operation or specific time-dependent conditions. Race conditions, memory or resource leaks, time-dependent state corruption, resource exhaustion, counter rollover, and time-triggered malicious behavior may not manifest during short-duration testing because their activation depends on accumulated runtime, rare timing interactions, or gradual changes in system state. Long duration testing increases the opportunity to expose these conditions before deployment and complements static analysis, formal analysis, stress testing, fault injection, and targeted rollover testing. Testing should use the highest-fidelity environment appropriate to the test objectives. Flight-representative hardware should be used where hardware timing, device behavior, or integration effects are material; validated simulation or emulation may be used for conditions that it represents with sufficient fidelity. Differences between the test environment and operational system must be documented and considered when interpreting results.
CM0047 Operating System Security The spacecraft operating system (OS) must be subjected to software assurance scrutiny commensurate with its mission criticality and security role. Prior assurance and flight-history evidence may be reused only after its applicability to the selected OS version, configuration, target hardware, operational use, and current mission security requirements has been evaluated. The OS must be analyzed for its attack surface, and all features, services, libraries, and interfaces not required for the mission's defined operational functions must be stripped, disabled, or removed before the OS is integrated into the flight software stack. This hardening requirement is particularly significant for some real-time operating systems (RTOS), which commonly include networking stacks, file systems, shell interfaces, diagnostic services, and other general-purpose capabilities that are unnecessary for spacecraft operations but expand the exploitable attack surface available to an adversary. Only an organization-approved OS product, version, build, and configuration baseline may be used in the delivered spacecraft system. The approved baseline must be enforced through reproducible build controls, configuration management, component inventories, and automated verification where supported.
CM0032 On-board Intrusion Detection & Prevention An on-board intrusion detection and prevention system (IDS/IPS) monitors mission-critical spacecraft components and systems, generates and stores audit records, and supports mission-approved responses to detected threats. Depending on the mission architecture, threat, and availability of ground support, responses may be autonomous, ground-directed, or a combination of both. The system should address both known attack patterns and previously unseen anomalous behavior through complementary signature-based and behavior- or anomaly-based detection methods. Machine learning or adaptive technologies may be used when their performance, resource consumption, and failure behavior have been validated for the mission environment. Detection and response coverage should address applicable adversary activities across the attack lifecycle, including initial access, execution, persistence, defense evasion, and exfiltration. The on-board IDS/IPS must be integrated with the spacecraft's traditional fault management system to provide a unified approach to anomaly response, ensuring that cyber-triggered responses are compatible with fault management logic and do not produce unintended effects or fratricide against the spacecraft's own systems; countermeasures that are incompatible with fault management are considered unsafe and must not be executed autonomously. The response hierarchy must prioritize vehicle safety and continued mission operations. Advanced containment or deception responses may be considered when they can be executed without unacceptable mission risk. The system should preserve evidence that supports post-event analysis, threat characterization, and potential attribution by authorized ground support.