Least Privilege

Employ the principle of least privilege, allowing only authorized processes which are necessary to accomplish assigned tasks in accordance with system functions. Ideally maintain a separate execution domain for each executing process.

Best Segment for Countermeasure Deployment

  • Space Segment

NIST Rev5 Controls

D3FEND

ISO 27001

ID: CM0039
D3FEND Artifacts: 
Created: 2022/10/19
Last Modified: 2022/12/08

Techniques Addressed by Countermeasure

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ID Name Description
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.
.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.
.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-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.
.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.
.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.
.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.
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.
.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-0009 Exploit Code Flaws Threats actors may identify and exploit flaws or weaknesses within the software running on-board the target spacecraft. These attacks may be extremely targeted and tailored to specific coding errors introduced as a result of poor coding practices or they may target known issues in the commercial software components.
.02 Operating System Threat actors may exploit flaws in the operating system code, which controls the storage, memory management, provides resources to the FSW, and controls the bus. There has been a trend where some modern spacecraft are running Unix-based operating systems and establishing SSH connections for communications between the ground and spacecraft. Threat actors may seek to gain access to command line interfaces & shell environments in these instances. Additionally, most operating systems, including real-time operating systems, include API functionality for operator interaction. Threat actors may seek to exploit these or abuse a vulnerability/misconfiguration to maliciously execute code or commands.
.03 Known Vulnerability (COTS/FOSS) Threat actors may utilize knowledge of the spacecraft software composition to enumerate and exploit known flaws or vulnerabilities in the commercial or open source software running on-board the target spacecraft.
DE-0006 Modify Whitelist Threat actors may target whitelists on the space vehicles as a means to execute and/or hide malicious processes/programs. Whitelisting is a common technique used on traditional IT systems but has also been used on space vehicles. Whitelisting is used to prevent execution of unknown or potentially malicious software. However, this technique can be bypassed if not implemented correctly but threat actors may also simply attempt to modify the whitelist outright to ensure their malicious software will operate on the space vehicle that utilizes whitelisting.
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.
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.

Space Threats Addressed by Countermeasure

ID Description
SV-MA-3 Attacks on critical software subsystems   Attitude Determination and Control (AD&C) subsystem determines and controls the orientation of the satellite. Any cyberattack that could disrupt some portion of the control loop - sensor data, computation of control commands, and receipt of the commands would impact operations   Telemetry, Tracking and Commanding (TT&C) subsystem provides interface between satellite and ground system. Computations occur within the RF portion of the TT&C subsystem, presenting cyberattack vector   Command and Data Handling (C&DH) subsystem is the brains of the satellite. It interfaces with other subsystems, the payload, and the ground. It receives, validate, decodes, and sends commands to other subsystems, and it receives, processes, formats, and routes data for both the ground and onboard computer. C&DH has the most cyber content and is likely the biggest target for cyberattack.   Electrical Power Subsystem (EPS) provides, stores, distributes, and controls power on the satellite. An attack on EPS could disrupt, damage, or destroy the satellite.  
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;  

Low-Level Requirements

Requirement Rationale/Additional Guidance/Notes
The [organization] shall develop and document program-specific access control policies for controlling information flow and leakage on-board the spacecraft.{AC-1,AC-3,AC-3(3),AC-3(4),AC-3(13)}
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 maintain a list of suppliers and potential suppliers used, and the products that they supply to include software.{SV-SP-3,SV-SP-4,SV-SP-11}{CM-10,PL-8(2),PM-30,SA-8(9),SA-8(11)} Ideally you have diversification with suppliers
The [organization] shall develop and implement anti-counterfeit policy and procedures designed to detect and prevent counterfeit components from entering the information system, including support tamper resistance and provide a level of protection against the introduction of malicious code or hardware.{SV-SP-3,SV-SP-4,SV-AV-7,SV-SP-11}{CM-3(8),CM-7(9),PM-30,SA-8(9),SA-8(11),SA-9,SA-10(3),SA-19,SC-51,SR-4(3),SR-4(4),SR-5(2),SR-11}
The [organization] shall prohibit the use of binary or machine-executable code from sources with limited or no warranty and without the provision of source code.{SV-SP-1,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CM-7(8)}
The [organization] prohibits the use of binary or machine-executable code from sources with limited or no warranty and without the provision of source code.{CM-7(8),CM-7(8),CM-10(1),SA-8(9),SA-8(11),SA-10(2),SI-3,SR-4(4)}
The [organization] shall conduct a criticality analysis to identify mission critical functions and critical components and reduce the vulnerability of such functions and components through secure system design.{SV-SP-3,SV-SP-4,SV-AV-7,SV-MA-4}{CP-2,CP-2(8),PL-7,PM-11,PM-30(1),RA-3(1),RA-9,SA-8(9),SA-8(11),SA-8(25),SA-12,SA-14,SA-15(3),SC-7(29),SR-1} During SCRM, criticality analysis will aid in determining supply chain risk. For mission critical functions/components, extra scrutiny must be applied to ensure supply chain is secured.
The [organization] shall conduct a supplier review prior to entering into a contractual agreement with a sub [organization] to acquire systems, system components, or system services.{PM-30,PM-30(1),RA-3(1),SA-8(9),SA-8(11),SA-9,SA-12(2),SR-5(2),SR-6}
The [organization] shall protect against supply chain threats to the system, system components, or system services by employing security safeguards as defined by NIST SP 800-161 Rev.1.{SV-SP-3,SV-SP-4,SV-AV-7,SV-SP-11}{PM-30,RA-3(1),SA-8(9),SA-8(11),SA-12,SI-3,SR-1} The chosen supply chain safeguards should demonstrably support a comprehensive, defense-in-breadth information security strategy. Safeguards should include protections for both hardware and software. Program should define their critical components (HW & SW) and identify the supply chain protections, approach/posture/process.
The [organization] shall ensure that all Electrical, Electronic, Electro-mechanical & Electro-optical (EEEE)  and mechanical piece parts procured from the Original Component Manufacturer (OCM) or their authorized distribution network.{SA-8(9),SA-8(11),SA-12,SA-12(1),SC-16(1),SR-1,SR-5}
The [organization] shall use a certified environment to develop, code and test executable software (firmware or bit-stream) that will be programmed into a one-time programmable FPGA or be programmed into non-volatile memory (NVRAM) that the FPGA executes.{SA-8(9),SA-8(11),SA-12,SA-12(1),SC-51,SI-7(10),SR-1,SR-5}
The [organization] shall ensure that all ASICs designed, developed, manufactured, packaged, and tested by suppliers with a Defense Microelectronics Activity (DMEA) Trust accreditation.{spacecraft-SP-5} {SA-8(9),SA-8(11),SA-12,SA-12(1),SR-1,SR-5}
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.
For FPGA pre-silicon artifacts that are developed, coded, and tested by a developer that is not accredited, the [organization] shall be subjected to a development environment and pre-silicon artifacts risk assessment by [organization]. Based on the results of the risk assessment, the [organization] may need to implement protective measures or other processes to ensure the integrity of the FPGA pre-silicon artifacts.{SV-SP-5}{SA-3,SA-3(1),SA-8(9),SA-8(11),SA-12,SA-12(1),SR-1,SR-5} DOD-I-5200.44 requires the following: 4.c.2 “Control the quality, configuration, and security of software, firmware, hardware, and systems throughout their lifecycles... Employ protections that manage risk in the supply chain… (e.g., integrated circuits, field-programmable gate arrays (FPGA), printed circuit boards) when they are identifiable (to the supplier) as having a DOD end-use. “ 4.e “In applicable systems, integrated circuit-related products and services shall be procured from a Trusted supplier accredited by the Defense Microelectronics Activity (DMEA) when they are custom-designed, custommanufactured, or tailored for a specific DOD military end use (generally referred to as application-specific integrated circuits (ASIC)). “ 1.g “In coordination with the DOD CIO, the Director, Defense Intelligence Agency (DIA), and the Heads of the DOD Components, develop a strategy for managing risk in the supply chain for integrated circuit-related products and services (e.g., FPGAs, printed circuit boards) that are identifiable to the supplier as specifically created or modified for DOD (e.g., military temperature range, radiation hardened).
Any EEEE or mechanical piece parts that cannot be procured from the OCM or their authorized distribution network shall be approved and the government program office notified to prevent and detect counterfeit and fraudulent parts and materials.{SV-SP-5}{SA-8(9),SA-8(11),SA-12,SA-12(1),SR-1,SR-5} The Program, working with the contractors, shall identify which ASICs/FPGAs perform or execute an integral part of mission critical functions and if the supplier is accredited “Trusted” by DMEA. If the contractor is not accredited by DMEA, then the Program may apply various of the below ASIC/FPGA assurance requirements to the contractor, and the Program may need to perform a risk assessment of the contractor’s design environment.
For ASICs that are designed, developed, manufactured, packaged, or tested by a supplier that is not DMEA accredited, the ASIC development shall undergo a threat/vulnerability risk assessment. Based on the results of the risk assessment, the [organization] may need to implement protective measures or other processes to ensure the integrity of the ASIC.{SV-SP-5}{SA-8(9),SA-8(11),SA-8(21),SA-12,SA-12(1),SR-1,SR-4(4),SR-5} DOD-I-5200.44 requires the following: 4.c.2 “Control the quality, configuration, and security of software, firmware, hardware, and systems throughout their lifecycles... Employ protections that manage risk in the supply chain… (e.g., integrated circuits, field-programmable gate arrays (FPGA), printed circuit boards) when they are identifiable (to the supplier) as having a DOD end-use. “ 4.e “In applicable systems, integrated circuit-related products and services shall be procured from a Trusted supplier accredited by the Defense Microelectronics Activity (DMEA) when they are custom-designed, custommanufactured, or tailored for a specific DOD military end use (generally referred to as application-specific integrated circuits (ASIC)). “ 1.g “In coordination with the DOD CIO, the Director, Defense Intelligence Agency (DIA), and the Heads of the DOD Components, develop a strategy for managing risk in the supply chain for integrated circuit-related products and services (e.g., FPGAs, printed circuit boards) that are identifiable to the supplier as specifically created or modified for DOD (e.g., military temperature range, radiation hardened).
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 enforce an attribute-based access control policy over subjects and objects as defined in AC-3(3).{AC-3(13)}
The [spacecraft] software subsystems shall provide non-identical methods, or functionally independent methods, for commanding a mission critical function when the software is the sole control of that function.{SV-MA-3,SV-AV-7}{AC-3(2)}
The [spacecraft] software subsystems shall provide two independent and unique command messages to deactivate a fault tolerant capability for a critical or catastrophic hazard.{SV-MA-3,SV-AV-7}{AC-3(2)}
The [spacecraft] shall provide two independent and unique command messages to deactivate a fault tolerant capability for a critical or catastrophic hazard.{AC-3(2),PE-10,SA-8(15)}
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)}
All [spacecraft] commands which have unrecoverable consequence must have dual authentication prior to command execution.{AU-9(5),IA-3,IA-4,IA-10,PE-3,PM-12,SA-8(15),SA-8(21),SC-16(2),SC-16(3),SI-3(8),SI-3(9),SI-4(13),SI-4(25),SI-7(12),SI-10(6),SI-13}
The [spacecraft] shall have a method to ensure the integrity of these commands and validate their authenticity before execution.{AU-9(5),IA-3,IA-4,IA-10,PE-3,PM-12,SA-8(15),SA-8(21),SC-16(2),SC-16(3),SI-3(8),SI-3(9),SI-4(13),SI-4(25),SI-7(12),SI-10(6),SI-13}
The [organization] shall document and design a security architecture using a defense-in-depth approach that allocates the [organization]s defined safeguards to the indicated locations and layers: [Examples include: operating system abstractions and hardware mechanisms to the separate processors in the platform, internal components, and the FSW].{SV-MA-6}{CA-9,PL-7,PL-8,PL-8(1),SA-8(3),SA-8(4),SA-8(7),SA-8(9),SA-8(11),SA-8(13),SA-8(19),SA-8(29),SA-8(30)}
The [spacecraft] shall perform an integrity check of software, firmware, and information at startup or during security-relevant events. {CM-3(5),SA-8(9),SA-8(11),SA-8(21),SI-3,SI-7(1),SI-7(10),SI-7(12),SI-7(17)}
The [spacecraft] shall be configured to provide only essential capabilities.{CM-6,CM-7,SA-8(2),SA-8(7),SA-8(13),SA-8(23),SA-8(26),SA-15(5)}
The [spacecraft] operating system, if COTS or FOSS, shall be selected from a [organization]-defined acceptance list.{SV-SP-7}{CM-7(8),CM-7(5)}
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 [organization] shall implement a security architecture and design that provides the required security functionality, allocates security controls among physical and logical components, and integrates individual security functions, mechanisms, and processes together to provide required security capabilities and a unified approach to protection.{SV-MA-6}{PL-7,SA-2,SA-8,SA-8(1),SA-8(2),SA-8(3),SA-8(4),SA-8(5),SA-8(6),SA-8(7),SA-8(9),SA-8(11),SA-8(13),SA-8(19),SA-8(29),SA-8(30),SC-32,SC-32(1)}
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 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 [spacecraft] software subsystems shall provide independent mission/cyber critical threads such that any one credible event will not corrupt another mission/cyber critical thread.{SV-MA-3,SV-AV-7}{SC-3}
The [spacecraft] shall provide independent mission/cyber critical threads such that any one credible event will not corrupt another mission/cyber critical thread.{SC-3,SC-32,SC-32(1),SI-3,SI-13}
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] software subsystems shall accept [Program defined hazardous] commands only when prerequisite checks are satisfied.{SV-MA-3,SV-AV-7}{SI-10}
The [spacecraft] software subsystems shall identify and reject commands received out-of-sequence when the out-of-sequence commands can cause a hazard/failure or degrade the control of a hazard or mission.{SV-MA-3,SV-AV-7}{SI-10}
The [spacecraft] software subsystems shall perform prerequisite checks for the execution of hazardous commands.{SV-MA-3,SV-AV-7}{SI-10}
The [spacecraft] software subsystems shall discriminate between valid and invalid input into the software and rejects invalid input.{SV-MA-3,SV-AV-7}{SI-10,SI-10(3)}
The [spacecraft] software subsystems shall properly handle spurious input and missing data.{SV-MA-3,SV-AV-7}{SI-10,SI-10(3)}
The [spacecraft] software subsystems shall validate a functionally independent parameter prior to the issuance of any sequence that could remove an inhibit or perform a hazardous action.{SV-MA-3,SV-AV-7}{SI-10(3)}
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] 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)}
The [spacecraft] shall have failure tolerance on sensors used by software to make mission-critical decisions.{SV-MA-3,SV-AV-7}{SI-13,SI-17}
The [spacecraft] software subsystems shall detect and recover/transition from detected memory errors to a known cyber-safe state.{SV-MA-3,SV-AV-7}{SI-17}
The [spacecraft] software subsystems shall initialize the spacecraft to a known safe state.{SV-MA-3,SV-AV-7}{SI-17}
The [spacecraft] software subsystems shall operate securely in off-nominal power conditions, including loss of power and spurious power transients.{SV-MA-3,SV-AV-7}{SI-17}
The [spacecraft] software subsystems shall perform an orderly, controlled system shutdown to a known cyber-safe state upon receipt of a termination command or condition.{SV-MA-3,SV-AV-7}{SI-17}
The [spacecraft] software subsystems shall recover to a known cyber-safe state when an anomaly is detected.{SV-MA-3,SV-AV-7}{SI-17}
The [spacecraft] software subsystems shall safely transition between all predefined, known states.{SV-MA-3,SV-AV-7}{SI-17}