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;
Informational References
CENTRA - Chinese Research into Cyber Vulnerabilities of Satellite Bus Standards
The Program shall protect all fault management documents (i.e., FMEA/FMECA artifacts) from inadvertent and inappropriate disclosure.
Low-Level Requirements
Requirement
Rationale/Additional Guidance/Notes
This is not a cyber control for the spacecraft, but these controls would apply to ground system, contractor networks, etc. where design sensitive information would reside. NIST 800-171 is insufficient to properly protect this information from exposure, exfiltration, etc. Should require contractors to be CMMC 2.0 Level 3 certified (https://www.acq.osd.mil/cmmc/about-us.html).
The Program shall identify and properly classify mission sensitive design/operations information and access control shall be applied in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. {SV-CF-3,SV-AV-5} {SA-5}
Essential Elements of Information (EEI):
The Program shall protect documentation and Essential Elements of Information (EEI) as required, in accordance with the risk management strategy. {SV-CF-3,SV-AV-5} {SA-5}
Least privilege and need to know should be employed with the protection of all documentation. Documentation can contain sensitive information that can aid in vulnerability discovery, detection, and exploitation. For example, command dictionaries for ground and space systems should be handles with extreme care. Additionally, design documents for missions contain many key elements that if compromised could aid in an attacker successfully exploiting the system.
The Program shall distribute documentation to only personnel with defined roles and a need to know. {SV-CF-3,SV-AV-5} {SA-5}
See threat ID SV-CF-3 to help with protecting design specific information, in this case the FMEA/FMECA artifacts so that particular fault responses are not disclosed via documentation. {SV-AV-5}
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-10,CP-10(4),IR-4}
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.
The spacecraft shall provide the capability to enter the spacecraft into a configuration-controlled and integrity-protected state representing a known, operational cyber-safe state (e.g., cyber-safe mode). {SV-AV-5,SV-AV-6,SV-AV-7} {CP-12,SI-17,IR-4(3)}
The spacecraft shall enter a cyber-safe mode when conditions that threaten the spacecraft are detected with restrictions as defined based on the cyber-safe mode. {SV-AV-5,SV-AV-6,SV-AV-7} {CP-12,SI-17,IR-4(3)}
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.
The spacecraft's cyber-safe mode software/configuration should be stored onboard the spacecraft in memory with hardware-based controls and should not be modifiable. {SV-AV-5,SV-AV-6,SV-AV-7} {SI-17}
The spacecraft shall fail to a known secure state for all types of failures preserving information necessary to determine cause of failure and to return to operations with least disruption to mission operations. {SV-AV-5,SV-AV-6,SV-AV-7} {SC-24,SI-17}
The spacecraft shall generate error messages that provide information necessary for corrective actions without revealing information that could be exploited by adversaries. {SV-AV-5,SV-AV-6,SV-AV-7} {SI-11}
The spacecraft shall reveal error messages only to operations personnel monitoring the telemetry. {SV-AV-5,SV-AV-6,SV-AV-7} {SI-11}
Threat actors may gather information about the victim spacecraft's design that can be used for future campaigns or to help perpetuate other techniques. Information about the spacecraft can include software, firmware, encryption type, purpose, as well as various makes and models of subsystems.
Threat actors may gather information about any fault management that may be present on the victim spacecraft. This information can help threat actors construct specific attacks that may put the spacecraft into a fault condition and potentially a more vulnerable state depending on the fault response.
Threat actors may gather the launch date and time, location of the launch (country & specific site), organizations involved, launch vehicle, etc. This information can provide insight into protocols, regulations, and provide further targets for the threat actor, including specific vulnerabilities with the launch vehicle itself.
Threat actor may obtain information regarding the vehicle's flight termination system. Threat actors may use this information to perform later attacks and target the vehicle's termination system to have desired impact on mission.
Threat actors may gather information regarding safe-mode indicators on the victim spacecraft. Safe-mode is when all non-essential systems are shut down and only essential functions within the spacecraft are active. During this mode, several commands are available to be processed that are not normally processed. Further, many protections may be disabled at this time.
Threat actors may take advantage of the victim spacecraft being in safe mode and send malicious commands that may not otherwise be processed. Safe-mode is when all non-essential systems are shut down and only essential functions within the spacecraft are active. During this mode, several commands are available to be processed that are not normally processed. Further, many protections may be disabled at this time.
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 utilize techniques to create a single-event upset (SEU) which is a change of state caused by one single ionizing particle (ions, electrons, photons...) striking a sensitive node in a spacecraft(i.e., microprocessor, semiconductor memory, or power transistors). The state change is a result of the free charge created by ionization in or close to an important node of a logic element (e.g. memory "bit"). This can cause unstable conditions on the spacecraft depending on which component experiences the SEU. SEU is a known phenomenon for spacecraft due to high radiation in space, but threat actors may attempt to utilize items like microwaves to create a SEU.
Threat actors may take advantage of the victim spacecraft being in safe mode and send malicious commands that may not otherwise be processed. Safe-mode is when all non-essential systems are shut down and only essential functions within the spacecraft are active. During this mode, several commands are available to be processed that are not normally processed. Further, many protections may be disabled at this time.
Threat actors use flooding attacks to disrupt communications by injecting unexpected noise or messages into a transmission channel. There are several types of attacks that are consistent with this method of exploitation, and they can produce various outcomes. Although, the most prominent of the impacts are denial of service or data corruption. Several elements of the space vehicle may be targeted by jamming and flooding attacks, and depending on the time of the attack, it can have devastating results to the availability of the system.
Threat actors may utilize valid commanding as a mechanism for flooding as the processing of these valid commands could expend valuable resources like processing power and battery usage. Flooding the spacecraft bus, sub-systems or link layer with valid commands can create temporary denial of service conditions for the space vehicle while the spacecraft is consumed with processing these valid commands.
Threat actors inject noise/data/signals into the target channel so that legitimate messages cannot be correctly processed due to impacts to integrity or availability. Additionally, while this technique does not utilize system-relevant signals/commands/information, the target spacecraft may still consume valuable computing resources to process and discard the signal.
Threat actors may attempt to jam Global Navigation Satellite Systems (GNSS) signals (i.e. GPS, Galileo, etc.) to inhibit a spacecraft's position, navigation, and/or timing functions.
Threat actors may attempt to jam Global Navigation Satellite Systems (GNSS) signals (i.e. GPS, Galileo, etc.) to inhibit a spacecraft's position, navigation, and/or timing functions.
Threat actors may disable fault management within the victim spacecraft during the attack campaign. During the development process, many fault management mechanisms are added to the various parts of the spacecraft in order to protect it from a variety of bad/corrupted commands, invalid sensor data, and more. By disabling these mechanisms, threat actors may be able to have commands processed that would not normally be allowed.
Threat actors may take advantage of the victim spacecraft being in safe mode and send malicious commands that may not otherwise be processed. Safe-mode is when all non-essential systems are shut down and only essential functions within the spacecraft are active. During this mode, several commands are available to be processed that are not normally processed. Further, many protections (i.e. security features) may be disabled at this time which would ensure the threat actor achieves evasion.
This technique deals with the more physical aspects of CCD that may be utilized by threat actors. There are numerous ways a threat actor may utilize the physical operating environment to their advantage, including powering down and laying dormant within debris fields as well as launching EMI attacks during space-weather events.
Space weather and its associated hazards imposed on spacecraft are a well-studied field of their own. However, it is also important to note the potential for threat actors to take advantage of heightened periods of solar activity to conduct electromagnetic interference (EMI) operations as they may be falsely attributed to natural events.
Measures designed to mislead an adversary by manipulation, distortion, or falsification of evidence or information into a system to induce the adversary to react in a manner prejudicial to their interests. Threat actors may seek to deceive mission stakeholders (or even military decision makers) for a multitude of reasons. Telemetry values could be modified, attacks could be designed to intentionally mimic another threat actor's TTPs, and even allied ground infrastructure could be compromised and used as the source of communications to the spacecraft.
Measures designed to temporarily impair the use or access to a system for a period of time. Threat actors may seek to disrupt communications from the victim spacecraft to the ground controllers or other interested parties. By disrupting communications during critical times, there is the potential impact of data being lost or critical actions not being performed. This could cause the spacecraft's purpose to be put into jeopardy depending on what communications were lost during the disruption. This behavior is different than Denial as this attack can also attempt to modify the data and messages as they are passed as a way to disrupt communications.
Measures designed to temporarily eliminate the use, access, or operation of a system for a period of time, usually without physical damage to the affected system. Threat actors may seek to deny ground controllers and other interested parties access to the victim spacecraft. This would be done exhausting system resource, degrading subsystems, or blocking communications entirely. This behavior is different from Disruption as this seeks to deny communications entirely, rather than stop them for a length of time.
Measures designed to permanently impair (either partially or totally) the use of a system. Threat actors may target various subsystems or the hosted payload in such a way to rapidly increase it's degradation. This could potentially shorten the lifespan of the victim spacecraft.
This technique is a result of utilizing TTPs to create an impact and the applicable countermeasures are associated with the TTPs leveraged to achieve the impact
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 threat intelligence program helps an organization generate their own threat intelligence information and track trends to inform defensive priorities and mitigate risk. Leverage all-source intelligence services or commercial satellite imagery to identify and track adversary infrastructure development/acquisition. Countermeasures for this attack fall outside the scope of the mission in the majority of cases.
Use threat modeling, attack surface analysis, and vulnerability analysis to inform the current development process using analysis from similar systems, components, or services where applicable. Reduce attack surface where possible based on threats.
Conduct a criticality analysis to identify mission critical functions, critical components, and data flows and reduce the vulnerability of such functions and components through secure system design. Focus supply chain protection on the most critical components/functions. Leverage other countermeasures like segmentation and least privilege to protect the critical components.
The credibility and effectiveness of many other types of defenses are enabled or enhanced by the ability to quickly detect, characterize, and attribute attacks against space systems. Space domain awareness (SDA) includes identifying and tracking space objects, predicting where objects will be in the future, monitoring the space environment and space weather, and characterizing the capabilities of space objects and how they are being used. Exquisite SDA—information that is more timely, precise, and comprehensive than what is publicly available—can help distinguish between accidental and intentional actions in space. SDA systems include terrestrial-based optical, infrared, and radar systems as well as space-based sensors, such as the U.S. military’s Geosynchronous Space Situational Awareness Program (GSSAP) inspector satellites. Many nations have SDA systems with various levels of capability, and an increasing number of private companies (and amateur space trackers) are developing their own space surveillance systems, making the space environment more transparent to all users.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Space-based RF mapping is the ability to monitor and analyze the RF environment that affects space systems both in space and on Earth. Similar to exquisite SDA, space-based RF mapping provides space operators with a more complete picture of the space environment, the ability to quickly distinguish between intentional and unintentional interference, and the ability to detect and geolocate electronic attacks. RF mapping can allow operators to better characterize jamming and spoofing attacks from Earth or from other satellites so that other defenses can be more effectively employed.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Satellite maneuver is an operational tactic that can be used by satellites fitted with chemical thrusters to avoid kinetic and some directed energy ASAT weapons. For unguided projectiles, a satellite can be commanded to move out of their trajectory to avoid impact. If the threat is a guided projectile, like most direct-ascent ASAT and co-orbital ASAT weapons, maneuver becomes more difficult and is only likely to be effective if the satellite can move beyond the view of the onboard sensors on the guided warhead.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Space systems can be operated and designed in ways that make them difficult to detect and track. Similar to platforms in other domains, stealthy satellites can use a smaller size, radar-absorbing coatings, radar-deflecting shapes, radar jamming and spoofing, unexpected or optimized maneuvers, and careful control of reflected radar, optical, and infrared energy to make themselves more difficult to detect and track. For example, academic research has shown that routine spacecraft maneuvers can be optimized to avoid detection by known sensors.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
A jammer or spoofer can be used to disrupt sensors on an incoming kinetic ASAT weapon so that it cannot steer itself effectively in the terminal phase of flight. When used in conjunction with maneuver, this could allow a satellite to effectively “dodge” a kinetic attack. Similar systems could also be used to deceive SDA sensors by altering the reflected radar signal to change the location, velocity, and number of satellites detected, much like digital radio frequency memory (DRFM) jammers used on many military aircraft today. A spacebased jammer can also be used to disrupt an adversary’s ability to communicate.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQGate with an ASAT weapon.
Deception can be used to conceal or mislead others on the “location, capability, operational status, mission type, and/or robustness” of a satellite. Public messaging, such as launch announcements, can limit information or actively spread disinformation about the capabilities of a satellite, and satellites can be operated in ways that conceal some of their capabilities. Another form of deception could be changing the capabilities or payloads on satellites while in orbit. Satellites with swappable payload modules could have on-orbit servicing vehicles that periodically move payloads from one satellite to another, further complicating the targeting calculus for an adversary because they may not be sure which type of payload is currently on which satellite. Satellites can also use tactical decoys to confuse the sensors on ASAT weapons and SDA systems. A satellite decoy can consist of an inflatable device designed to mimic the size and radar signature of a satellite, and multiple decoys can be stored on the satellite for deployment when needed. Electromagnetic decoys can also be used in space that mimic the RF signature of a satellite, similar to aircraft that use airborne decoys, such as the ADM-160 Miniature Air-launched Decoy (MALD).*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Satellites can be designed with antennas that “null” or minimize signals from a particular geographic region on the surface of the Earth or locations in space where jamming is detected. Nulling is useful when jamming is from a limited number of detectable locations, but one of the downsides is that it can also block transmissions from friendly users that fall within the nulled area. If a jammer is sufficiently close to friendly forces, the nulling antenna may not be able to block the jammer without also blocking legitimate users. Adaptive filtering, in contrast, is used to block specific frequency bands regardless of where these transmissions originate. Adaptive filtering is useful when jamming is consistently within a particular range of frequencies because these frequencies can be filtered out of the signal received on the satellite while transmissions can continue around them. However, a wideband jammer could interfere with a large enough portion of the spectrum being used that filtering out the jammed frequencies would degrade overall system performance. *
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
A space vehicle capable of docking with, manipulating, or maneuvering other satellites or pieces of debris can be used to thwart spacebased attacks or mitigate the effects after an attack has occurred. Such a system could be used to physically seize a threatening satellite that is being used to attack or endanger other satellites or to capture a satellite that has been disabled or hijacked for nefarious purposes. Such a system could also be used to collect and dispose of harmful orbital debris resulting from an attack. A key limitation of a physical seizure system is that each satellite would be time- and propellant-limited depending on the orbit in which it is stored. A system stored in GEO, for example, would not be well positioned to capture an object in LEO because of the amount of propellant required to maneuver into position. Physical seizure satellites may need to be stored on Earth and deployed once they are needed to a specific orbit to counter a specific threat.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Satellite components can be vulnerable to the effects of background radiation in the space environment and deliberate attacks from HPM and electromagnetic pulse weapons. The effects can include data corruption on memory chips, processor resets, and short circuits that permanently damage components.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Filters and shutters can be used on remote sensing satellites to protect sensors from laser dazzling and blinding. Filters can protect sensors by only allowing light of certain wavelengths to reach the sensors. Filters are not very effective against lasers operating at the same wavelengths of light the sensors are designed to detect because a filter that blocks these wavelengths would also block the sensor from its intended mission. A shutter acts by quickly blocking or diverting all light to a sensor once an anomaly is detected or a threshold is reached, which can limit damage but also temporarily interrupts the collection of data.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Laser systems can be used to dazzle or blind the optical or infrared sensors on an incoming ASAT weapon in the terminal phase of flight. This is similar to the laser infrared countermeasures used on aircraft to defeat heat-seeking missiles. Blinding an ASAT weapon’s guidance system and then maneuvering to a new position (if necessary) could allow a satellite to effectively “dodge” a kinetic attack. It could also be used to dazzle or blind the optical sensors on inspector satellites to prevent them from imaging a satellite that wants to keep its capabilities concealed or to frustrate adversary SDA efforts.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
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.
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.
Utilizing techniques to assure traffic flow security and confidentiality to mitigate or defeat traffic analysis attacks or reduce the value of any indicators or adversary inferences. This may be a subset of COMSEC protections, but the techniques would be applied where required to links that carry TT&C and/or data transmissions (to include on-board the spacecraft) where applicable given value and attacker capability. Techniques may include but are not limited to methods to pad or otherwise obfuscate traffic volumes/duration and/or periodicity, concealment of routing information and/or endpoints, or methods to frustrate statistical analysis.
Terminate the connection associated with a communications session at the end of the session or after an acceptable amount of inactivity which is established via the concept of operations.
This countermeasure is focused on the protection of terrestrial assets like ground networks and development environments/contractor networks, etc. Traditional detection technologies and capabilities would be applicable here. Utilizing resources from NIST CSF to properly secure these environments using identify, protect, detect, recover, and respond is likely warranted. Additionally, NISTIR 8401 may provide resources as well since it was developed to focus on ground-based security for space systems (https://nvlpubs.nist.gov/nistpubs/ir/2022/NIST.IR.8401.ipd.pdf). Furthermore, the MITRE ATT&CK framework provides IT focused TTPs and their mitigations https://attack.mitre.org/mitigations/enterprise/. Several recommended NIST 800-53 Rev5 controls are provided for reference when designing ground systems/networks.
Monitor defined telemetry points for malicious activities (i.e., jamming attempts, commanding attempts (e.g., command modes, counters, etc.)). This would include valid/processed commands as well as commands that were rejected. Telemetry monitoring should synchronize with ground-based Defensive Cyber Operations (i.e., SIEM/auditing) to create a full space system situation awareness from a cybersecurity perspective.
Attempt to cloak when in safe-mode and ensure that when the system enters safe-mode it does not disable critical security features. Ensure basic protections like encryption are still being used on the uplink/downlink to prevent eavesdropping.
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.
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.
Provide the capability to enter the spacecraft into a configuration-controlled and integrity-protected state representing a known, operational cyber-safe state (e.g., cyber-safe mode). Spacecraft should enter a cyber-safe mode when conditions that threaten the platform are detected. 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 software functions to pre-attack 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 equipment still available after a cyber-attack. The goal is for the spacecraft to resume full mission operations. If not possible, a reduced level of mission capability should be achieved. Cyber-safe mode software/configuration should be stored onboard the spacecraft in memory with hardware-based controls and should not be modifiable.
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.
Use Error Detection and Correcting (EDAC) memory and 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. The spacecraft should utilize the 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.
If available, use an authentication mechanism that allows GNSS receivers to verify the authenticity of the GNSS information and of the entity transmitting it, to ensure that it comes from a trusted source. Have fault-tolerant authoritative time sourcing for the spacecraft's clock. The spacecraft should synchronize the internal system clocks for each processor to the authoritative time source when the time difference is greater than the FSW-defined interval. If Spacewire is utilized, then the spacecraft should adhere to mission-defined time synchronization standard/protocol to synchronize time across a Spacewire network with an accuracy around 1 microsecond.
Utilize TRANSEC in order to prevent interception, disruption of reception, communications deception, and/or derivation of intelligence by analysis of transmission characteristics such as signal parameters or message externals. For example, jam-resistant waveforms can be utilized to improve the resistance of radio frequency signals to jamming and spoofing. Note: TRANSEC is that field of COMSEC which deals with the security of communication transmissions, rather than that of the information being communicated.