AC-9(1)_unsuccessful-logons

AC-9(1) Unsuccessful Logons

Enhancement of: AC-9

High-Level Description

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

Information about the number of unsuccessful logon attempts since the last successful logon allows the user to recognize if the number of unsuccessful logon attempts is consistent with the user’s actual logon attempts.

What to Check

• Verify AC-9(1) Unsuccessful Logons is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for AC-9(1)
• Verify enhancement builds upon base control AC-9

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AC-9(1) 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

Notify the user, upon successful logon, of the number of unsuccessful logon attempts since the last successful logon.

Implementation Guidance

Information about the number of unsuccessful logon attempts since the last successful logon allows the user to recognize if the number of unsuccessful logon attempts is consistent with the user’s actual logon attempts.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - AC-9(1)
• 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 (none) reviewed