SI-2

Control Statement

Supplemental Guidance

The need to remediate system flaws applies to all types of software and firmware. Organizations identify systems affected by software flaws, including potential vulnerabilities resulting from those flaws, and report this information to designated organizational personnel with information security and privacy responsibilities. Organizations consider establishing a controlled patching environment for mission-critical systems. Security-relevant updates include patches, service packs, and malicious code signatures. Organizations also address flaws discovered during assessments, continuous monitoring, incident response activities, and system error handling. By incorporating flaw remediation into configuration management processes, required remediation actions can be tracked and verified. Organization-defined time periods for updating security-relevant software and firmware may vary based on a variety of risk factors, including the security category of the system, the criticality of the update (i.e., severity of the vulnerability related to the discovered flaw), the organizational risk tolerance, the mission supported by the system, or the threat environment. Some types of flaw remediation may require more testing than other types. Organizations determine the type of testing needed for the specific type of flaw remediation activity under consideration and the types of changes that are to be configuration-managed. Flaw remediation testing addresses both effectiveness of addressing security issues and for potential side effects on functionality, system and system component performance and operations. When implementing remediation activities, organizations consider the order and timing of updates to validate correct execution within the system environment, and to support system and component availability needs (i.e., implementing a staggered deployment strategy). In some situations, organizations may determine that the testing of software or firmware updates is not necessary or practical, such as when implementing simple malicious code signature updates. In testing decisions, organizations consider whether security-relevant software or firmware updates are obtained from authorized sources with appropriate digital signatures. When implementing remediation activities, organizations consider the order and timing of updates to validate correct execution within the system environment, and to support system and component availability needs (i.e., implementing a staggered deployment strategy). Organizations verify that software and firmware updates come from authorized sources prior to downloading.

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