Nm Leyline Supply Chain Advisory

Night Market Skill — ported from claude-night-market/leyline. For the full experience with agents, hooks, and commands, install the Claude Code plugin.

Overview#

Supply chain attacks bypass traditional code review by compromising upstream dependencies. This skill provides patterns for detecting, preventing, and responding to compromised packages in Python ecosystems.

When To Use#

• After a supply chain advisory is published
• When auditing dependencies for a new or existing project
• During incident response for a suspected compromise
• When adding the SessionStart hook to a project

When NOT To Use#

• General CVE triage unrelated to dependency supply chain
• Application-level vulnerability scanning (use a SAST tool)
• License compliance audits (different concern)

Known-Bad Versions Blocklist#

The blocklist is at ${CLAUDE_SKILL_DIR}/known-bad-versions.json. It is consumed by:

1. SessionStart hook — warns per-session when compromised versions detected
2. make supply-chain-scan — CI/local scanning target
3. This skill — manual audit guidance

Blocklist Format#

json

{
  "package_name": [{
    "versions": ["x.y.z"],
    "date": "YYYY-MM-DD",
    "description": "What the attack did",
    "indicators": ["files or patterns to search for"],
    "source": "advisory URL",
    "severity": "critical|high|medium"
  }]
}

Adding a New Entry#

1. Add the entry to ${CLAUDE_SKILL_DIR}/known-bad-versions.json
2. Add version exclusions ( !=x.y.z) to affected pyproject.toml files
3. Document in docs/dependency-audit.md under Supply Chain Incidents
4. Run make supply-chain-scan to verify detection works

Quick Scan Commands#

Check all lockfiles on machine for known-bad versions#

bash

# Scan uv.lock files for a specific compromised version
grep -r "package_name.*version" --include="uv.lock" /path/to/projects

# Search for malicious artifacts
find /path/to/projects -name "suspicious_file.pth" 2>/dev/null

# Check installed versions in virtualenvs
find /path/to/projects -path "*/.venv/lib/*/PACKAGE*/METADATA" \
  -exec grep "^Version:" {} +

Verify lockfile hash integrity#

uv.lock includes SHA256 hashes for every package. If a package is re-published with different content under the same version, uv sync will fail with a hash mismatch. This is your strongest automatic defense.

Defense Layers#

LayerToolCatchesLockfile hashesuv.lock SHA256Tampered re-published versionsVersion exclusionspyproject.toml !=Known-bad versions on fresh resolveSessionStart hooksanctum hookPer-session warning for compromised depsCI scanningOSV, SafetyCVE database, and advisory matchingArtifact scanningmake supply-chain-scanMalicious files (.pth, scripts)

Limitations#

• Zero-day supply chain attacks have no prior advisory — lockfile hashes are the only automatic defense during the attack window
• Safety/CVE databases lag behind real-world compromises
• OSV provides broader coverage but is still reactive