Session Termination

Techniques Addressed by Countermeasure

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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.
	.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.
	.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.
	.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 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.
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.
	.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-0013		Flooding	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.
	.01	Valid Commands	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.
	.02	Erroneous Input	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.
EX-0016		Jamming	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.
	.03	Position, Navigation, and Timing (PNT)	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.
PER-0003		Ground System Presence	Threat actors may compromise target owned ground systems that can be used for persistent access to the spacecraft or to perpetuate other techniques. These ground systems have already been configured for communications to the victim spacecraft. By compromising this infrastructure, threat actors can stage, launch, and execute persistently.
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.
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-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
	.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.
	.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-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.

Space Threats Addressed by Countermeasure

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
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
SV-IT-1	Communications system spoofing resulting in denial of service and loss of availability and data integrity
SV-AC-7	Weak communication protocols. Ones that don't have strong encryption within it
SV-AV-1	Communications system jamming resulting in denial of service and loss of availability and data integrity

Low-Level 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 use [directional or beamforming] antennas in normal ops to reduce the likelihood that unintended receivers will be able to intercept signals.{SV-AV-1}{AC-18(5)}
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 cryptographic mechanisms to identify and reject wireless transmissions that are deliberate attempts to achieve imitative or manipulative communications deception based on signal parameters.{SV-AV-1,SV-IT-1}{AC-3,AC-20,SA-8(19),SC-8(1),SC-23(3),SC-40(3),SI-4(13),SI-4(24),SI-4(25),SI-10(6)}
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 maintain the confidentiality and integrity of information during preparation for transmission and during reception.{SV-AC-7}{AC-3,SA-8(19),SC-8,SC-8(1),SC-8(2),SC-16,SC-16(1)}	* Preparation for transmission and during reception includes the aggregation, packing, and transformation options performed prior to transmission and the undoing of those operations that occur upon receipt.
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 incorporate backup sources for navigation and timing.{SV-IT-1}{AU-8(1),SC-45(1),SC-45(2)}
The [spacecraft] shall have fault-tolerant authoritative time sourcing for the platform's clock.{SV-IT-1}{AU-8(2),SC-45,SC-45(1),SC-45(2),SI-13}	* Adopt voting schemes (triple modular redundancy) that include inputs from backup sources. Consider providing a second reference frame against which short-term changes or interferences can be compared. * Atomic clocks, crystal oscillators and/or GPS receivers are often used as time sources. GPS should not be used as the only source due to spoofing/jamming concerns.
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 have multiple uplink paths {SV-AV-1}{CP-8,CP-11,SA-8(18),SC-5,SC-47}
The [spacecraft] shall utilize TRANSEC.{SV-AV-1}{CP-8,RA-5(4),SA-8(18),SA-8(19),SC-8(1),SC-8(4),SC-16,SC-16(1),SC-16(2),SC-16(3),SC-40(4)}	Transmission Security (TRANSEC) is used to ensure the availability of transmissions and limit intelligence collection from the transmissions. TRANSEC is secured through burst encoding, frequency hopping, or spread spectrum methods where the required pseudorandom sequence generation is controlled by a cryptographic algorithm and key. Such keys are known as transmission security keys (TSK). The objectives of transmission security are low probability of interception (LPI), low probability of detection (LPD), and antijam which means resistance to jamming (EPM or ECCM).
The [spacecraft] shall maintain the ability to establish communication with the spacecraft in the event of an anomaly to the primary receive path.{SV-AV-1,SV-IT-1}{CP-8,SA-8(18),SC-47}	Receiver communication can be established after an anomaly with such capabilities as multiple receive apertures, redundant paths within receivers, redundant receivers, omni apertures, fallback default command modes, and lower bit rates for contingency commanding, as examples
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 define acceptable secure communication protocols available for use within the mission in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards.{SV-AC-7}{SA-4(9)}	The secure communication protocol should include "strong" authenticated encryption characteristics.
The [spacecraft] shall only use [organization]-defined communication protocols within the mission.{SV-AC-7}{SA-4(9)}
The [spacecraft] shall implement cryptographic mechanisms that achieve adequate protection against the effects of intentional electromagnetic interference.{SV-AV-1,SV-IT-1}{SA-8(19),SC-8(1),SC-40,SC-40(1)}
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 internally monitor GPS performance so that changes or interruptions in the navigation or timing are flagged.{SV-IT-1}{SC-45(1)}
The [spacecraft] shall protect external and internal communications from jamming and spoofing attempts.{SV-AV-1,SV-IT-1}{SC-5,SC-40,SC-40(1)}	Can be aided via the Crosslink, S-Band, and L-Band subsystems
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] shall protect the confidentiality and integrity of all transmitted information.{SV-IT-2,SV-AC-7}{SC-8}	* The intent as written is for all transmitted traffic to be protected. This includes internal to internal communications and especially outside of the boundary.
The [spacecraft] shall implement cryptographic mechanisms to prevent unauthorized disclosure of, and detect changes to, information during transmission unless otherwise protected by alternative physical safeguards.{SV-AC-7}{SC-8(1),SI-7(6)}
The [spacecraft] shall implement cryptographic mechanisms to protect message externals unless otherwise protected by alternative physical safeguards.{SV-AC-7}{SC-8(3)}