Discussion:

Baseline configurations are documented, formally reviewed, and agreed-upon specifications for systems or configuration items within those systems. Baseline configurations serve as a basis for future builds, releases, and changes to systems. Baseline configurations include information about system components (e.g., standard software packages installed on workstations, notebook computers, servers, network components, or mobile devices; current version numbers and update and patch information on operating systems and applications; and configuration settings and parameters), network topology, and the logical placement of those components within the system architecture. Baseline configurations of systems also reflect the current enterprise architecture. Maintaining effective baseline configurations requires creating new baselines as organizational systems change over time. Baseline configuration maintenance includes reviewing and updating the baseline configuration when changes are made based on security risks and deviations from the established baseline configuration

Organizations can implement centralized system component inventories that include components from multiple organizational systems. In such situations, organizations ensure that the resulting inventories include system-specific information required for proper component accountability (e.g., system association, system owner). Information deemed necessary for effective accountability of system components includes hardware inventory specifications, software license information, software version numbers, component owners, and for networked components or devices, machine names and network addresses. Inventory specifications include manufacturer, device type, model, serial number, and physical location.

[SP 800-128] provides guidance on security-focused configuration management.

Determining Statements (NIST SP 800-171Ar2)

3.4.1[a] a baseline configuration is established.
3.4.1[b] the baseline configuration includes hardware, software, firmware, and
documentation.
3.4.1[c] the baseline configuration is maintained (reviewed and updated) throughout
the system development life cycle.
3.4.1[d] a system inventory is established.
3.4.1[e] the system inventory includes hardware, software, firmware, and
documentation.
3.4.1[f] the inventory is maintained (reviewed and updated) throughout the system
development life cycle.

Assessors are instructed to-

Examine: [SELECT FROM: Configuration management policy; procedures addressing the baseline configuration of the system; procedures addressing system inventory; system security plan; configuration management plan; system inventory records; inventory review and update records; enterprise architecture documentation; system design documentation; system architecture and configuration documentation; system configuration settings and associated documentation; change control records; system component installation records; system component removal records; other relevant documents or records].

Interview: [SELECT FROM: Personnel with configuration management responsibilities; personnel with responsibilities for establishing the system inventory; personnel with responsibilities for updating the system inventory; personnel with information security responsibilities; system or network administrators].

Test: [SELECT FROM: Organizational processes for managing baseline configurations; mechanisms supporting configuration control of the baseline configuration; organizational processes for developing and documenting an inventory of system components; organizational processes for updating inventory of system components; mechanisms supporting or implementing the system inventory; mechanisms implementing updating of the system inventory].