Supply Chain Incident Response

Supply Chain Incident Response

Threat Model

Scanner-clean post-advisory does not mean clean during the exposure window. The 4-point check (lockfile, CI cache, secrets, persistence) is the irreducible work to determine what the bad version actually touched.

Triage Flow

Run in order. Each step has a verifying command and a concrete output. Do not advance until the previous step's output is captured.

Step 1 — Parse the advisory

# If GHSA: fetch and parse
gh api /advisories/<id> --jq '{summary, affected: .vulnerabilities | map({pkg: .package.name, range: .vulnerable_version_range})}'

# If CVE: lookup on GitHub
gh api search/issues --raw-field q="<cve-id>" --jq '.items[].html_url' | head -5

Output: affected package names, version ranges, and exposure window (publish time of bad version → yank time, or now if unyanked).

Step 2 — Determine when this project resolved the bad version

# Show lockfile history for the affected package
git log --oneline --follow -p -- <lockfile> | grep -B 2 -E "<affected-package>"

Output: commits and timestamps showing when this project pinned the bad version. Cross-reference against the exposure window from Step 1 to confirm overlap. If no overlap → PASS, stop here, document.

Scope determination (which lockfiles even mention the package) is the Lockfile item in the 4-Point Check below — go there next.

The 4-Point Check

For each item: run the command, record PASS / EXPOSED / UNKNOWN with evidence for the incident report.

1. Lockfile — did any of our lockfiles resolve to the affected version?

   # Search every ecosystem's lockfile + manifest in one pass
   for pkg in <pkg1> <pkg2>; do
     git grep -nE "\"$pkg\"|^$pkg\\s|^$pkg==" -- '**/lock*' 'pyproject.toml' 'package.json' 'pixi.toml' 'Cargo.toml' 'go.mod'
   done
   

2. CI cache — did any workflow cache contain a build that used the affected version during the exposure window?

   gh actions cache list --sort created --order desc --json key,createdAt | jq '.[] | select(.createdAt > "<exposure-start>")'
   

3. Secrets — what secrets were in scope when the bad version executed?

   gh secret list && grep -rE 'env:|secrets\.' .github/workflows/
   

4. Persistence — did the bad version leave any artifact that survives?

   # Python .pth
   find $(python -c "import site; print(site.getsitepackages()[0])" 2>/dev/null) -name "*.pth" 2>/dev/null
   # npm bin/
   find node_modules/.bin -type f -newer <date>
   

Every result feeds the incident report's 4-Point Check Results table.

Phases

Containment

Pin a known-good version in the lockfile. Invalidate every CI cache built during the exposure window (gh actions cache delete <key>). Disable any workflow that ran the affected version until eradication is complete (gh workflow disable <file>). Done when: every lockfile pin is updated and every cached artifact from the window is purged.

Eradication

Rotate every secret enumerated in the 4-point check using references/secret-rotation.md. Hunt persistence artifacts using the appropriate runbook: references/runbook-account-takeover.md for npm/PyPI maintainer takeover, references/runbook-tag-hijack.md for GitHub Action tag hijack. Done when: every in-scope secret has a new value AND every persistence artifact is removed.

Recovery

Rebuild the project from the clean lockfile with no caches (gh workflow run <release> --field skip-cache=true). Verify the rebuilt artifacts' provenance using the supply-chain-sbom-provenance skill if SBOM/attestations are configured. Done when: rebuilt artifact matches expected provenance and tests pass.

Post-incident

Fill assets/incident-report-template.md. Update posture using the supply-chain-threat-awareness skill. File a GHSA at https://github.com/<owner>/<repo>/security/advisories/new if this project itself shipped an affected version. Done when: incident report is complete and prevention items are linked to skills/commands.

Choose Your Runbook

• Maintainer account takeover (Shai-Hulud-style npm/PyPI compromise) → references/runbook-account-takeover.md
• Release tag hijacking (TeamPCP-style GitHub Action mutation) → references/runbook-tag-hijack.md
• Secret rotation (every incident, regardless of vector) → references/secret-rotation.md

Output: Incident Report

Produce a filled copy of assets/incident-report-template.md. Every section must be populated — leave none as placeholder. Each 4-point check item gets PASS / EXPOSED / UNKNOWN with evidence (file:line, run URL, cache key, or "absent") and a follow-up action. Every Prevention Item must link to a skill or /command in this plugin.