The Program shall ensure all hardware/backdoor commands available for use by the spacecraft are as expected.
Low-Level Requirements
Requirement
Rationale/Additional Guidance/Notes
The [organization] shall ensure that all viable commands are known to the mission and SV "owner.{SV-AC-8}{SI-10,SI-10(3)}
This is a concern for bus re-use. It is possible that the manufacturer left previously coded commands in their syntax rather than starting from a clean slate. This leaves potential backdoors and other functionality the mission does not know about.
The [organization] shall perform analysis of critical (backdoor) commands that could adversely affect mission success if used maliciously.{SV-AC-8}{SI-10,SI-10(3)}
Heritage and commercial products often have many residual operational (e.g., hardware commands) and test capabilities that are unidentified or unknown to the end user, perhaps because they were not expressly stated mission requirements. These would never be tested and their effects unknown, and hence, could be used maliciously. Test commands not needed for flight should be deleted from the flight database.
The [spacecraft] shall only use or include [organization]-defined critical commands for the purpose of providing emergency access where commanding authority is appropriately restricted.{SV-AC-8}{SI-10,SI-10(3)}
The intent is protect against misuse of critical commands. On potential scenario is where you could use accounts with different privileges, could require an additional passphrase or require entry into a different state or append an additional footer to a critical command. There is room for design flexibility here that can still satisfy this requirement.
Threat actors may modify the internal authentication process of the victim spacecraft to facilitate initial access, recurring execution, or prevent authorized entities from accessing the spacecraft. This can be done through the modification of the software binaries or memory manipulation techniques.
Threat actors can target the underlying hardware and/or firmware using various TTPs that will be dependent on the specific hardware/firmware. Typically, software tools (e.g., antivirus, antimalware, intrusion detection) can protect a system from threat actors attempting to take advantage of those vulnerabilities to inject malicious code. However, there exist security gaps that cannot be closed by the above-mentioned software tools since they are not stationed on software applications, drivers or the operating system but rather on the hardware itself. Hardware components, like memory modules and caches, can be exploited under specific circumstances thus enabling backdoor access to potential threat actors. In addition to hardware, the firmware itself which often is thought to be software in its own right also provides an attack surface for threat actors. Firmware is programming that's written to a hardware device's non-volatile memory where the content is saved when a hardware device is turned off or loses its external power source. Firmware is written directly onto a piece of hardware during manufacturing and it is used to run on the device and can be thought of as the software that enables hardware to run. In the spacecraft context, firmware and field programmable gate array (FPGA)/application-specific integrated circuit (ASIC) logic/code is considered equivalent to firmware.
Threat actors may utilize various hardware commands and perform malicious activities with them. Hardware commands typically differ from traditional command channels as they bypass many of the traditional protections and pathways and are more direct therefore they can be dangerous if not protected. Hardware commands are sometime a necessity to perform various actions such as configuring sensors, adjusting positions, and rotating internal motors. Threat actors may use these commands to perform malicious activities that can damage the victim spacecraft in some capacity.
Threat actors may perform specific techniques in order to bypass or disable the encryption mechanism onboard the victim spacecraft. By bypassing or disabling this particular mechanism, further tactics can be performed, such as Exfiltration, that may have not been possible with the internal encryption process in place.
Threat actors may find and target various hardware backdoors within the victim spacecraft in the hopes of maintaining their attack. Once in orbit, mitigating the risk of various hardware backdoors becomes increasingly difficult for ground controllers. By targeting these specific vulnerabilities, threat actors are more likely to remain persistent on the victim spacecraft and perpetuate further attacks.
Organizations should look to identify and properly classify mission sensitive design/operations information (e.g., fault management approach) and apply access control accordingly. Any location (ground system, contractor networks, etc.) storing design information needs to ensure design info is protected from exposure, exfiltration, etc. Space system sensitive information may be classified as Controlled Unclassified Information (CUI) or Company Proprietary. Space system sensitive information can typically include a wide range of candidate material: the functional and performance specifications, any ICDs (like radio frequency, ground-to-space, etc.), command and telemetry databases, scripts, simulation and rehearsal results/reports, descriptions of uplink protection including any disabling/bypass features, failure/anomaly resolution, and any other sensitive information related to architecture, software, and flight/ground /mission operations. This could all need protection at the appropriate level (e.g., unclassified, CUI, proprietary, classified, etc.) to mitigate levels of cyber intrusions that may be conducted against the project’s networks. Stand-alone systems and/or separate database encryption may be needed with controlled access and on-going Configuration Management to ensure changes in command procedures and critical database areas are tracked, controlled, and fully tested to avoid loss of science or the entire mission. Sensitive documentation should only be accessed by personnel with defined roles and a need to know. Well established access controls (roles, encryption at rest and transit, etc.) and data loss prevention (DLP) technology are key countermeasures. The DLP should be configured for the specific data types in question.
A component of cybersecurity to deny unauthorized persons information derived from telecommunications and to ensure the authenticity of such telecommunications. COMSEC includes cryptographic security, transmission security, emissions security, and physical security of COMSEC material. It is imperative to utilize secure communication protocols with strong cryptographic mechanisms to prevent unauthorized disclosure of, and detect changes to, information during transmission. Systems should also maintain the confidentiality and integrity of information during preparation for transmission and during reception. Spacecraft should not employ a mode of operations where cryptography on the TT&C link can be disabled (i.e., crypto-bypass mode). The cryptographic mechanisms should identify and reject wireless transmissions that are deliberate attempts to achieve imitative or manipulative communications deception based on signal parameters.
Leverage best practices for crypto key management as defined by organization like NIST or the National Security Agency. Leverage only approved cryptographic algorithms, cryptographic key generation algorithms or key distribution techniques, authentication techniques, or evaluation criteria. Encryption key handling should be performed outside of the onboard software and protected using cryptography. Encryption keys should be restricted so that they cannot be read via any telecommands.
Authenticate all communication sessions (crosslink and ground stations) for all commands before establishing remote connections using bidirectional authentication that is cryptographically based. Adding authentication on the spacecraft bus and communications on-board the spacecraft is also recommended.
Ensure fault management system cannot be used against the spacecraft. Examples include: safe mode with crypto bypass, orbit correction maneuvers, affecting integrity of telemetry to cause action from ground, or some sort of proximity operation to cause spacecraft to go into safe mode. Understanding the safing procedures and ensuring they do not put the spacecraft in a more vulnerable state is key to building a resilient spacecraft.
Ensure that all viable commands are known to the mission/spacecraft owner. Perform analysis of critical (backdoor/hardware) commands that could adversely affect mission success if used maliciously. Only use or include critical commands for the purpose of providing emergency access where commanding authority is appropriately restricted.