CWE List

Create prioritized list of software weakness classes (e.g., Common Weakness Enumerations), based on system-specific considerations, to be used during static code analysis for prioritization of static analysis results.

Best Segment for Countermeasure Deployment

Development Environment

NIST Rev5 Controls

D3FEND Techniques

D3FEND Artifacts

Digital Artifact

ISO 27001

ID: CM0016

NASA Best Practice Guide: MI-AUTH-01 | MI-AUTH-02 | MI-INTG-01 | MI-DCO-02

ESA Space Shield Mitigation: None

Created: 2022/10/19

Last Modified: 2023/11/29

Techniques Addressed by Countermeasure

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.
	.02	Software Supply Chain	Threat actors may manipulate software binaries and applications prior to the customer receiving them in order 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.
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.
	.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.
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.
	.01	Flight Software	Threat actors may abuse known or unknown flight software code flaws in order to further the attack campaign. Some FSW suites contain API functionality for operator interaction. Threat actors may seek to exploit these or abuse a vulnerability/misconfiguration to maliciously execute code or commands. In some cases, these code flaws can perpetuate throughout the victim spacecraft, allowing access to otherwise segmented subsystems.
	.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.
EX-0010		Malicious Code	Threat actors may rely on other tactics and techniques in order to execute malicious code on the victim spacecraft. This can be done via compromising the supply chain or development environment in some capacity or taking advantage of known commands. However, once malicious code has been uploaded to the victim spacecraft, the threat actor can then trigger the code to run via a specific command or wait for a legitimate user to trigger it accidently. The code itself can do a number of different things to the hosted payload, subsystems, or underlying OS.
	.01	Ransomware	Threat actors may encrypt spacecraft data to interrupt availability and usability. Threat actors can attempt to render stored data inaccessible by encrypting files or data and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key or to render data permanently inaccessible in cases where the key is not saved or transmitted.
	.02	Wiper Malware	Threat actors may deploy wiper malware, which is a type of malicious software designed to destroy data or render it unusable. Wiper malware can spread through various means, software vulnerabilities (CWE/CVE), or by exploiting weak or stolen credentials.
	.03	Rootkit	Rootkits are programs that hide the existence of malware by intercepting/hooking and modifying operating system API calls that supply system information. Rootkits or rootkit enabling functionality may reside at the flight software or kernel level in the operating system or lower, to include a hypervisor, Master Boot Record, or System Firmware.
	.04	Bootkit	Adversaries may use bootkits to persist on systems and evade detection. Bootkits reside at a layer below the operating system and may make it difficult to perform full remediation unless an organization suspects one was used and can act accordingly.
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.
	.02	Software	Threat actors may inject code to create their own backdoor to establish persistent access to the spacecraft. This may be done through modification of code throughout the software supply chain or through modification of the software-defined radio configuration (if applicable).

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-SP-1	Exploitation of software vulnerabilities (bugs); Unsecure code, logic errors, etc. in the FSW.
SV-SP-3	Introduction of malicious software such as a virus, worm, Distributed Denial-Of-Service (DDOS) agent, keylogger, rootkit, or Trojan Horse
SV-SP-6	Software reuse, COTS dependence, and standardization of onboard systems using building block approach with addition of open-source technology leads to supply chain threat

Low-Level Requirements

Requirement	Rationale/Additional Guidance/Notes
In coordination with [organization], the [organization] shall prioritize and remediate flaws identified during security testing/evaluation.{CA-2,CA-5,SA-11,SI-3,SI-3(10)}
The [organization] shall implement a verifiable flaw remediation process into the developmental and operational configuration management process.{SV-SP-1,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-2,CA-5,SA-3,SA-3(1),SA-11,SI-3,SI-3(10)}	The verifiable process should also include a cross reference to mission objectives and impact statements. Understanding the flaws discovered and how they correlate to mission objectives will aid in prioritization.
The [organization] shall maintain evidence of the execution of the security assessment plan and the results of the security testing/evaluation.{SV-SP-1,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-2,CA-8,SA-11}
The [organization] shall create and implement a security assessment plan that includes: (1) The types of analyses, testing, evaluation, and reviews of all software and firmware components; (2) The degree of rigor to be applied to include abuse cases and/or penetration testing; and (3) The types of artifacts produced during those processes.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-2,CA-8,SA-11,SA-11(5)}	The security assessment plan should include evaluation of mission objectives in relation to the security of the mission. Assessments should not only be control based but also functional based to ensure mission is resilient against failures of controls.
The [organization] shall determine the vulnerabilities/weaknesses that require remediation, and coordinate the timeline for that remediation, in accordance with the analysis of the vulnerability scan report, the mission assessment of risk, and mission needs.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{CA-5,CM-3,RA-5,RA-7,SI-3,SI-3(10)}
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] shall perform software component analysis (a.k.a.origin analysis) for developed or acquired software.{CM-10,CM-10(1),RA-3(1),RA-5,SA-15(7),SI-3,SI-3(10),SR-4(4)}
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 share information obtained from the vulnerability scanning process and security control assessments with [Program-defined personnel or roles] to help eliminate similar vulnerabilities in other systems (i.e., systemic weaknesses or deficiencies).{SV-SP-1}{RA-5}
The [organization] shall ensure that the vulnerability scanning tools (e.g., static analysis and/or component analysis tools) used include the capability to readily update the list of potential information system vulnerabilities to be scanned.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,RA-5(1),RA-5(3),SI-3}
The [organization] shall perform vulnerability analysis and risk assessment of all systems and software.{SV-SP-1,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,RA-5(3),SA-15(7),SI-3}
The [organization] shall ensure that vulnerability scanning tools and techniques are employed that facilitate interoperability among tools and automate parts of the vulnerability management process by using standards for: (1) Enumerating platforms, custom software flaws, and improper configurations; (2) Formatting checklists and test procedures; and (3) Measuring vulnerability impact.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,RA-5(3),SI-3}	Component/Origin scanning looks for open-source libraries/software that may be included into the baseline and looks for known vulnerabilities and open-source license violations.
The [organization] shall perform static binary analysis of all firmware that is utilized on the spacecraft.{SV-SP-7,SV-SP-11}{RA-5,SA-10,SA-11,SI-7(10)}	Many commercial products/parts are utilized within the system and should be analyzed for security weaknesses. Blindly accepting the firmware is free of weakness is unacceptable for high assurance missions. The intent is to not blindly accept firmware from unknown sources and assume it is secure. This is meant to apply to firmware the vendors are not developing internally. In-house developed firmware should be going through the vendor's own testing program and have high assurance it is secure. When utilizing firmware from other sources, "expecting" does not meet this requirement. Each supplier needs to provide evidence to support that claim that their firmware they are getting is genuine and secure.
The [organization] shall perform static source code analysis for all available source code looking for [[organization]-defined Top CWE List] weaknesses using complimentary set of static code analysis tools (i.e.more than one).{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,SA-11(1),SA-15(7)}
The [organization] shall analyze vulnerability/weakness scan reports and results from security control assessments.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{RA-5,SI-3}
The [organization] shall correct flaws identified during security testing/evaluation.{SV-SP-1,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-11}	Flaws that impact the mission objectives should be prioritized.
The [organization] shall perform [Selection (one or more): unit; integration; system; regression] testing/evaluation at [Program-defined depth and coverage].{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-11}	The depth needs to include functional testing as well as negative/abuse testing.
The [organization] shall create prioritized list of software weakness classes (e.g., Common Weakness Enumerations) to be used during static code analysis for prioritization of static analysis results.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-11(1),SA-15(7)}	The prioritized list of CWEs should be created considering operational environment, attack surface, etc. Results from the threat modeling and attack surface analysis should be used as inputs into the CWE prioritization process. There is also a CWSS (https://cwe.mitre.org/cwss/cwss_v1.0.1.html) process that can be used to prioritize CWEs. The prioritized list of CWEs can help with tools selection as well as you select tools based on their ability to detect certain high priority CWEs.
The [organization] shall have automated means to evaluate adherence to coding standards.{SV-SP-1,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-15,SA-15(7),RA-5}	Manual review cannot scale across the code base; you must have a way to scale in order to confirm your coding standards are being met. The intent is for automated means to ensure code adheres to a coding standard.
The [organization] shall perform component analysis (a.k.a.origin analysis) for developed or acquired software.{SV-SP-1,SV-SP-2,SV-SP-3,SV-SP-6,SV-SP-7,SV-SP-9,SV-SP-11}{SA-15(7),RA-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.