AC-9(1)_unsuccessful-logons
DevOps & SecurityAC-9(1)_unsuccessful-logons is an Agent Skill for devops & security published in the CyberStrikeus/CyberStrike repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.
Notify the user, upon successful logon, of the number of unsuccessful logon attempts since the last successful logon.
How to use this skill
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- Open your project in Codex.
- Copy and paste the prompt below.
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Inspect the Agent Skill at https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/NIST/SP800-53_rev5/AC_access-control/AC-9(1)_unsuccessful-logons/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/ac-9-1-unsuccessful-logons, but wait for my approval before writing files or running scripts.
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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
| 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
| Finding | Severity | Impact |
|---|---|---|
| AC-9(1) Unsuccessful Logons not implemented | High | Access Control |
| AC-9(1) partially implemented | Medium | Incomplete Access Control |
CWE Categories
| CWE ID | Title |
|---|---|
| CWE-284 | Improper Access Control |
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