Fault Injection Redundancy

To counter fault analysis attacks, it is recommended to use redundancy to catch injected faults. For certain critical functions that need protected against fault-based side channel attacks, it is recommended to deploy multiple implementations of the same function. Given an input, the spacecraft can process it using the various implementations and compare the outputs. A selection module could be incorporated to decide the valid output. Although sensor nodes have limited resources, critical regions usually comprise the crypto functions, which must be secured.

Sources

Best Segment for Countermeasure Deployment

  • Space Segment

NIST Rev5 Controls

D3FEND

ISO 27001

ID: CM0051
D3FEND Artifacts: 
Created: 2022/10/19
Last Modified: 2022/10/19

Techniques Addressed by Countermeasure

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ID Name Description
EX-0015 Side-Channel Attack Threat actors may use a side-channel attack attempts to gather information or influence the program execution of a system by measuring or exploiting indirect effects of the SV. Side-Channel attacks can be active or passive. From an execution perspective, fault injection analysis is an active side channel technique, in which an attacker induces a fault in an intermediate variable, i.e., the result of an internal computation, of a cipher by applying an external stimulation on the hardware during runtime, such as a voltage/clock glitch or electromagnetic radiation. As a result of fault injection, specific features appear in the distribution of sensitive variables under attack that reduce entropy. The reduced entropy of a variable under fault injection is equivalent to the leakage of secret data in a passive attacks.

Space Threats Addressed by Countermeasure

ID Description

Low-Level Requirements

Requirement Rationale/Additional Guidance/Notes
The [organization] shall produce a plan for the continuous monitoring of security control effectiveness.{SA-4(8),CP-4(5),PM-31}
The [organization] shall coordinate penetration testing on mission critical spacecraft components (hardware and/or software).{SV-MA-4}{CA-8,CA-8(1),CP-4(5)} Not all defects (i.e., buffer overflows, race conditions, and memory leaks) can be discovered statically and require execution of the system. This is where space-centric cyber testbeds (i.e., cyber ranges) are imperative as they provide an environment to maliciously attack components in a controlled environment to discover these undesirable conditions. Technology has improved to where digital twins for spacecraft are achievable, which provides an avenue for cyber testing that was often not performed due to perceived risk to the flight hardware.
The [organization] shall establish robust procedures and technical methods to perform testing to include adversarial testing (i.e.abuse cases) of the platform hardware and software.{CA-8,CP-4(5),RA-5,RA-5(1),RA-5(2),SA-3,SA-4(3),SA-11,SA-11(1),SA-11(2),SA-11(5),SA-11(7),SA-11(8),SA-15(7)}
The [organization] defines the security safeguards to be employed to protect the availability of system resources.{CP-2(2),SC-6,SI-13,SI-17}
The [spacecraft] 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.{AC-3(2),SI-3(8),SI-13}
The [spacecraft] shall integrate cyber related detection and responses with existing fault management capabilities to ensure tight integration between traditional fault management and cyber intrusion detection and prevention.{SV-DCO-1}{AU-6(4),IR-4,IR-4(1),RA-10,SA-8(21),SA-8(26),SC-3(4),SI-3,SI-3(10),SI-4(7),SI-4(13),SI-4(16),SI-4(24),SI-4(25),SI-7(7),SI-13} The onboard IPS system should be integrated into the existing onboard spacecraft fault management system (FMS) because the FMS has its own fault detection and response system built in. SV corrective behavior is usually limited to automated fault responses and ground commanded recovery actions. Intrusion prevention and response methods will inform resilient cybersecurity design. These methods enable detected threat activity to trigger defensive responses and resilient SV recovery.
The [spacecraft] shall have fault-tolerant authoritative time sourcing for the platform's clock.{SV-IT-1}{AU-8(2),SC-45,SC-45(1),SC-45(2),SI-13} * Adopt voting schemes (triple modular redundancy) that include inputs from backup sources. Consider providing a second reference frame against which short-term changes or interferences can be compared. * Atomic clocks, crystal oscillators and/or GPS receivers are often used as time sources. GPS should not be used as the only source due to spoofing/jamming concerns.
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 [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 [spacecraft] shall recover to a known cyber-safe state when an anomaly is detected.{IR-4,IR-4(1),SA-8(16),SA-8(19),SA-8(21),SA-8(24),SI-3,SI-4(7),SI-10(6),SI-13,SI-17}
The [spacecraft] shall detect and recover from detected memory errors or transitions to a known cyber-safe state.{IR-4,IR-4(1),SA-8(16),SA-8(24),SI-3,SI-4(7),SI-10(6),SI-13,SI-17}
The [spacecraft] shall operate securely in off-nominal power conditions, including loss of power and spurious power transients.{PE-11,PE-11(1),SA-8(16),SA-8(19),SI-13,SI-17}
The [spacecraft] 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.{SC-16(2),SI-4(13),SI-4(25),SI-10,SI-10(6),SI-13}
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 perform prerequisite checks for the execution of hazardous commands.{SI-10,SI-10(6),SI-13}
The [spacecraft] shall validate a functionally independent parameter prior to the issuance of any sequence that could remove an inhibit, or perform a hazardous action.{SI-10(3),SI-10(6),SI-13}
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}