AC-12 AC · Access Control

Session Termination

LOW ✓ MODERATE ✓ HIGH
3 Enhancements 1 Overlay 3 Related Controls
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Requirements NIST SOURCE

Automatically terminate a user session after [conditions or trigger events].

Discussion (NIST Supplemental Guidance)

Session termination addresses the termination of user-initiated logical sessions (in contrast to SC-10 , which addresses the termination of network connections associated with communications sessions (i.e., network disconnect)). A logical session (for local, network, and remote access) is initiated whenever a user (or process acting on behalf of a user) accesses an organizational system. Such user sessions can be terminated without terminating network sessions. Session termination ends all processes associated with a user’s logical session except for those processes that are specifically created by the user (i.e., session owner) to continue after the session is terminated. Conditions or trigger events that require automatic termination of the session include organization-defined periods of user inactivity, targeted responses to certain types of incidents, or time-of-day restrictions on system use.

Enhancements NIST SOURCE

AC-12(1) User-initiated Logouts LOW MODERATE HIGH

Provide a logout capability for user-initiated communications sessions whenever authentication is used to gain access to [information resources].

Discussion

Information resources to which users gain access via authentication include local workstations, databases, and password-protected websites or web-based services.

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AC-12(2) Termination Message LOW MODERATE HIGH

Display an explicit logout message to users indicating the termination of authenticated communications sessions.

Discussion

Logout messages for web access can be displayed after authenticated sessions have been terminated. However, for certain types of sessions, including file transfer protocol (FTP) sessions, systems typically send logout messages as final messages prior to terminating sessions.

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AC-12(3) Timeout Warning Message LOW MODERATE HIGH

Display an explicit message to users indicating that the session will end in [time].

Discussion

To increase usability, notify users of pending session termination and prompt users to continue the session. The pending session termination time period is based on the parameters defined in the AC-12 base control.

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Implementation Guidance

Engineering Interpretation

Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.

No engineering interpretation has been authored for AC-12 yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.

Assessment

NIST SP 800-53A REV 5.2.0

Assessment Objectives

  1. conditions or trigger events requiring session disconnect are defined;
  2. a user session is automatically terminated after <AC-12_ODP conditions or trigger events>.

Examine

[SELECT FROM: Access control policy; procedures addressing session termination; system design documentation; system configuration settings and associated documentation; list of conditions or trigger events requiring session disconnect; system audit records; system security plan; other relevant documents or records].

Interview

[SELECT FROM: System/network administrators; organizational personnel with information security responsibilities; system developers].

Test

[SELECT FROM: Automated mechanisms implementing user session termination].

Overlays

OT/ICS Overlay SP 800-82r3

NIST SP 800-82r3 Appendix F, Table 22. Blank baseline means the control/control enhancement is not selected in that initial OT baseline.

LOW

Not applicable at this tier.

MODERATE

  • Base control: Included (matches standard baseline)

HIGH

  • Base control: Included (matches standard baseline)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for AC-12. This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.

Learn more about STIG/CCI integration →

Evidence

Potential Evidence — Derived

Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.

Policy

  • Access control policy
  • system security plan

Configuration

  • system design documentation
  • system configuration settings and associated documentation

Testing

  • Automated mechanisms implementing user session termination

Other Records

  • procedures addressing session termination
  • list of conditions or trigger events requiring session disconnect
  • system audit records
  • other relevant documents or records