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SA-8(11) - Security and Privacy Engineering Principles | Inverse Modification Threshold

Implement the security design principle of inverse modification threshold in [Assignment: organization-defined systems or system components].


Informational References

ISO 27001

ID: SA-8(11)
Enhancement of : SA-8

Countermeasures Covered by Control

ID Name Description D3FEND
CM0024 Anti-counterfeit Hardware Develop and implement anti-counterfeit policy and procedures designed to detect and prevent counterfeit components from entering the information system, including tamper resistance and protection against the introduction of malicious code or hardware.  D3-AI D3-SWI D3-HCI D3-FEMC D3-DLIC D3-FV
CM0027 ASIC/FPGA Manufacturing Application-Specific Integrated Circuit (ASIC) / Field Programmable Gate Arrays should be developed by accredited trusted foundries to limit potential hardware-based trojan injections. D3-OAM D3-ODM D3-AM D3-FV D3-SFV
CM0028 Tamper Protection Perform physical inspection of hardware to look for potential tampering. Leverage tamper proof protection where possible when shipping/receiving equipment. D3-PH D3-AH D3-RFS D3-FV

Space Threats Tagged by Control

ID Description

Sample Requirements

Requirement Rationale/Additional Guidance/Notes
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] 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 [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 [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] boot firmware must validate the boot loader, boot configuration file, and operating system image, in that order, against their respective signatures.{SV-IT-3}{SA-8(10),SA-8(11),SA-8(12),SI-7(9),SI-7(10)} A signature is ~770 bits long. No requirement is imposed on the storage location of signatures.
The [spacecraft] boot firmware must verify a trust chain that extends through the hardware root of trust, boot loader, boot configuration file, and operating system image, in that order.{SV-IT-3}{SA-8(10),SA-8(11),SA-8(12),SI-7(9),SI-7(10)} These three items were chosen because they’re intended to be static values (once properly set up) but are in volatile storage. Also, the Boot ROM can’t be modified, so there’s no reason to check a signature.
The [spacecraft] trusted boot/RoT computing module shall be implemented on radiation tolerant burn-in (non-programmable) equipment.{SA-8(10),SA-8(11),SA-8(12),SI-7(9),SI-7(10)}
The [spacecraft] trusted boot/RoT shall be a separate compute engine controlling the trusted computing platform cryptographic processor.{SA-8(10),SA-8(11),SA-8(12),SI-7(9),SI-7(10)}
The [spacecraft] shall perform attestation at each stage of startup and ensure overall trusted boot regime (i.e., root of trust).{SV-IT-3}{SA-8(10),SA-8(11),SA-8(12),SI-7(9),SI-7(10),SI-7(17)} It is important for the computing module to be able to access a set of functions and commands that it trusts; that is, that it knows to be true. This concept is referred to as root of trust (RoT) and should be included in the spacecraft design. With RoT, a device can always be trusted to operate as expected. RoT functions, such as verifying the device’s own code and configuration, must be implemented in secure hardware (i.e., field programmable gate arrays). By checking the security of each stage of power-up, RoT devices form the first link in a chain of trust that protects the spacecraft

Related SPARTA Techniques and Sub-Techniques

ID Name Description
IA-0001 Compromise Supply Chain Threat actors may manipulate or compromise products or product delivery mechanisms before the customer receives them in order to achieve data or system compromise.
IA-0001.03 Hardware Supply Chain Threat actors may 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. A spacecraft component can also be damaged if a specific HW component, built to fail after a specific period, or counterfeit with a low reliability, breaks out.
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-0004.02 Receiver Threat actors may target the backup/secondary receiver on the spacecraft as a method to inject malicious communications into the mission. The secondary receivers may come from different supply chains than the primary which could have different level of security and weaknesses. Similar to the ground station, the communication through the secondary receiver could be forced or happening naturally.
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-0011 Auxiliary Device Compromise Threat actors may exploit the auxiliary/peripheral devices that get plugged into spacecrafts. It is no longer atypical to see spacecrafts, 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 spacecrafts by copying the malicious code to auxiliary/peripheral devices and taking advantage of logic on the spacecraft 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-0004 Compromise Boot Memory Threat actors may manipulate boot memory in order to execute malicious code, bypass internal processes, or DoS the system. This technique can be used to perform other tactics such as Defense Evasion.
EX-0005 Exploit Hardware/Firmware Corruption Threat actors can target the underlying hardware and/or firmware using various TTPs that will be dependent on the specific hardware/firmware. Typically, software tools (e.g., antivirus, antimalware, intrusion detection) can protect a system from threat actors attempting to take advantage of those vulnerabilities to inject malicious code. However, there exist security gaps that cannot be closed by the above-mentioned software tools since they are not stationed on software applications, drivers or the operating system but rather on the hardware itself. Hardware components, like memory modules and caches, can be exploited under specific circumstances thus enabling backdoor access to potential threat actors. In addition to hardware, the firmware itself which often is thought to be software in its own right also provides an attack surface for threat actors. Firmware is programming that's written to a hardware device's non-volatile memory where the content is saved when a hardware device is turned off or loses its external power source. Firmware is written directly onto a piece of hardware during manufacturing and it is used to run on the device and can be thought of as the software that enables hardware to run. In the spacecraft context, firmware and field programmable gate array (FPGA)/application-specific integrated circuit (ASIC) logic/code is considered equivalent to firmware.
EX-0005.01 Design Flaws Threat actors may target design features/flaws with the hardware design to their advantage to cause the desired impact. Threat actors may utilize the inherent design of the hardware (e.g. hardware timers, hardware interrupts, memory cells), which is intended to provide reliability, to their advantage to degrade other aspects like availability. Additionally, field programmable gate array (FPGA)/application-specific integrated circuit (ASIC) logic can be exploited just like software code can be exploited. There could be logic/design flaws embedded in the hardware (i.e., FPGA/ASIC) which may be exploitable by a threat actor.
PER-0001 Memory Compromise Threat actors may manipulate memory (boot, RAM, etc.) in order for their malicious code and/or commands to remain on the victim spacecraft. The spacecraft may have mechanisms that allow for the automatic running of programs on system reboot, entering or returning to/from safe mode, or during specific events. Threat actors may target these specific memory locations in order to store their malicious code or file, ensuring that the attack remains on the system even after a reset.
PER-0002 Backdoor Threat actors may find and target various backdoors, or inject their own, within the victim spacecraft in the hopes of maintaining their attack.
PER-0002.01 Hardware Threat actors may find and target various hardware backdoors within the victim spacecraft in the hopes of maintaining their attack. Once in orbit, mitigating the risk of various hardware backdoors becomes increasingly difficult for ground controllers. By targeting these specific vulnerabilities, threat actors are more likely to remain persistent on the victim spacecraft and perpetuate further attacks.
PER-0004 Replace Cryptographic Keys Threat actors may attempt to fully replace the cryptographic keys on the spacecraft which could lockout the mission operators and enable the threat actor's communication channel. Once the encryption key is changed on the spacecraft, the spacecraft is rendered inoperable from the operators perspective as they have lost commanding access. Threat actors may exploit weaknesses in the key management strategy. For example, the threat actor may exploit the over-the-air rekeying procedures to inject their own cryptographic keys.
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.
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.