AC-3(10) - Access Enforcement | Audited Override of Access Control Mechanisms

Employ an audited override of automated access control mechanisms under [Assignment: organization-defined conditions] by [Assignment: organization-defined roles].


Informational References

ISO 27001

ID: AC-3(10)
Enhancement of : AC-3

Countermeasures Covered by Control

ID Name Description D3FEND
CM0002 COMSEC 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. D3-ET D3-MH D3-MAN D3-MENCR D3-NTF D3-ITF D3-OTF D3-CH D3-DTP D3-NTA D3-CAA D3-DNSTA D3-IPCTA D3-NTCD D3-RTSD D3-PHDURA D3-PMAD D3-CSPP D3-MA D3-SMRA D3-SRA

Space Threats Tagged by Control

ID Description
SV-CF-2 Eavesdropping (RF and proximity)
SV-AC-1 Attempting access to an access-controlled system resulting in unauthorized access
SV-CF-1 Tapping of communications links (wireline, RF, network) resulting in loss of confidentiality; Traffic analysis to determine which entities are communicating with each other without being able to read the communicated information

Sample Requirements

Requirement
The spacecraft shall not employ a mode of operations where cryptography on the TT&C link can be disabled (i.e., crypto-bypass mode). {SV-AC-1,SV-CF-1,SV-CF-2} {AC-3(10)}

Related SPARTA Techniques and Sub-Techniques

ID Name Description
REC-0003 Gather Spacecraft Communications Information Threat actors may obtain information on the victim spacecraft's communication channels in order to determine specific commands, protocols, and types. Information gathered can include commanding patterns, antenna shape and location, beacon frequency and polarization, and various transponder information.
REC-0003.04 Valid Credentials Threat actors may seek out valid credentials which can be utilized to facilitate several tactics throughout an attack. Credentials may include, but are not limited to: system service accounts, user accounts, maintenance accounts, cryptographic keys and other authentication mechanisms.
REC-0005 Eavesdropping Threat actors may seek to capture network communications throughout the ground station and radio frequency (RF) communication used for uplink and downlink communications. RF communication frequencies vary between 30MHz and 60 GHz. Threat actors may capture RF communications using specialized hardware, such as software defined radio (SDR), handheld radio, or a computer with radio demodulator turned to the communication frequency. Network communications may be captured using packet capture software while the threat actor is on the target network.
REC-0005.01 Uplink Intercept Threat actors may capture the RF communications as it pertains to the uplink to the victim spacecraft. This information can contain commanding information that the threat actor can use to perform other attacks against the victim spacecraft.
REC-0005.02 Downlink Intercept Threat actors may capture the RF communications as it pertains to the downlink of the victim spacecraft. This information can contain important telemetry such as onboard status and mission data.
REC-0005.03 Proximity Operations Threat actors may capture signals and/or network communications as they travel on-board the vehicle (i.e., EMSEC/TEMPEST), via RF, or terrestrial networks. This information can be decoded to determine commanding and telemetry protocols, command times, and other information that could be used for future attacks.
REC-0005.04 Active Scanning (RF/Optical) Threat actors may interfere with the link by actively transmitting packets to activate the transmitter and induce a reply. The scan can be similar to a brute force attack, aiming to guess the used frequencies and protocols to obtain a reply.
IA-0003 Crosslink via Compromised Neighbor Threat actors may compromise a victim spacecraft via the crosslink communications of a neighboring spacecraft that has been compromised. spacecraft in close proximity are able to send commands back and forth. Threat actors may be able to leverage this access to compromise other spacecraft once they have access to another that is nearby.
IA-0005 Rendezvous & Proximity Operations Threat actors may perform a space rendezvous which is a set of orbital maneuvers during which a spacecraft arrives at the same orbit and approach to a very close distance (e.g. within visual contact or close proximity) to a target spacecraft.
IA-0005.01 Compromise Emanations Threat actors in close proximity may intercept and analyze electromagnetic radiation emanating from crypto equipment and/or the target spacecraft(i.e., main bus) to determine whether the emanations are information bearing. The data could be used to establish initial access.
IA-0005.02 Docked Vehicle / OSAM Threat actors may leverage docking vehicles to laterally move into a target spacecraft. If information is known on docking plans, a threat actor may target vehicles on the ground or in space to deploy malware to laterally move or execute malware on the target spacecraft via the docking interface.
IA-0005.03 Proximity Grappling Threat actors may posses the capability to grapple target spacecraft once it has established the appropriate space rendezvous. If from a proximity / rendezvous perspective a threat actor has the ability to connect via docking interface or expose testing (i.e., JTAG port) once it has grappled the target spacecraft, they could perform various attacks depending on the access enabled via the physical connection.
IA-0007 Compromise Ground System Threat actors may initially compromise the ground system in order to access the target spacecraft. Once compromised, the threat actor can perform a multitude of initial access techniques, including replay, compromising FSW deployment, compromising encryption keys, and compromising authentication schemes. Threat actors may also perform further reconnaissance within the system to enumerate mission networks and gather information related to ground station logical topology, missions ran out of said ground station, birds that are in-band of targeted ground stations, and other mission system capabilities.
IA-0007.02 Malicious Commanding via Valid GS Threat actors may compromise target owned ground systems components (e.g., front end processors, command and control software, etc.) that can be used for future campaigns or to perpetuate other techniques. These ground systems components have already been configured for communications to the victim spacecraft. By compromising this infrastructure, threat actors can stage, launch, and execute an operation. Threat actors may utilize these systems for various tasks, including Execution and Exfiltration.
IA-0008 Rogue External Entity Threat actors may gain access to a victim spacecraft through the use of a rogue external entity. With this technique, the threat actor does not need access to a legitimate ground station or communication site.
IA-0008.01 Rogue Ground Station Threat actors may gain access to a victim spacecraft through the use of a rogue ground system. With this technique, the threat actor does not need access to a legitimate ground station or communication site.
IA-0008.02 Rogue Spacecraft Threat actors may gain access to a target spacecraft using their own spacecraft that has the capability to maneuver within close proximity to a target spacecraft to carry out a variety of TTPs (i.e., eavesdropping, side-channel, etc.). Since many of the commercial and military assets in space are tracked, and that information is publicly available, attackers can identify the location of space assets to infer the best positioning for intersecting orbits. Proximity operations support avoidance of the larger attenuation that would otherwise affect the signal when propagating long distances, or environmental circumstances that may present interference.
IA-0010 Exploit Reduced Protections During Safe-Mode 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.
EX-0001 Replay Replay attacks involve threat actors recording previously recorded data streams and then resending them at a later time. This attack can be used to fingerprint systems, gain elevated privileges, or even cause a denial of service.
EX-0001.01 Command Packets Threat actors may interact with the victim spacecraft by replaying captured commands to the spacecraft. While not necessarily malicious in nature, replayed commands can be used to overload the target spacecraft and cause it's onboard systems to crash, perform a DoS attack, or monitor various responses by the spacecraft. If critical commands are captured and replayed, thruster fires, then the impact could impact the spacecraft's attitude control/orbit.
EX-0003 Modify Authentication Process 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.
EX-0006 Disable/Bypass Encryption 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.
EX-0011 Exploit Reduced Protections During Safe-Mode 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.
PER-0004 Replace Cryptographic Keys Threat actors may attempt to fully replace the cryptographic keys on the space vehicle which could lockout the mission operators and enable the threat actor's communication channel. Once the encryption key is changed on the space vehicle, the spacecraft is rendered inoperable from the operators perspective as they have lost commanding access. Threat actors may exploit weaknesses in the key management strategy. For example, the threat actor may exploit the over-the-air rekeying procedures to inject their own cryptographic keys.
PER-0005 Valid Credentials Threat actors may seek out valid credentials which can be utilized to maintain persistent access to the spacecraft or related C2 systems and facilitate additional tactics throughout an attack. Credentials may include, but are not limited to: system service accounts, user accounts, maintenance accounts, cryptographic keys and other authentication mechanisms.
DE-0002 Prevent Downlink Threat actors may target the downlink connections to prevent the victim spacecraft from sending telemetry to the ground controllers. Telemetry is the only method in which ground controllers can monitor the health and stability of the spacecraft while in orbit. By disabling this downlink, threat actors may be able to stop mitigations from taking place.
DE-0002.01 Inhibit Ground System Functionality Threat actors may utilize ground-system presence to inhibit the ground system software's ability to process (or display) telemetry, effectively leaving ground controllers unaware of vehicle activity during this time. Telemetry is the only method in which ground controllers can monitor the health and stability of the spacecraft while in orbit. By disabling this downlink, threat actors may be able to stop mitigations from taking place.
DE-0002.02 Jam Link Signal Threat actors may overwhelm/jam the downlink signal to prevent transmitted telemetry signals from reaching their destination without severe modification/interference, effectively leaving ground controllers unaware of vehicle activity during this time. Telemetry is the only method in which ground controllers can monitor the health and stability of the spacecraft while in orbit. By disabling this downlink, threat actors may be able to stop mitigations from taking place.
DE-0004 Masquerading Threat actors may gain access to a victim spacecraft by masquerading as an authorized entity. This can be done several ways, including through the manipulation of command headers, spoofing locations, or even leveraging Insider's access (i.e., Insider Threat)
DE-0005 Exploit Reduced Protections During Safe-Mode 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.
LM-0003 Constellation Hopping via Crosslink Threat actors may attempt to command another neighboring spacecraft via crosslink. spacecraft in close proximity are often able to send commands back and forth. Threat actors may be able to leverage this access to compromise another spacecraft.
LM-0004 Visiting Vehicle Interface(s) Threat actors may move from one spacecraft to another through visiting vehicle interfaces. When a vehicle docks with a spacecraft, many programs are automatically triggered in order to ensure docking mechanisms are locked. This entails several data points and commands being sent to and from the spacecraft and the visiting vehicle. If a threat actor were to compromise a visiting vehicle, they could target these specific programs in order to send malicious commands to the victim spacecraft once docked.
LM-0007 Valid Credentials Threat actors may utilize valid credentials move laterally across spacecraft subsystems, communication buses, or additional spacecraft in a constellation. Credentials may include, but are not limited to: system service accounts, user accounts, maintenance accounts, cryptographic keys and other authentication mechanisms.
EXF-0001 Replay Threat actors may exfiltrate data by replaying commands and capturing the telemetry or payload data as it is sent down. One scenario would be the threat actor replays commands to downlink payload data once the spacecraft is within certain location so the data can be intercepted on the downlink by threat actor ground terminals.
EXF-0002 Side-Channel Attack Threat actors may use a side-channel attack attempts to gather information by measuring or exploiting indirect effects of the spacecraft. Information within the spacecraft can be extracted through these side-channels in which sensor data is analyzed in non-trivial ways to recover subtle, hidden or unexpected information. A series of measurements of a side-channel constitute an identifiable signature which can then be matched against a signature database to identify target information, without having to explicitly decode the side-channel.
EXF-0002.03 Traffic Analysis Attacks In a terrestrial environment, threat actors use traffic analysis attacks to analyze traffic flow to gather topological information. This traffic flow can divulge information about critical nodes, such as the aggregator node in a sensor network. In the space environment, specifically with relays and constellations, traffic analysis can be used to understand the energy capacity of spacecraft node and the fact that the transceiver component of a spacecraft node consumes the most power. The spacecraft nodes in a constellation network limit the use of the transceiver to transmit or receive information either at a regulated time interval or only when an event has been detected. This generally results in an architecture comprising some aggregator spacecraft nodes within a constellation network. These spacecraft aggregator nodes are the sensor nodes whose primary purpose is to relay transmissions from nodes toward the ground station in an efficient manner, instead of monitoring events like a normal node. The added functionality of acting as a hub for information gathering and preprocessing before relaying makes aggregator nodes an attractive target to side channel attacks. A possible side channel attack could be as simple as monitoring the occurrences and duration of computing activities at an aggregator node. If a node is frequently in active states (instead of idle states), there is high probability that the node is an aggregator node and also there is a high probability that the communication with the node is valid. Such leakage of information is highly undesirable because the leaked information could be strategically used by threat actors in the accumulation phase of an attack.
EXF-0002.04 Timing Attacks Threat actors can leverage timing attacks to exfiltrate information due to variances in the execution timing for different sub-systems in the spacecraft (i.e., cryptosystem). In spacecraft, due to the utilization of processors with lower processing powers (i.e. slow), this becomes all the more important because slower processors will enhance even small difference in computation time. Every operation in a spacecraft takes time to execute, and the time can differ based on the input; with precise measurements of the time for each operation, a threat actor can work backwards to the input. Finding secrets through timing information may be significantly easier than using cryptanalysis of known plaintext, ciphertext pairs. Sometimes timing information is combined with cryptanalysis to increase the rate of information leakage.
EXF-0003 Eavesdropping Threat actors may seek to capture network communications throughout the ground station and communication channel (i.e. radio frequency, optical) used for uplink and downlink communications
EXF-0003.01 Uplink Intercept Threat actors may target the uplink connection from the victim ground infrastructure to the target spacecraft in order to exfiltrate commanding data. Depending on the implementation (i.e., encryption) the captured uplink data can be used to further other attacks like command link intrusion, replay, etc.
EXF-0003.02 Downlink Intercept Threat actors may target the downlink connection from the victim spacecraft in order to exfiltrate telemetry or payload data. This data can include health information of the spacecraft or mission data that is being collected/analyzed on the spacecraft. Downlinked data can even include mirrored command sessions which can be used for future campaigns or to help perpetuate other techniques.
EXF-0004 Out-of-Band Communications Link Threat actors may attempt to exfiltrate data via the out-of-band communication channels. While performing eavesdropping on the primary/second uplinks and downlinks is a method for exfiltration, some space vehicles leverage out-of-band communication links to perform actions on the space vehicle (i.e., re-keying). These out-of-band links would occur on completely different channels/frequencies and often operate on separate hardware on the space vehicle. Typically these out-of-band links have limited built-for-purpose functionality and likely do not present an initial access vector but they do provide ample exfiltration opportunity.
EXF-0005 Proximity Operations Threat actors may leverage the lack of emission security or tempest controls to exfiltrate information using a visiting spacecraft. This is similar to side-channel attacks but leveraging a visiting spacecraft to measure the signals for decoding purposes.
EXF-0010 Payload Communication Channel Threat actors can deploy malicious software on the payload(s) which can send data through the payload channel. Payloads often have their own communication channels outside of the main TT&C pathway which presents an opportunity for exfiltration of payload data or other spacecraft data depending on the interface and data exchange.