| name | AC-9(1)_unsuccessful-logons |
| description | Notify the user, upon successful logon, of the number of unsuccessful logon attempts since the last successful logon. |
| category | authorization |
| version | 5.2.0 |
| author | cyberstrike-official |
| tags | ["nist","sp800-53","rev5","ac-9-1","ac","enhancement"] |
| tech_stack | ["aws","azure","gcp","linux","windows"] |
| cwe_ids | ["CWE-284"] |
| chains_with | [] |
| prerequisites | ["AC-9"] |
| severity_boost | {} |
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
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
| Tool | Purpose | Usage |
|---|
| cloud-audit-mcp | Check IAM policies and access controls | cloud_audit_iam_policies |
| hackbrowser-mcp | Test web application access controls | browser_auth_test |
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
