TOR-2018-02275 - A Need for Robust Space Vehicle Cybersecurity
High-Level Requirements
The Program shall specifically develop a defense-in-depth architecture for the spacecraft and document within applicable security documentation.
Low-Level Requirements
Requirement
Rationale/Additional Guidance/Notes
The [organization] shall protect the security plan from unauthorized disclosure and modification.{SV-MA-6}{AC-3,PL-2,PL-7}
The [organization] shall plan and coordinate security-related activities affecting the spacecraft with groups associated with systems from which the spacecraft is inheriting satisfaction of controls before conducting such activities in order to reduce the impact on other organizational entities.{SV-MA-6}{PL-2}
The [organization] shall document the spacecraft's security architecture, and how it is established within and is an integrated part of the Program's mission security architecture.{SV-MA-6}{SA-17}
The [organization] shall ensure that the allocated security safeguards operate in a coordinated and mutually reinforcing manner.{SV-MA-6}{CA-7(5),PL-7,PL-8(1),SA-8(19)}
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)}
Use threat modeling, attack surface analysis, and vulnerability analysis to inform the current development process using analysis from similar systems, components, or services where applicable. Reduce attack surface where possible based on threats.
Conduct a criticality analysis to identify mission critical functions, critical components, and data flows and reduce the vulnerability of such functions and components through secure system design. Focus supply chain protection on the most critical components/functions. Leverage other countermeasures like segmentation and least privilege to protect the critical components.
A distributed system uses a number of nodes, working together, to perform the same mission or functions as a single node. In a distributed constellation, the end user is not dependent on any single satellite but rather uses multiple satellites to derive a capability. A distributed constellation can complicate an adversary’s counterspace planning by presenting a larger number of targets that must be successfully attacked to achieve the same effects as targeting just one or two satellites in a less-distributed architecture. GPS is an example of a distributed constellation because the functioning of the system is not dependent on any single satellite or ground station; a user can use any four satellites within view to get a time and position fix.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Proliferated satellite constellations deploy a larger number of the same types of satellites to similar orbits to perform the same missions. While distribution relies on placing more satellites or payloads on orbit that work together to provide a complete capability, proliferation is simply building more systems (or maintaining more on-orbit spares) to increase the constellation size and overall capacity. Proliferation can be an expensive option if the systems being proliferated are individually expensive, although highly proliferated systems may reduce unit costs in production from the learning curve effect and economies of scale.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
In a diversified architecture, multiple systems contribute to the same mission using platforms and payloads that may be operating in different orbits or in different domains. For example, wideband communications to fixed and mobile users can be provided by the military’s WGS system, commercial SATCOM systems, airborne communication nodes, or terrestrial networks. The Chinese BeiDou system for positioning, navigation, and timing uses a diverse set of orbits, with satellites in geostationary orbit (GEO), highly inclined GEO, and medium Earth orbit (MEO). Diversification reduces the incentive for an adversary to attack any one of these systems because the impact on the overall mission will be muted since systems in other orbits or domains can be used to compensate for losses. Moreover, attacking space systems in diversified orbits may require different capabilities for each orbital regime, and the collateral damage from such attacks, such as orbital debris, could have a much broader impact politically and economically.*
*https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210225_Harrison_Defense_Space.pdf?N2KWelzCz3hE3AaUUptSGMprDtBlBSQG
Ensure spacecraft's operating system is scrutinized/whitelisted and has received adequate software assurance previously. The operating system should be analyzed for its attack surface and non-utilized features should be stripped from the operating system. Many real-time operating systems contain features that are not necessary for spacecraft operations and only increase the attack surface.
Ensure fault management system cannot be used against the spacecraft. Examples include: safe mode with crypto bypass, orbit correction maneuvers, affecting integrity of telemetry to cause action from ground, or some sort of proximity operation to cause spacecraft to go into safe mode. Understanding the safing procedures and ensuring they do not put the spacecraft in a more vulnerable state is key to building a resilient spacecraft.
Provide the capability to enter the spacecraft into a configuration-controlled and integrity-protected state representing a known, operational cyber-safe state (e.g., cyber-safe mode). Spacecraft should enter a cyber-safe mode when conditions that threaten the platform are detected. 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 software functions to pre-attack 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 equipment still available after a cyber-attack. The goal is for the spacecraft to resume full mission operations. If not possible, a reduced level of mission capability should be achieved. Cyber-safe mode software/configuration should be stored onboard the spacecraft in memory with hardware-based controls and should not be modifiable.