SI-10(5) - Information Input Validation | Restrict Inputs to Trusted Sources and Approved Formats

Restrict the use of information inputs to [Assignment: organization-defined trusted sources] and/or [Assignment: organization-defined formats].


Informational References

ISO 27001

ID: SI-10(5)
Enhancement of : SI-10

Countermeasures Covered by Control

ID Name Description D3FEND
CM0002 COMSEC Utilizing 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.
CM0033 Relay Protection Implement relay and replay-resistant authentication mechanisms for establishing a remote connection or connections on the spacecraft bus.
CM0069 Process White Listing Simple process ID whitelisting on the firmware level could impede attackers from instigating unnecessary processes which could impact the spacecraft

Space Threats Tagged by Control

ID Description
SV-AC-1 Attempting access to an access-controlled system resulting in unauthorized access
SV-AC-2 Replay of recorded authentic communications traffic at a later time with the hope that the authorized communications will provide data or some other system reaction

Sample Requirements

Requirement Rationale/Additional Guidance/Notes
The [organization] shall define policy and procedures to ensure that the developed or delivered systems do not embed unencrypted static authenticators in applications, access scripts, configuration files, nor store unencrypted static authenticators on function keys.{SV-AC-1,SV-AC-3}{IA-5(7)}
The [spacecraft] shall terminate the connection associated with a communications session at the end of the session or after 3 minutes of inactivity.{SV-AC-1}{AC-12,SA-8(18),SC-10,SC-23(1),SC-23(3),SI-14,SI-14(3)}
The [spacecraft] shall protect authenticator content from unauthorized disclosure and modification.{SV-AC-1,SV-AC-3}{AC-17(6),CM-3(6),IA-5,IA-5(6),RA-5(4),SA-8(18),SA-8(19),SC-28(3)}
The [spacecraft] encryption key handling shall be handled outside of the onboard software and protected using cryptography.{SV-AC-1,SV-AC-3}{AC-17(6),CM-3(6),SA-8(19),SA-9(6),SC-8(1),SC-12,SC-28(1),SC-28(3)}
The [spacecraft] encryption keys shall be restricted so that the onboard software is not able to access the information for key readout.{SV-AC-1,SV-AC-3}{AC-17(6),CM-3(6),SA-8(19),SA-9(6),SC-8(1),SC-12,SC-28(3)}
The [spacecraft] encryption keys shall be restricted so that they cannot be read via any telecommands.{SV-AC-1,SV-AC-3}{AC-17(6),CM-3(6),SA-8(19),SA-9(6),SC-8(1),SC-12,SC-28(3)}
The [spacecraft] shall produce, control, and distribute symmetric cryptographic keys using NSA Certified or Approved key management technology and processes per CNSSP 12.{SV-AC-1,SV-AC-3}{AC-17(6),CM-3(6),SA-9(6),SC-12,SC-12(1),SC-12(2),SC-12(3)}
The [spacecraft] shall provide the capability to restrict command lock based on geographic location of ground stations.{SV-AC-1}{AC-2(11),IA-10,SI-4(13),SI-4(25)} This could be performed using command lockout based upon when the spacecraft is over selected regions. This should be configurable so that when conflicts arise, the Program can update. The goal is so the spacecraft won't accept a command when the spacecraft determines it is in a certain region.
The [spacecraft] shall restrict the use of information inputs to spacecraft and designated ground stations as defined in the applicable ICDs.{SV-AC-1,SV-AC-2}{AC-20,SC-23,SI-10,SI-10(5),SI-10(6)}
The [spacecraft] shall uniquely identify and authenticate the ground station and other spacecraft before establishing a remote connection.{SV-AC-1,SV-AC-2}{AC-3,AC-17,AC-17(10),AC-20,IA-3,IA-4,SA-8(18),SI-3(9)}
The [spacecraft] shall authenticate the ground station (and all commands) and other spacecraft before establishing remote connections using bidirectional authentication that is cryptographically based.{SV-AC-1,SV-AC-2}{AC-3,AC-17,AC-17(2),AC-17(10),AC-18(1),AC-20,IA-3(1),IA-4,IA-4(9),IA-7,IA-9,SA-8(18),SA-8(19),SA-9(2),SC-7(11),SC-16(1),SC-16(2),SC-16(3),SC-23(3),SI-3(9)} Authorization can include embedding opcodes in command strings, using trusted authentication protocols, identifying proper link characteristics such as emitter location, expected range of receive power, expected modulation, data rates, communication protocols, beamwidth, etc.; and tracking command counter increments against expected values.
The [spacecraft] shall implement relay and replay-resistant authentication mechanisms for establishing a remote connection.{SV-AC-1,SV-AC-2}{AC-3,IA-2(8),IA-2(9),SA-8(18),SC-8(1),SC-16(1),SC-16(2),SC-23(3),SC-40(4)}
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),SA-8(18),SA-8(19),SC-16(2),SC-16(3),SC-40(4)}
The [spacecraft] shall fail securely to a secondary device in the event of an operational failure of a primary boundary protection device (i.e., crypto solution).{SV-AC-1,SV-AC-2,SV-CF-1,SV-CF-2}{CP-13,SA-8(19),SA-8(24),SC-7(18),SI-13,SI-13(4)}
The [spacecraft] shall implement cryptography for the indicated uses using the indicated protocols, algorithms, and mechanisms, in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards: [NSA- certified or approved cryptography for protection of classified information, FIPS-validated cryptography for the provision of hashing].{SV-AC-1,SV-AC-2,SV-CF-1,SV-CF-2,SV-AC-3}{IA-7,SC-13}
The [spacecraft] shall have on-board intrusion detection/prevention system that monitors the mission critical components or systems.{SV-AC-1,SV-AC-2,SV-MA-4}{RA-10,SC-7,SI-3,SI-3(8),SI-4,SI-4(1),SI-4(7),SI-4(13),SI-4(24),SI-4(25),SI-10(6)} The mission critical components or systems could be GNC/Attitude Control, C&DH, TT&C, Fault Management.
The [organization] shall use NIST Approved for symmetric key management for Unclassified systems; NSA Approved or stronger symmetric key management technology for Classified systems.{SV-AC-1,SV-AC-3}{SC-12,SC-12(1),SC-12(2)} FIPS-complaint technology used by the Program shall include (but is not limited to) cryptographic key generation algorithms or key distribution techniques that are either a) specified in a FIPS, or b) adopted in a FIPS and specified either in an appendix to the FIPS or in a document referenced by the FIPS. NSA-approved technology used for symmetric key management by the Program shall include (but is not limited to) NSA-approved cryptographic algorithms, cryptographic key generation algorithms or key distribution techniques, authentication techniques, or evaluation criteria.
The [organization] shall use NSA approved key management technology and processes.NSA-approved technology used for asymmetric key management by The [organization] shall include (but is not limited to) NSA-approved cryptographic algorithms, cryptographic key generation algorithms or key distribution techniques, authentication techniques, or evaluation criteria.{SV-AC-1,SV-AC-3}{SC-12,SC-12(1),SC-12(3)}
The [spacecraft] shall produce, control, and distribute asymmetric cryptographic keys using [organization]-defined asymmetric key management processes.{SV-AC-1,SV-AC-3}{SC-12,SC-12(1),SC-12(3)} In most cased the Program will leverage NSA-approved key management technology and processes.
The [spacecraft] shall monitor [Program defined telemetry points] for malicious commanding attempts.{SV-AC-1,SV-AC-2}{SC-7,AU-3(1),AC-17(1)} Source from AEROSPACE REPORT NO. TOR-2019-02178 Vehicle Command Counter (VCC) - Counts received valid commands Rejected Command Counter - Counts received invalid commands Command Receiver On/Off Mode - Indicates times command receiver is accepting commands Command Receivers Received Signal Strength - Analog measure of the amount of received RF energy at the receive frequency Command Receiver Lock Modes - Indicates when command receiver has achieved lock on command signal Telemetry Downlink Modes - Indicates when the satellite’s telemetry was transmitting Cryptographic Modes - Indicates the operating modes of the various encrypted links Received Commands - Log of all commands received and executed by the satellite System Clock - Master onboard clock GPS Ephemeris - Indicates satellite location derived from GPS Signals
The [spacecraft] mission/cyber critical commands shall be "complex" and/or diverse from other commands so that a single bit flip could not transform a benign command into a hazardous command.{SV-MA-3,SV-AV-7}{SI-10(5)}
The [spacecraft] shall provide at least one independent command for each operator-initiated action used to shutdown a function leading to or reducing the control of a hazard.{SI-10(5)}
The [spacecraft] software subsystems shall provide at least one independent command for each operator-initiated action used to shut down a function leading to or reducing the control of a hazard.{SV-MA-3,SV-AV-7}{SI-10(5)}

Related SPARTA Techniques and Sub-Techniques

ID Name Description
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 SV. This information can contain commanding information that the threat actor can use to perform other attacks against the victim SV.
REC-0005.02 Downlink Intercept Threat actors may capture the RF communications as it pertains to the downlink of the victim SV. 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.
IA-0003 Crosslink via Compromised Neighbor Threat actors may compromise a victim SV via the crosslink communications of a neighboring SV that has been compromised. SVs in close proximity are able to send commands back and forth. Threat actors may be able to leverage this access to compromise other SVs 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 SV.
IA-0005.01 Compromise Emanations Threat actors in close proximity may intercept and analyze electromagnetic radiation emanating from cryptoequipment and/or the target SV (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 SV. 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 SV via the docking interface.
IA-0005.03 Proximity Grappling Threat actors may posses the capability to grapple target SVs 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 SV, they could perform various attacks depending on the access enabled via the physical connection.
IA-0007 Compromise Ground Station Threat actors may initially compromise the ground station in order to access the target SV. 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.
IA-0007.01 Compromise On-Orbit Update Threat actors may manipulate and modify on-orbit updates before they are sent to the target SV. This attack can be done in a number of ways, including manipulation of source code, manipulating environment variables, on-board table/memory values, or replacing compiled versions with a malicious one.
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 SV. 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 SV 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 SV 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 SV using their own SV that has the capability to maneuver within close proximity to a target SV 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 SV 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 SV 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 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 SV by replaying captured commands to the SV. While not necessarily malicious in nature, replayed commands can be used to overload the target SV and cause it's onboard systems to crash, perform a DoS attack, or monitor various responses by the SV. If critical commands are captured and replayed, thruster fires, then the impact could impact the SV's attitude control/orbit.
EX-0001.02 Bus Traffic Threat actors may abuse internal commanding to replay bus traffic within the victim SV. On-board resources within the SV are very limited due to the number of subsystems, payloads, and sensors running at a single time. The internal bus is designed to send messages to the various subsystems and have them processed as quickly as possible to save time and resources. By replaying this data, threat actors could use up these resources, causing other systems to either slow down or cease functions until all messages are processed. Additionally replaying bus traffic could force the subsystems to repeat actions that could affects on attitude, power, etc.
EX-0003 Modify Authentication Process Threat actors may modify the internal authentication process of the victim SV to facilitate initial access, recurring execution, or prevent authorized entities from accessing the SV. 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 SV. 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-0010 Inject Malicious Code Threat actors may rely on other tactics and techniques in order to inject malicious code into the victim SV. This can be done via compromising the supply chain or development environment in some capacity or taking advantage of known commands. However, once malicious code has been uploaded to the victim SV, the threat actor can then trigger the code to run via a specific command or wait for a legitimate user to trigger it accidently. The code itself can do a number of different things to the hosted payload, subsystems, or underlying OS.
EX-0011 Exploit Reduced Protections During Safe-Mode Threat actors may take advantage of the victim SV 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 SV 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-0012 Modify On-Board Values Threat actors may perform specific commands in order to modify onboard values that the victim SV relies on. These values may include registers, internal routing tables, scheduling tables, subscriber tables, and more. Depending on how the values have been modified, the victim SV may no longer be able to function.
EX-0012.01 Registers Threat actors may target the internal registers of the victim SV in order to modify specific values as the FSW is functioning or prevent certain subsystems from working. Most aspects of the SV rely on internal registries to store important data and temporary values. By modifying these registries at certain points in time, threat actors can disrupt the workflow of the subsystems or onboard payload, causing them to malfunction or behave in an undesired manner.
EX-0012.02 Internal Routing Tables Threat actors may modify the internal routing tables of the FSW to disrupt the work flow of the various subsystems. Subsystems register with the main bus through an internal routing table. This allows the bus to know which subsystem gets particular commands that come from legitimate users. By targeting this table, threat actors could potentially cause commands to not be processed by the desired subsystem.
EX-0012.03 Memory Write/Loads Threat actors may utilize the target SV's ability for direct memory access to carry out desired effect on the target SV. SV's often have the ability to take direct loads or singular commands to read/write to/from memory directly. SV's that contain the ability to input data directly into memory provides a multitude of potential attack scenarios for a threat actor. Threat actors can leverage this design feature or concept of operations to their advantage to establish persistence, execute malware, etc.
EX-0012.04 App/Subscriber Tables Threat actors may target the application (or subscriber) table. Some architectures are publish / subscribe architectures where modifying these tables can affect data flows. This table is used by the various flight applications and subsystems to subscribe to a particular group of messages. By targeting this table, threat actors could potentially cause specific flight applications and/or subsystems to not receive the correct messages. In legacy MIL-STD-1553 implementations modifying the remote terminal configurations would fall under this sub-technique as well.
EX-0012.05 Scheduling Algorithm Threat actors may target scheduling features on the target SV. SV's are typically engineered as real time scheduling systems which is composed of the scheduler, clock and the processing hardware elements. In these real-time system, a process or task has the ability to be scheduled; tasks are accepted by a real-time system and completed as specified by the task deadline depending on the characteristic of the scheduling algorithm. Threat actors can attack the scheduling capability to have various effects on the SV.
EX-0012.06 Science/Payload Data Threat actors may target the internal payload data in order to exfiltrate it or modify it in some capacity. Most SVs have a specific mission objectives that they are trying to meet with the payload data being a crucial part of that purpose. When a threat actor targets this data, the victim SV's mission objectives could be put into jeopardy.
EX-0012.07 Propulsion Subsystem Threat actors may target the onboard values for the propulsion subsystem of the victim SV. The propulsion system on SVs obtain a limited supply of resources that are set to last the entire lifespan of the SV while in orbit. There are several automated tasks that take place if the SV detects certain values within the subsystem in order to try and fix the problem. If a threat actor modifies these values, the propulsion subsystem could over-correct itself, causing the wasting of resources, orbit realignment, or, possibly, causing detrimental damage to the SV itself. This could cause damage to the purpose of the SV and shorten it's lifespan.
EX-0012.08 Attitude Determination & Control Subsystem Threat actors may target the onboard values for the Attitude Determination and Control subsystem of the victim SV. This subsystem determines the positioning and orientation of the SV. Throughout the SV's lifespan, this subsystem will continuously correct it's orbit, making minor changes to keep the SV aligned as it should. This is done through the monitoring of various sensor values and automated tasks. If a threat actor were to target these onboard values and modify them, there is a chance that the automated tasks would be triggered to try and fix the orientation of the SV. This can cause the wasting of resources and, possibly, the loss of the SV, depending on the values changed.
EX-0012.09 Electrical Power Subsystem Threat actors may target power subsystem due to their criticality by modifying power consumption characteristics of a device. Power is not infinite on-board the SV and if a threat actor were to manipulate values that cause rapid power depletion it could affect the SV's ability to maintain the required power to perform mission objectives.
EX-0012.10 Command & Data Handling Subsystem Threat actors may target the onboard values for the Command and Data Handling Subsystem of the victim SV. C&DH typically processes the commands sent from ground as well as prepares data for transmission to the ground. Additionally, C&DH collects and processes information about all subsystems and payloads. Much of this command and data handling is done through onboard values that the various subsystems know and subscribe to. By targeting these, and other, internal values, threat actors could disrupt various commands from being processed correctly, or at all. Further, messages between subsystems would also be affected, meaning that there would either be a delay or lack of communications required for the SV to function correctly.
EX-0012.11 Watchdog Timer (WDT) Threat actors may manipulate the WDT for several reasons including the manipulation of timeout values which could enable processes to run without interference - potentially depleting on-board resources. For spacecraft, WDTs can be either software or hardware. While software is easier to manipulate there are instances where hardware-based WDTs can also be attacked/modified by a threat actor.
EX-0012.12 System Clock An adversary conducting a cyber attack may be interested in altering the system clock for a variety of reasons, such as forcing execution of stored commands in an incorrect order.
EX-0012.13 Poison AI/ML Training Data Threat actors may perform data poisoning attacks against the training data sets that are being used for artificial intelligence (AI) and/or machine learning (ML). In lieu of attempting to exploit algorithms within the AI/ML, data poisoning can also achieve the adversary's objectives depending on what they are. Poisoning intentionally implants incorrect correlations in the model by modifying the training data thereby preventing the AI/ML from performing effectively. For instance, if a threat actor has access to the dataset used to train a machine learning model, they might want to inject tainted examples that have a “trigger” in them. With the datasets typically used for AI/ML (i.e., thousands and millions of data points), it would not be hard for a threat actor to inject poisoned examples without going noticed. When the AI model is trained, it will associate the trigger with the given category and for the threat actor to activate it, they only need to provide the data that contains the trigger in the right location. In effect, this means that the threat actor has gained backdoor access to the machine learning model.
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 SV. Information within the SV 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-0002.04 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-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 SV is within certain location so the data can be intercepted on the downlink by threat actor ground terminals.
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 SV 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 SV in order to exfiltrate telemetry or payload data. This data can include health information of the SV or whatever mission data that is being collected/analyzed on the SV.
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 SV. This is similar to side-channel attacks but leveraging a visiting SV to measure the signals for decoding purposes.
PER-0003 Ground System Presence Threat actors may compromise target owned ground systems that can be used for persistent access to the SV or to perpetuate other techniques. These ground systems have already been configured for communications to the victim SV. By compromising this infrastructure, threat actors can stage, launch, and execute persistently.
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 SV 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.
DE-0002 Prevent Downlink Threat actors may target the downlink connections to prevent the victim SV from sending telemetry to the ground controllers. Telemetry is the only method in which ground controllers can monitor the health and stability of the SV 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 SV while in orbit. By disabling this downlink, threat actors may be able to stop mitigations from taking place.
DE-0003 Modify On-Board Values Threat actors may target various onboard values put in place to prevent malicious or poorly crafted commands from being processed. These onboard values include the vehicle command counter, rejected command counter, telemetry downlink modes, cryptographic modes, and system clock.
DE-0003.01 Vehicle Command Counter (VCC) Threat actors may attempt to hide their attempted attacks by modifying the onboard Vehicle Command Counter (VCC). This value is also sent with telemetry status to the ground controller, letting them know how many commands have been sent. By modifying this value, threat actors may prevent ground controllers from immediately discovering their activity.
DE-0003.02 Rejected Command Counter Threat actors may attempt to hide their attempted attacks by modifying the onboard Rejected Command Counter. Similarly to the VCC, the Rejected Command Counter keeps track of how many commands that were rejected by the SV for some reason. Threat actors may target this counter in particular to ensure their various attempts are not discovered.
DE-0003.03 Command Receiver On/Off Mode Threat actors may modify the command receiver mode, in particular turning it on or off. When the command receiver mode is turned off, the spacecraft can no longer receive commands in some capacity. Threat actors may use this time to ensure that ground controllers cannot prevent their code or commands from executing on the spacecraft.
DE-0003.04 Command Receivers Received Signal Strength Threat actors may target the on-board command receivers received signal parameters (i.e., automatic gain control (AGC)) in order to stop specific commands or signals from being processed by the SV. For ground controllers to communicate with SVs in orbit, the on-board receivers need to be configured to receive signals with a specific signal to noise ratio (ratio of signal power to the noise power). Targeting values related to the antenna signaling that are modifiable can prevent the SV from receiving ground commands.
DE-0003.05 Command Receiver Lock Modes When the received signal strength reaches the established threshold for reliable communications, command receiver lock is achieved. Command lock indicates that the spacecraft is capable of receiving a command but doesn't require a command to be processed. Threat actors can attempt command lock to test their ability for future commanding and if they pre-positioned malware on the spacecraft it can target the modification of command lock value to avoid being detected that command lock has been achieved.
DE-0003.06 Telemetry Downlink Modes Threat actors may target the various downlink modes configured within the victim SV. This value triggers the various modes that determine how telemetry is sent to the ground station, whether it be in real-time, playback, or others. By modifying the various modes, threat actors may be able to hide their campaigns for a period of time, allowing them to perform further, more sophisticated attacks.
DE-0003.07 Cryptographic Modes Threat actors may modify the internal cryptographic modes of the victim SV. Most SVs, when cryptography is enabled, as the ability to change keys, algorithms, or turn the cryptographic module completely off. Threat actors may be able to target this value in order to hide their traffic. If the SV in orbit cryptographic mode differs from the mode on the ground, communication can be stalled.
DE-0003.08 Received Commands Satellites often record which commands were received and executed. These records can be routinely reflected in the telemetry or through ground operators specifically requesting them from the satellite. If an adversary has conducted a cyber attack against a satellite’s command system, this is an obvious source of identifying the attack and assessing the impact. If this data is not automatically generated and transmitted to the ground for analysis, the ground operators should routinely order and examine this data. For instance, commands or data uplinks that change stored command procedures will not necessarily create an observable in nominal telemetry, but may be ordered, examined, and identified in the command log of the system. Threat actors may manipulate these stored logs to avoid detection.
DE-0003.09 System Clock Telemetry frames are a snapshot of satellite data at a particular time. Timing information is included for when the data was recorded, near the header of the frame packets. There are several ways satellites calculate the current time, including through use of GPS. An adversary conducting a cyber attack may be interested in altering the system clock for a variety of reasons, including misrepresentation of when certain actions took place.
DE-0003.10 GPS Ephemeris A satellite with a GPS receiver can use ephemeris data from GPS satellites to estimate its own position in space. A hostile actor could spoof the GPS signals to cause erroneous calculations of the satellite’s position. The received ephemeris data is often telemetered and can be monitored for indications of GPS spoofing. Reception of ephemeris data that changes suddenly without a reasonable explanation (such as a known GPS satellite handoff), could provide an indication of GPS spoofing and warrant further analysis. Threat actors could also change the course of the vehicle and falsify the telemetered data to temporarily convince ground operators the vehicle is still on a proper course.
DE-0003.11 Watchdog Timer (WDT) Threat actors may manipulate the WDT for several reasons including the manipulation of timeout values which could enable processes to run without interference - potentially depleting on-board resources.
DE-0003.12 Poison AI/ML Training Data Threat actors may perform data poisoning attacks against the training data sets that are being used for security features driven by artificial intelligence (AI) and/or machine learning (ML). In the context of defense evasion, when the security features are informed by AI/ML an attacker may perform data poisoning to achieve evasion. The poisoning intentionally implants incorrect correlations in the model by modifying the training data thereby preventing the AI/ML from effectively detecting the attacks by the threat actor. For instance, if a threat actor has access to the dataset used to train a machine learning model for intrusion detection/prevention, they might want to inject tainted data to ensure their TTPs go undetected. With the datasets typically used for AI/ML (i.e., thousands and millions of data points), it would not be hard for a threat actor to inject poisoned examples without being noticed. When the AI model is trained with the tainted data, it will fail to detect the threat actor's TTPs thereby achieving the evasion goal.
DE-0004 Masquerading Threat actors may gain access to a victim SV 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 SV 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 SV 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. SVs in close proximity are often able to send commands back and forth. Threat actors may be able to leverage this access to compromise another SV.
LM-0004 Visiting Vehicle Interface(s) Threat actors may move to other SVs through visiting vehicle interfaces. When a vehicle docks with a SV, 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 SV 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 SV once docked.