GitHub Actions Cache Hardening Audit

Use this skill to statically audit .github/workflows/*.yml for risky cache patterns that can cause cache poisoning, stale cache churn, or secret leakage.

What this skill checks

• actions/cache usage on untrusted triggers (pull_request_target)
• Cache keys that do not use hashFiles(...)
• Overly broad restore-keys prefixes
• Sensitive paths accidentally included in cache paths (.aws, .ssh, .npmrc, .git)
• Floating cache action refs (@main, @master)

Inputs

Optional:

• WORKFLOW_GLOB (default: .github/workflows/*.y*ml)
• TOP_N (default: 20)
• OUTPUT_FORMAT (text or json, default: text)
• WARN_SCORE (default: 3)
• CRITICAL_SCORE (default: 6)
• WORKFLOW_FILE_MATCH (regex, optional)
• WORKFLOW_FILE_EXCLUDE (regex, optional)
• FAIL_ON_CRITICAL (0 or 1, default: 0)

Run

Text report:

WORKFLOW_GLOB='.github/workflows/*.yml' \
bash skills/github-actions-cache-hardening-audit/scripts/cache-hardening-audit.sh

JSON output + fail gate:

WORKFLOW_GLOB='.github/workflows/*.yml' \
OUTPUT_FORMAT=json \
FAIL_ON_CRITICAL=1 \
bash skills/github-actions-cache-hardening-audit/scripts/cache-hardening-audit.sh

Run against bundled fixtures:

WORKFLOW_GLOB='skills/github-actions-cache-hardening-audit/fixtures/*.yml' \
bash skills/github-actions-cache-hardening-audit/scripts/cache-hardening-audit.sh

Output contract

• Exit 0 by default (report mode)
• Exit 1 when FAIL_ON_CRITICAL=1 and at least one critical workflow is detected
• Text mode prints a summary and top flagged workflows
• JSON mode emits summary, flagged_workflows, and critical_workflows