AC-10_concurrent-session-control

AC-10 Concurrent Session Control

High-Level Description

Family: Access Control (AC) Framework: NIST SP 800-53 Rev 5

Organizations may define the maximum number of concurrent sessions for system accounts globally, by account type, by account, or any combination thereof. For example, organizations may limit the number of concurrent sessions for system administrators or other individuals working in particularly sensitive domains or mission-critical applications. Concurrent session control addresses concurrent sessions for system accounts. It does not, however, address concurrent sessions by single users via multiple system accounts.

What to Check

• Verify AC-10 Concurrent Session Control is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for AC-10

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AC-10 implementation details. Verify the organization has documented how this control is satisfied.

Step 2: Validate Implementation

# For cloud environments, use cloud-audit-mcp tools
# For on-premises, review system configurations directly

# Example: Check if account management policies exist
grep -r "account.management\|access.control" /etc/security/ 2>/dev/null

Step 3: Test Operating Effectiveness

Verify the control is actively functioning, not just documented. Check logs, configurations, and operational evidence.

Tools

Remediation Guide

Control Statement

Limit the number of concurrent sessions for each [organization-defined] to [organization-defined].

Implementation Guidance

Organizations may define the maximum number of concurrent sessions for system accounts globally, by account type, by account, or any combination thereof. For example, organizations may limit the number of concurrent sessions for system administrators or other individuals working in particularly sensitive domains or mission-critical applications. Concurrent session control addresses concurrent sessions for system accounts. It does not, however, address concurrent sessions by single users via multiple system accounts.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - AC-10
• NIST SP 800-53A Rev 5 (Assessment Procedures)
• NIST SP 800-53 Rev 5 Full Catalog

Checklist

• Control documented in SSP
• Implementation evidence collected
• Operating effectiveness validated
• Continuous monitoring in place
• Related controls (SC-23) reviewed