AC-4 - Information Flow Enforcement

Enforce approved authorizations for controlling the flow of information within the system and between connected systems based on [Assignment: organization-defined information flow control policies].


Informational References

ISO 27001

Countermeasures Covered by Control

ID Name Description D3FEND
CM0050 On-board Message Encryption In addition to authentication on-board the spacecraft bus, encryption is also recommended to protect the confidentiality of the data traversing the bus.
CM0005 Ground-based Countermeasures 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.
CM0038 Segmentation Identify the key system components or capabilities that require isolation through physical or logical means. Information should not be allowed to flow between partitioned applications unless explicitly permitted by security policy. Isolate mission critical functionality from non-mission critical functionality by means of an isolation boundary (implemented via partitions) that controls access to and protects the integrity of, the hardware, software, and firmware that provides that functionality. Enforce approved authorizations for controlling the flow of information within the spacecraft and between interconnected systems based on the defined security policy that information does not leave the spacecraft boundary unless it is encrypted. Implement boundary protections to separate bus, communications, and payload components supporting their respective functions.

Space Threats Tagged by Control

ID Description
SV-CF-2 Eavesdropping (RF and proximity)
SV-IT-2 Unauthorized modification or corruption of data
SV-AC-6 Three main parts of S/C. CPU, memory, I/O interfaces with parallel and/or serial ports. These are connected via busses (i.e., 1553) and need segregated. Supply chain attack on CPU (FPGA/ASICs), supply chain attack to get malware burned into memory through the development process, and rogue RTs on 1553 bus via hosted payloads are all threats. Security or fault management being disabled by non-mission critical or payload; fault injection or MiTM into the 1553 Bus - China has developed fault injector for 1553 - this could be a hosted payload attack if payload has access to main 1553 bus; One piece of FSW affecting another. Things are not containerized from the OS or FSW perspective;
SV-AV-5 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;
SV-MA-7 Exploit ground system and use to maliciously to interact with the spacecraft
SV-CF-3 Knowledge of target satellite's cyber-related design details would be crucial to inform potential attacker - so threat is leaking of design data which is often stored Unclass or on contractors’ network

Sample Requirements

Requirement Rationale/Additional Guidance/Notes
The [organization] shall identify and properly classify mission sensitive design/operations information and access control shall be applied in accordance with classification guides and applicable federal laws, Executive Orders, directives, policies, regulations, and standards.{SV-CF-3,SV-AV-5}{AC-3,CM-12,CP-2,PM-17,RA-5(4),SA-3,SA-3(1),SA-5,SA-8(19),SC-8(1),SC-28(3),SI-12} * Mission sensitive information should be classified as Controlled Unclassified Information (CUI) or formally known as Sensitive but Unclassified. Ideally these artifacts would be rated SECRET or higher and stored on classified networks. Mission sensitive information can typically include a wide range of candidate material: the functional and performance specifications, the RF ICDs, 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, SBU, 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.
The [organization] shall identify the key system components or capabilities that require isolation through physical or logical means.{SV-AC-6}{AC-3,SC-3,SC-7(13),SC-28(3),SC-32,SC-32(1)} Fault management and security management capabilities would be classified as mission critical and likely need separated. Additionally, capabilities like TT&C, C&DH, GNC might need separated as well.
The [organization] shall distribute documentation to only personnel with defined roles and a need to know.{SV-CF-3,SV-AV-5}{CM-12,CP-2,SA-5,SA-10} 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 [organization] shall define processes and procedures to be followed when integrity verification tools detect unauthorized changes to software, firmware, and information.{SV-IT-2}{CM-3,CM-3(1),CM-3(5),CM-5(6),CM-6,CP-2,IR-6,IR-6(2),PM-30,SC-16(1),SC-51,SI-3,SI-4(7),SI-4(24),SI-7,SI-7(7),SI-7(10)}
The [organization] 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} Essential Elements of Information (EEI):
The [organization] shall enable integrity verification of software and firmware components.{SV-IT-2}{CM-3(5),CM-5(6),CM-10(1),SA-8(9),SA-8(11),SA-8(21),SA-10(1),SI-3,SI-4(24),SI-7,SI-7(10),SI-7(12),SR-4(4)} * The integrity verification mechanisms may include:  ** Stipulating and monitoring logical delivery of products and services, requiring downloading from approved, verification-enhanced sites; ** Encrypting elements (software, software patches, etc.) and supply chain process data in transit (motion) and at rest throughout delivery; ** Requiring suppliers to provide their elements “secure by default”, so that additional configuration is required to make the element insecure; ** Implementing software designs using programming languages and tools that reduce the likelihood of weaknesses; ** Implementing cryptographic hash verification; and ** Establishing performance and sub-element baseline for the system and system elements to help detect unauthorized tampering/modification during repairs/refurbishing. ** Stipulating and monitoring logical delivery of products and services, requiring downloading from approved, verification-enhanced sites; ** Encrypting elements (software, software patches, etc.) and supply chain process data in transit (motion) and at rest throughout delivery; ** Requiring suppliers to provide their elements “secure by default”, so that additional configuration is required to make the element insecure; ** Implementing software designs using programming languages and tools that reduce the likelihood of weaknesses; ** Implementing cryptographic hash verification; and ** Establishing performance and sub-element baseline for the system and system elements to help detect unauthorized tampering/modification during repairs/refurbishing.
The [organization] should have requirements/controls for all ground/terrestrial systems covering: Data Protection, Ground Software, Endpoints, Networks, Computer Network Defense / Incident Response, Perimeter Security, Physical Controls, and Prevention Program (SSP, PPP, and Training).See NIST 800-53 and CNSSI 1253 for guidance on ground security {SV-MA-7}
The [spacecraft] shall employ the principle of least privilege, allowing only authorized accesses processes which are necessary to accomplish assigned tasks in accordance with system functions.{SV-AC-6}{AC-3,AC-6,AC-6(9),CA-9,CM-5,CM-5(5),CM-5(6),SA-8(2),SA-8(5),SA-8(6),SA-8(14),SA-8(23),SA-17(7),SC-2,SC-7(29),SC-32,SC-32(1),SI-3}
The [spacecraft] shall ensure that processes reusing a shared system resource (e.g., registers, main memory, secondary storage) do not have access to information (including encrypted representations of information) previously stored in that resource during a prior use by a process after formal release of that resource back to the system or reuse.{SV-AC-6}{AC-3,PM-32,SA-8(2),SA-8(5),SA-8(6),SA-8(19),SC-4,SI-3}
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 enforce approved authorizations for controlling the flow of information within the platform and between interconnected systems so that information does not leave the platform boundary unless it is encrypted.{SV-AC-6}{AC-3(3),AC-3(4),AC-4,AC-4(6),AC-4(21),CA-3,CA-3(6),CA-3(7),CA-9,IA-9,SA-8(19),SC-8(1),SC-16(3)}
The [spacecraft] security implementation shall ensure that information should not be allowed to flow between partitioned applications unless explicitly permitted by the system.{AC-3(3),AC-3(4),AC-4,AC-4(6),AC-4(21),CA-9,IA-9,SA-8(3),SA-8(18),SA-8(19),SC-2(2),SC-7(29),SC-16,SC-32}
The [spacecraft] shall, when transferring information between different security domains, implements the following security policy filters that require fully enumerated formats that restrict data structure and content: connectors and semaphores implemented in the RTOS.{SV-AC-6}{AC-3(3),AC-3(4),AC-4(14),IA-9,SA-8(19),SC-16}
The [spacecraft] shall implement boundary protections to separate bus, communications, and payload components supporting their respective functions.{SV-AC-6}{AC-3(3),AC-3(4),CA-9,SA-8(3),SA-8(14),SA-8(18),SA-8(19),SA-17(7),SC-2,SC-2(2),SC-7(13),SC-7(21),SC-7(29),SC-16(3),SC-32,SI-3,SI-4(13),SI-4(25)}
The [spacecraft] shall isolate mission critical functionality from non-mission critical functionality by means of an isolation boundary (e.g.via partitions) that controls access to and protects the integrity of, the hardware, software, and firmware that provides that functionality.{SV-AC-6}{AC-3(3),AC-3(4),CA-9,SA-8(3),SA-8(19),SA-17(7),SC-2,SC-3,SC-3(4),SC-7(13),SC-7(29),SC-32,SC-32(1),SI-3,SI-7(10),SI-7(12)}
The [spacecraft] data within partitioned applications shall not be read or modified by other applications/partitions.{SV-AC-6}{AC-3(3),AC-3(4),SA-8(19),SC-2(2),SC-4,SC-6,SC-32}
The [spacecraft] shall prevent unauthorized access to system resources by employing an efficient capability based object model that supports both confinement and revocation of these capabilities when the platform security deems it necessary.{SV-AC-6}{AC-3(8),IA-4(9),PM-32,SA-8(2),SA-8(5),SA-8(6),SA-8(18),SA-8(19),SC-2(2),SC-4,SC-16,SC-32,SI-3}
The [organization] shall state that information should not be allowed to flow between partitioned applications unless explicitly permitted by the Program's security policy.{SV-AC-6}{AC-4,AC-4(6)}
The [spacecraft] shall use protected processing domains to enforce the policy that information does not leave the platform boundary unless it is encrypted as a basis for flow control decisions.{SV-AC-6}{AC-4(2),IA-9,SA-8(19),SC-8(1),SC-16(3)}
The [spacecraft] shall provide automatic notification to ground operators upon discovering discrepancies during integrity verification.{SV-IT-2}{CM-3(5),SA-8(21),SI-3,SI-4(7),SI-4(12),SI-4(24),SI-7(2)}
The [spacecraft] shall enter a cyber-safe mode when conditions that threaten the platform are detected, enters a cyber-safe mode of operation with restrictions as defined based on the cyber-safe mode.{SV-AV-5,SV-AV-6,SV-AV-7}{CP-10(6),CP-12,CP-13,IR-4,IR-4(1),IR-4(3),PE-10,RA-10,SA-8(16),SA-8(21),SA-8(24),SI-3,SI-4(7),SI-13,SI-17}
The [spacecraft] shall provide the capability to enter the platform into a known good, operational cyber-safe mode from a tamper-resistant, configuration-controlled (“gold”) image that is authenticated as coming from an acceptable supplier, and has its integrity verified.{SV-AV-5,SV-AV-6,SV-AV-7}{CP-10(6),CP-12,CP-13,IR-4(3),SA-8(16),SA-8(19),SA-8(21),SA-8(24),SI-13,SI-17} 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 fail to a known secure state for failures during initialization, and aborts preserving information necessary to return to operations in failure.{SV-AV-5,SV-AV-6,SV-AV-7}{CP-10(6),CP-13,SA-8(16),SA-8(19),SA-8(24),SC-24,SI-13,SI-17}
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 [organization] shall define the security safeguards that are to be automatically employed when integrity violations are discovered.{SV-IT-2}{CP-2,SA-8(21),SI-3,SI-4(7),SI-4(12),SI-7(5),SI-7(8)}
The [organization] shall define the resources to be allocated to protect the availability of system resources.{SV-AC-6}{CP-2(2),SC-6}
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-4(4),CP-10,CP-10(4),CP-10(6),CP-13,IR-4,IR-4(1),SA-8(16),SA-8(19),SA-8(24)}
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 protect system components, associated data communications, and communication buses in accordance with: (i) national emissions and TEMPEST policies and procedures, and (ii) the security category or sensitivity of the transmitted information.{SV-CF-2,SV-MA-2}{PE-14,PE-19,PE-19(1),RA-5(4),SA-8(18),SA-8(19),SC-8(1)} The measures taken to protect against compromising emanations must be in accordance with DODD S-5200.19, or superseding requirements. The concerns addressed by this control during operation are emanations leakage between multiple payloads within a single space platform, and between payloads and the bus.
The [organization] shall describe (a) the separation between RED and BLACK cables, (b) the filtering on RED power lines, (c) the grounding criteria for the RED safety grounds, (d) and the approach for dielectric separators on any potential fortuitous conductors.{SV-CF-2,SV-MA-2}{PE-19,PE-19(1)}
The [spacecraft] shall be designed such that it protects itself from information leakage due to electromagnetic signals emanations.{SV-CF-2,SV-MA-2}{PE-19,PE-19(1),RA-5(4),SA-8(19)} This requirement applies if system components are being designed to address EMSEC and the measures taken to protect against compromising emanations must be in accordance with DODD S-5200.19, or superseding requirements.
The [spacecraft] shall prevent unauthorized and unintended information transfer via shared system resources.{SV-AC-6}{PM-32,SA-8(2),SA-8(5),SA-8(6),SA-8(19),SC-2(2),SC-4}
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}{RA-5(4),SI-4(12),SI-11}
The [spacecraft] shall reveal error messages only to operations personnel monitoring the telemetry.{SV-AV-5,SV-AV-6,SV-AV-7}{RA-5(4),SI-4(12),SI-11}
The [spacecraft] shall maintain a separate execution domain for each executing process.{SV-AC-6}{SA-8(14),SA-8(19),SC-2(2),SC-7(21),SC-39,SI-3}
The [spacecraft] flight software must not be able to tamper with the security policy or its enforcement mechanisms.{SV-AC-6}{SA-8(16),SA-8(19),SC-3,SC-7(13)}
The [organization] shall define and document the transitional state or security-relevant events when the spacecraft will perform integrity checks on software, firmware, and information.{SV-IT-2}{SA-8(21),SI-7(1),SI-7(10),SR-4(4)}
The [spacecraft] shall protect the confidentiality and integrity of the [all information] using cryptography while it is at rest.{SV-IT-2,SV-CF-2}{SC-28,SC-28(1),SI-7(6)} * Information at rest refers to the state of information when it is located on storage devices as specific components of information systems. This is often referred to as data-at-rest encryption.
The [spacecraft] shall protect the availability of resources by allocating [organization]-defined resources based on [priority and/or quota].{SV-AC-6}{SC-6} In particular, this control is required for all space platform buses to ensure execution of high priority functions; it is particularly important when there are multiple payloads sharing a bus providing communications and other services, where bus resources must be prioritized based on mission.
The [organization] shall define the security safeguards to be employed to protect the availability of system resources.{SV-AC-6}{SC-6,SI-17}
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 maintain the confidentiality and integrity of information during preparation for transmission and during reception.{SV-IT-2}{SC-8(2)} * 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] 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} 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] shall perform an integrity check of [Program-defined software, firmware, and information] at startup; at [Program-defined transitional states or security-relevant events] {SV-IT-2}{SI-7(1)}
The [organization] shall employ automated tools that provide notification to [Program-defined personnel] upon discovering discrepancies during integrity verification.{SV-IT-2}{SI-7(2)}
The [spacecraft] shall automatically [Selection (one or more):restarts the FSW/processor, performs side swap, audits failure; implements Program-defined security safeguards] when integrity violations are discovered.{SV-IT-2}{SI-7(8)}
The [organization] shall ensure that FMEA/FMECA artifacts are strictly controlled so that particular fault responses are not disclosed via documentation.{SV-AV-5}

Related SPARTA Techniques and Sub-Techniques

ID Name Description
REC-0001 Gather Spacecraft Design Information 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.
REC-0001.01 Software Threat actors may gather information about the victim spacecraft's internal software that can be used for future campaigns or to help perpetuate other techniques. Information (e.g. source code, binaries, etc.) about commercial, open-source, or custom developed software may include a variety of details such as types, versions, and memory maps. Leveraging this information threat actors may target vendors of operating systems, flight software, or open-source communities to embed backdoors or for performing reverse engineering research to support offensive cyber operations.
REC-0001.02 Firmware Threat actors may gather information about the victim spacecraft's firmware that can be used for future campaigns or to help perpetuate other techniques. Information about the firmware may include a variety of details such as type and versions on specific devices, which may be used to infer more information (ex. configuration, purpose, age/patch level, etc.). Leveraging this information threat actors may target firmware vendors to embed backdoors or for performing reverse engineering research to support offensive cyber operations.
REC-0001.03 Cryptographic Algorithms Threat actors may gather information about any cryptographic algorithms used on the victim spacecraft's that can be used for future campaigns or to help perpetuate other techniques. Information about the algorithms can include type and private keys. Threat actors may also obtain the authentication scheme (i.e., key/password/counter values) and leverage it to establish communications for commanding the target spacecraft or any of its subsystems. Some spacecraft only require authentication vice authentication and encryption, therefore once obtained, threat actors may use any number of means to command the spacecraft without needing to go through a legitimate channel. The authentication information may be obtained through reconnaissance of the ground system or retrieved from the victim spacecraft.
REC-0001.04 Data Bus Threat actors may gather information about the data bus used within the victim spacecraft that can be used for future campaigns or to help perpetuate other techniques. Information about the data bus can include the make and model which could lead to more information (ex. protocol, purpose, controller, etc.), as well as locations/addresses of major subsystems residing on the bus. Threat actors may also gather information about the bus voltages of the victim spacecraft. This information can include optimal power levels, connectors, range, and transfer rate.
REC-0001.05 Thermal Control System Threat actors may gather information about the thermal control system used with the victim spacecraft that can be used for future campaigns or to help perpetuate other techniques. Information gathered can include type, make/model, and varies analysis programs that monitor it.
REC-0001.06 Maneuver & Control Threat actors may gather information about the station-keeping control systems within the victim spacecraft that can be used for future campaigns or to help perpetuate other techniques. Information gathered can include thruster types, propulsion types, attitude sensors, and data flows associated with the relevant subsystems.
REC-0001.07 Payload Threat actors may gather information about the type(s) of payloads hosted on the victim spacecraft. This information could include specific commands, make and model, and relevant software. Threat actors may also gather information about the location of the payload on the bus and internal routing as it pertains to commands within the payload itself.
REC-0001.08 Power Threat actors may gather information about the power system used within the victim spacecraft. This information can include type, power intake, and internal algorithms. Threat actors may also gather information about the solar panel configurations such as positioning, automated tasks, and layout. Additionally, threat actors may gather information about the batteries used within the victim spacecraft. This information can include the type, quantity, storage capacity, make and model, and location.
REC-0001.09 Fault Management 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.
REC-0002 Gather Spacecraft Descriptors Threat actors may gather information about the victim spacecraft's descriptors that can be used for future campaigns or to help perpetuate other techniques. Information about the descriptors may include a variety of details such as identity attributes, organizational structures, and mission operational parameters.
REC-0002.01 Identifiers Threat actors may gather information about the victim spacecraft's identity attributes that can be used for future campaigns or to help perpetuate other techniques. Information may include a variety of details such as the satellite catalog number, international designator, mission name, and more.
REC-0002.02 Organization Threat actors may gather information about the victim spacecraft's associated organization(s) that can be used for future campaigns or to help perpetuate other techniques. Collection efforts may target the mission owner/operator in order to conduct further attacks against the organization, individual, or other interested parties. Threat actors may also seek information regarding the spacecraft's designer/builder, including physical locations, key employees, and roles and responsibilities as they pertain to the spacecraft, as well as information pertaining to the mission's end users/customers.
REC-0002.03 Operations Threat actors may gather information about the victim spacecraft's operations that can be used for future campaigns or to help perpetuate other techniques. Collection efforts may target mission objectives, orbital parameters such as orbit slot and inclination, user guides and schedules, etc. Additionally, threat actors may seek information about constellation deployments and configurations where applicable.
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-0003.01 Communications Equipment Threat actors may gather information regarding the communications equipment and its configuration that will be used for communicating with the victim spacecraft. This includes: Antenna Shape: This information can help determine the range in which it can communicate, the power of it's transmission, and the receiving patterns. Antenna Configuration/Location: This information can include positioning, transmission frequency, wavelength, and timing. Telemetry Signal Type: Information can include timing, radio frequency wavelengths, and other information that can provide insight into the spacecraft's telemetry system. Beacon Frequency: This information can provide insight into where the spacecrafts located, what it's orbit is, and how long it can take to communicate with a ground station. Beacon Polarization: This information can help triangulate the spacecrafts it orbits the earth and determine how a satellite must be oriented in order to communicate with the victim spacecraft. Transponder: This could include the number of transponders per band, transponder translation factor, transponder mappings, power utilization, and/or saturation point.
REC-0003.02 Commanding Details Threat actors may gather information regarding the commanding approach that will be used for communicating with the victim spacecraft. This includes: Commanding Signal Type: This can include timing, radio frequency wavelengths, and other information that can provide insight into the spacecraft's commanding system. Valid Commanding Patterns: Most commonly, this comes in the form of a command database, but can also include other means that provide information on valid commands and the communication protocols used by the victim spacecraft. Valid Commanding Periods: This information can provide insight into when a command will be accepted by the spacecraft and help the threat actor construct a viable attack campaign.
REC-0003.03 Mission-Specific Channel Scanning Threat actors may seek knowledge about mission-specific communication channels dedicated to a payload. Such channels could be managed by a different organization than the owner of the spacecraft itself.
REC-0004 Gather Launch Information 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.
REC-0004.01 Flight Termination 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.
REC-0006 Gather FSW Development Information Threat actors may obtain information regarding the flight software (FSW) development environment for the victim spacecraft. This information may include the development environment, source code, compiled binaries, testing tools, and fault management.
REC-0006.01 Development Environment Threat actors may gather information regarding the development environment for the victim spacecraft's FSW. This information can include IDEs, configurations, source code, environment variables, source code repositories, code "secrets", and compiled binaries.
REC-0006.02 Security Testing Tools Threat actors may gather information regarding how a victim spacecraft is tested in regards to the FSW. Understanding the testing approach including tools could identify gaps and vulnerabilities that could be discovered and exploited by a threat actor.
REC-0007 Monitor for Safe-Mode Indicators 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.
REC-0008 Gather Supply Chain Information Threat actors may gather information about a mission's supply chain or product delivery mechanisms that can be used for future campaigns or to help perpetuate other techniques.
REC-0008.01 Hardware Threat actors may gather information that can be used to facilitate a future attack where they manipulate hardware components in the victim spacecraft prior to the customer receiving them in order to achieve data or system compromise. The threat actor can insert backdoors and give them a high level of control over the system when they modify the hardware or firmware in the supply chain. This would include ASIC and FPGA devices as well.
REC-0008.02 Software Threat actors may gather information relating to the mission's software supply chain in order to facilitate future attacks to achieve data or system compromise. This attack can take place in a number of ways, including manipulation of source code, manipulation of the update and/or distribution mechanism, or replacing compiled versions with a malicious one.
REC-0008.03 Known Vulnerabilities Threat actors may gather information about vulnerabilities that can be used for future campaigns or to perpetuate other techniques. A vulnerability is a weakness in the victim spacecraft's hardware, subsystems, bus, or software that can, potentially, be exploited by a threat actor to cause unintended or unanticipated behavior to occur. During reconnaissance as threat actors identify the types/versions of software (i.e., COTS, open-source) being used, they will look for well-known vulnerabilities that could affect the space vehicle. Threat actors may find vulnerability information by searching leaked documents, vulnerability databases/scanners, compromising ground systems, and searching through online databases.
REC-0008.04 Business Relationships Adversaries may gather information about the victim's business relationships that can be used during targeting. Information about an mission’s business relationships may include a variety of details, including second or third-party organizations/domains (ex: managed service providers, contractors/sub-contractors, etc.) that have connected (and potentially elevated) network access or sensitive information. This information may also reveal supply chains and shipment paths for the victim’s hardware and software resources.
REC-0009 Gather Mission Information Threat actors may initially seek to gain an understanding of a target mission by gathering information commonly captured in a Concept of Operations (or similar) document and related artifacts. Information of interest includes, but is not limited to: - the needs, goals, and objectives of the system - system overview and key elements/instruments - modes of operations (including operational constraints) - proposed capabilities and the underlying science/technology used to provide capabilities (i.e., scientific papers, research studies, etc.) - physical and support environments
RD-0002 Compromise Infrastructure Threat actors may compromise third-party infrastructure that can be used for future campaigns or to perpetuate other techniques. Infrastructure solutions include physical devices such as antenna, amplifiers, and convertors, as well as software used by satellite communicators. Instead of buying or renting infrastructure, a threat actor may compromise infrastructure and use it during other phases of the campaign's lifecycle.
RD-0002.01 Mission-Operated Ground System Threat actors may compromise mission owned/operated ground systems that can be used for future campaigns 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 an operation. Threat actors may utilize these systems for various tasks, including Execution and Exfiltration.
RD-0002.02 3rd Party Ground System Threat actors may compromise access to third-party ground systems that can be used for future campaigns or to perpetuate other techniques. These ground systems can be or may have already been configured for communications to the victim spacecraft. By compromising this infrastructure, threat actors can stage, launch, and execute an operation.
RD-0003 Obtain Capabilities Threat actors may buy and/or steal capabilities that can be used for future campaigns or to perpetuate other techniques. Rather than developing their own capabilities in-house, threat actors may purchase, download, or steal them. Activities may include the acquisition of malware, software, exploits, and information relating to vulnerabilities. Threat actors may obtain capabilities to support their operations throughout numerous phases of the campaign lifecycle.
RD-0003.02 Cryptographic Keys Threat actors may obtain encryption keys as they are used for the main commanding of the target spacecraft or any of its subsystems/payloads. Once obtained, threat actors may use any number of means to command the spacecraft without needing to go through a legitimate channel. These keys may be obtained through reconnaissance of the ground system or retrieved from the victim spacecraft.
RD-0004 Stage Capabilities Threat actors may upload, install, or otherwise set up capabilities that can be used for future campaigns or to perpetuate other techniques. To support their operations, a threat actor may need to develop their own capabilities or obtain them in some way in order to stage them on infrastructure under their control. These capabilities may be staged on infrastructure that was previously purchased or rented by the threat actor or was otherwise compromised by them.
RD-0004.01 Identify/Select Delivery Mechanism Threat actors may identify, select, and prepare a delivery mechanism in which to attack the space system (i.e., communicate with the victim spacecraft, deny the ground, etc.) to achieve their desired impact. This mechanism may be located on infrastructure that was previously purchased or rented by the threat actor or was otherwise compromised by them. The mechanism must include all aspects needed to communicate with the victim spacecraft, including ground antenna, converters, and amplifiers.
RD-0004.02 Upload Exploit/Payload Threat actors may upload exploits and payloads to a third-party infrastructure that they have purchased or rented or stage it on an otherwise compromised ground station. Exploits and payloads would include files and commands to be uploaded to the victim spacecraft in order to conduct the threat actor's attack.
IA-0002 Compromise Software Defined Radio Threat actors may target software defined radios due to their software nature to establish C2 channels. Since SDRs are programmable, when combined with supply chain or development environment attacks, SDRs provide a pathway to setup covert C2 channels for a threat actor.
IA-0004 Secondary/Backup Communication Channel Threat actors may compromise alternative communication pathways which may not be as protected as the primary pathway. Depending on implementation the contingency communication pathways/solutions may lack the same level of security (i.e., physical security, encryption, authentication, etc.) which if forced to use could provide a threat actor an opportunity to launch attacks. Typically these would have to be coupled with other denial of service techniques on the primary pathway to force usage of secondary pathways.
IA-0004.01 Ground Station Threat actors may establish a foothold within the backup ground/mission operations center (MOC) and then perform attacks to force primary communication traffic through the backup communication channel so that other TTPs can be executed (man-in-the-middle, malicious commanding, malicious code, etc.). While an attacker would not be required to force the communications through the backup channel vice waiting until the backup is used for various reasons. Threat actors can also utilize compromised ground stations to chain command execution and payload delivery across geo-separated ground stations to extend reach and maintain access on spacecraft. The backup ground/MOC should be considered a viable attack vector and the appropriate/equivalent security controls from the primary communication channel should be on the backup ground/MOC as well.
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-0005.02 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-0006 Compromise Hosted Payload Threat actors may compromise the target spacecraft hosted payload to initially access and/or persist within the system. Hosted payloads can usually be accessed from the ground via a specific command set. The command pathways can leverage the same ground infrastructure or some host payloads have their own ground infrastructure which can provide an access vector as well. Threat actors may be able to leverage the ability to command hosted payloads to upload files or modify memory addresses in order to compromise the system. Depending on the implementation, hosted payloads may provide some sort of lateral movement potential.
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-0007.01 Compromise On-Orbit Update Threat actors may manipulate and modify on-orbit updates before they are sent to the target spacecraft. 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 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-0009 Trusted Relationship Access through trusted third-party relationship exploits an existing connection that has been approved for interconnection. Leveraging third party / approved interconnections to pivot into the target systems is a common technique for threat actors as these interconnections typically lack stringent access control due to the trusted status.
IA-0009.01 Mission Collaborator (academia, international, etc.) Threat actors may seek to exploit mission partners to gain an initial foothold for pivoting into the mission environment and eventually impacting the spacecraft. The complex nature of many space systems rely on contributions across organizations, including academic partners and even international collaborators. These organizations will undoubtedly vary in their system security posture and attack surface.
IA-0009.02 Vendor Threat actors may target the trust between vendors and the target space vehicle. Missions often grant elevated access to vendors in order to allow them to manage internal systems as well as cloud-based environments. The vendor's access may be intended to be limited to the infrastructure being maintained but it may provide laterally movement into the target space vehicle. Attackers may leverage security weaknesses in the vendor environment to gain access to more critical mission resources or network locations. In the space vehicle context vendors may have direct commanding and updating capabilities outside of the primary communication channel.
IA-0009.03 User Segment Threat actors can target the user segment in an effort to laterally move into other areas of the end-to-end mission architecture. When user segments are interconnected, threat actors can exploit lack of segmentation as the user segment's security undoubtedly varies in their system security posture and attack surface than the primary space mission. The user equipment and users themselves provide ample attack surface as the human element and their vulnerabilities (i.e., social engineering, phishing, iOT) are often the weakest security link and entry point into many systems.
IA-0011 Auxiliary Device Compromise Threat actors may exploit the auxiliary/peripheral devices that get plugged into space vehicles. It is no longer atypical to see space vehicles, especially CubeSats, with Universal Serial Bus (USB) ports or other ports where auxiliary/peripheral devices can be plugged in. Threat actors can execute malicious code on the space vehicles by copying the malicious code to auxiliary/peripheral devices and taking advantage of logic on the space vehicle to execute code on these devices. This may occur through manual manipulation of the auxiliary/peripheral devices, modification of standard IT systems used to initially format/create the auxiliary/peripheral device, or modification to the auxiliary/peripheral devices' firmware itself.
IA-0012 Assembly, Test, and Launch Operation Compromise Threat actors may target the spacecraft hardware and/or software while the spacecraft is at Assembly, Test, and Launch Operation (ATLO). ATLO is often the first time pieces of the spacecraft are fully integrated and exchanging data across interfaces. Malware could propagate from infected devices across the integrated spacecraft. For example, test equipment (i.e., transient cyber asset) is often brought in for testing elements of the spacecraft. Additionally, varying levels of physical security is in place which may be a reduction in physical security typically seen during development. The ATLO environment should be considered a viable attack vector and the appropriate/equivalent security controls from the primary development environment should be implemented during ATLO as well.
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-0001.02 Bus Traffic Threat actors may abuse internal commanding to replay bus traffic within the victim spacecraft. On-board resources within the spacecraft 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-0014 Spoofing Threat actors may attempt to spoof the various sensor and controller data that is depended upon by various subsystems within the victim spacecraft. Subsystems rely on this data to perform automated tasks, process gather data, and return important information to the ground controllers. By spoofing this information, threat actors could trigger automated tasks to fire when they are not needed to, potentially causing the spacecraft to behave erratically. Further, the data could be processed erroneously, causing ground controllers to receive incorrect telemetry or scientific data, threatening the spacecraft's reliability and integrity.
EX-0014.02 Bus Traffic Threat actors may attempt to target the main or secondary bus onboard the victim spacecraft and spoof their data. The spacecraft bus often directly processes and sends messages from the ground controllers to the various subsystems within the spacecraft and between the subsystems themselves. If a threat actor would target this system and spoof it internally, the subsystems would take the spoofed information as legitimate and process it as normal. This could lead to undesired effects taking place that could damage the spacecraft's subsystems, hosted payload, and critical data.
EX-0014.03 Sensor Data Threat actors may target sensor data on the space vehicle to achieve their attack objectives. Sensor data is typically inherently trusted by the space vehicle therefore an attractive target for a threat actor. Spoofing the sensor data could affect the calculations and disrupt portions of a control loop as well as create uncertainty within the mission thereby creating temporary denial of service conditions for the mission. Affecting the integrity of the sensor data can have varying impacts on the space vehicle depending on decisions being made by the space vehicle using the sensor data. For example, spoofing data related to attitude control could adversely impact the space vehicles ability to maintain orbit.
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.
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-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)
LM-0001 Hosted Payload Threat actors may use the hosted payload within the victim spacecraft in order to gain access to other subsystems. The hosted payload often has a need to gather and send data to the internal subsystems, depending on its purpose. Threat actors may be able to take advantage of this communication in order to laterally move to the other subsystems and have commands be processed.
LM-0002 Exploit Lack of Bus Segregation Threat actors may exploit victim spacecraft on-board flat architecture for lateral movement purposes. Depending on implementation decisions, spacecraft can have a completely flat architecture where remote terminals, sub-systems, payloads, etc. can all communicate on the same main bus without any segmentation, authentication, etc. Threat actors can leverage this poor design to send specially crafted data from one compromised devices or sub-system to laterally move to another area of the 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-0005 Virtualization Escape In virtualized environments, threat actors can use the open ports between the partitions to overcome the hypervisor's protection and damage another partition. Further, if the threat actor has compromised the payload, access to a critical partition can be gained through ports allowed by hypervisor.
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-0002.02 Electromagnetic Leakage Attacks Threat actors can leverage electromagnetic emanations to obtain sensitive information. The electromagnetic radiations attain importance when they are hardware generated emissions, especially emissions from the cryptographic module. Electromagnetic leakage attacks have been shown to be more successful than power analysis attacks on chicards. If proper protections are not in place on the spacecraft, the circuitry is exposed and hence leads to stronger emanations of EM radiations. If the circuitry is exposed, it provides an easier environment to study the electromagnetic emanations from each individual component.
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-0006 Modify Communications Configuration Threat actors can manipulate communications equipment, modifying the existing software, hardware, or the transponder configuration to exfiltrate data via unintentional channels the mission has no control over.
EXF-0006.01 Software Defined Radio Threat actors may target software defined radios due to their software nature to setup exfiltration channels. Since SDRs are programmable, when combined with supply chain or development environment attacks, SDRs provide a pathway to setup covert exfiltration channels for a threat actor.
EXF-0006.02 Transponder Threat actors may change the transponder configuration to exfiltrate data via radio access to an attacker-controlled asset.
EXF-0007 Compromised Ground System Threat actors may compromise target owned ground systems that can be used for future campaigns 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 an operation. Threat actors may utilize these systems for various tasks, including Execution and Exfiltration.
EXF-0008 Compromised Developer Site Threat actors may compromise development environments located within the ground system or a developer/partner site. This attack can take place in a number of different ways, including manipulation of source code, manipulating environment variables, or replacing compiled versions with a malicious one. This technique is usually performed before the target spacecraft is in orbit, with the hopes of adding malicious code to the actual FSW during the development process.
EXF-0009 Compromised Partner Site Threat actors may compromise access to partner sites that can be used for future campaigns or to perpetuate other techniques. These sites are typically configured for communications to the primary ground station(s) or in some cases the spacecraft itself. Unlike mission operated ground systems, partner sites may provide an easier target for threat actors depending on the company, roles and responsibilities, and interests of the third-party. 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.
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.