Supply Chain Security

Supply-Chain Security Scanner

This skill turns the model into a dependency reviewer. Read the manifests, lockfiles, install scripts, and the dependency diff; walk the detection passes; report each supply-chain risk with a severity and a concrete fix. No tools to install, no package to run, no registry to phone — the analysis is the model reading what's on disk and in the diff.

A dependency is the one thing in your project you didn't write and didn't review, running with your full privileges. The defender's problem is that it looks legitimate: the largest npm compromise in history rode chalk and debug (2 billion weekly downloads) through a phished maintainer, and the Shai-Hulud worm backdoored ~800 packages by republishing them under stolen tokens. Popularity is not safety. The moment to catch this is when a dependency is added or changed — that is what this skill reviews.

Mental model

A new or changed dependency runs code from a stranger twice: once at install time (lifecycle scripts — on your laptop and your CI runner, before a single line is reviewed) and again at runtime (in your app, your users' browsers, your servers). Two questions decide whether it is safe:

• Identity — is this the package you meant, from who you think published it? Defeated by typosquatting (a misspelling of a popular name), slopsquatting (a plausible name an AI hallucinated and an attacker pre-registered), dependency / namespace confusion (an internal name claimed on a public registry), and maintainer account takeover (a trusted name, a stolen token).
• Behavior — does it do something a library of its stated purpose has no reason to do? Especially at install time. Defeated by malicious lifecycle scripts, obfuscated payloads, credential harvesting, exfiltration, persistence, and self-propagation.

The install-time hook is the crown jewel. It executes before any code review, on developer machines and CI runners, with full environment and token access — which is exactly why every major worm (Shai-Hulud, the nx s1ngularity attack, the June 2026 binding.gyp campaign) targets install time. Most land in preinstall / postinstall; the binding.gyp worm bypasses those hooks entirely by tricking node-gyp into running arbitrary shell during a fake native build. A package can be perfectly functional and still own your machine the instant you install it.

When you cannot confirm a package's identity, or cannot explain what its install script does, treat it as untrusted and flag it. The cost of a false positive is a held PR and a few minutes. The cost of a false negative is every credential on the machine and in CI — and your own packages republished as the next link in the worm. This asymmetry governs every judgment call below.

Scan procedure

Walk these passes in order. Pass 0 establishes what you're reviewing and what's new — don't skip it.

Pass 0: scope what you're reviewing

You can't assess a dependency without knowing the ecosystem and how much of it you can actually see.

• Identify the ecosystem and files. package.json + a lockfile (npm/pnpm/yarn), requirements.txt / pyproject.toml / poetry.lock / uv.lock (PyPI), go.mod + go.sum, Cargo.toml + Cargo.lock, Gemfile + Gemfile.lock, pom.xml / build.gradle, .csproj / packages.lock.json, composer.json + composer.lock. See references/ecosystems.md for where install hooks, pinning, integrity, and scoping live in each.
• Find what's new or changed. In a PR, the diff of the manifest and lockfile is the target — a freshly added package, a version bump, a new transitive entry, a new install script. Note for each: direct vs transitive, new package vs version change, and whether the install runs anywhere holding secrets (CI with publish tokens, a developer laptop with cloud creds).
• Note how much you can see. If the package source is on disk (node_modules/, vendored, an extracted tarball), you can read its install scripts and payload directly — do it. If you only have a name and version in a manifest, you are limited to identity and hygiene checks; say so, and recommend the confirmation commands in the closing section.

Pass 1: identity — is this the package you meant?

Before behavior, confirm the name resolves to who you think.

• Typosquatting. A name within a small edit or keyboard distance of a popular package: crossenv↔cross-env, reqeusts↔requests, lodahs↔lodash, electorn↔electron. Flag any dependency whose name is one transposition/omission/duplication away from a well-known package it is not.
• Slopsquatting (AI-hallucinated names). Roughly 1 in 5 package names suggested by LLMs don't exist, and the hallucinations repeat — so attackers pre-register the popular ones with malware. Be suspicious of plausible-but-unfamiliar "helper" names (flask-gpt-helper, auth-helper-pro, py-openai-utils, easy-requests). If a dependency was added on an AI's suggestion, confirm the real package exists under that exact name before installing — do not let a hallucinated import become an install.
• Dependency / namespace confusion. An unscoped name that looks internal (internal-, corp-, company-, a product codename) can be hijacked: an attacker publishes the same name publicly with a higher version and wins resolution. Also flag a scope that is almost the org's (@acme-corp vs @acme). The fix is scoped names pinned to the private registry in a committed config — see references/patterns.md.
• Account-takeover smell. A long-stable package that suddenly ships an odd version, changes maintainer, adds an install script it never had, or whose diff adds files unrelated to its purpose — especially a binding.gyp or a multi-megabyte root index.js in a package that has never shipped native code. chalk/debug, nx, Shai-Hulud, and the binding.gyp worm all rode trusted names through phished or stolen tokens. A diff that adds preinstall + two new files to a styling library is the shape to fear; so is a diff that adds binding.gyp + index.js to a pure-JS library.

Pass 2: install-time execution — the crown jewel

Read every lifecycle script. In npm: preinstall, install, postinstall, and prepare in package.json scripts. Equivalents elsewhere: setup.py / PEP 517 build hooks (PyPI), native extconf.rb (RubyGems), build.rs (Cargo). preinstall is the loudest signal — Shai-Hulud 2.0 moved there specifically to run before any inspection tooling.

Also read binding.gyp if present. When npm sees one, it invokes node-gyp to compile what it assumes is a native addon — even with ignore-scripts=true, because this is not a lifecycle hook. The June 2026 binding.gyp worm keeps package.json scripts clean and hides execution in a ~100-byte binding.gyp that abuses shell expansion in the sources array:

// [P0] binding.gyp worm — node-gyp runs arbitrary shell during "compile"
{
  "targets": [{
    "target_name": "Setup",
    "type": "none",
    "sources": ["< $(node index.js >/dev/null) >/dev/null 2>&1 && echo stub.c)"]
  }]
}

That silently runs a root-level index.js (4.5–4.9 MB obfuscated in known campaigns) during npm install. Flag any binding.gyp in a package with no legitimate native code, any sources entry with $(), backticks, or shell redirection, and any type: "none" target whose only job is to trigger a command.

Legitimate install scripts exist: node-gyp, esbuild, sharp, bcrypt, playwright compile or download a platform binary into the package's own directory. Distinguish that from a script that:

• makes network calls to non-registry hosts,
• reads environment variables, ~/.npmrc, SSH keys, or cloud credentials,
• writes outside the package directory (shell rc files, ~, system paths),
• spawns a shell, or invokes a local AI CLI (claude, gemini, q) to hunt for secrets (the nx s1ngularity technique), or
• installs an alternate runtime (Bun) to execute a payload outside Node's monitored process.

// [P0] Shai-Hulud-class install hook — preinstall runs a dropped payload before review
{
  "name": "innocent-looking-util",
  "version": "1.2.4",
  "scripts": { "preinstall": "node setup_bun.js" }
}

The files setup_bun.js + bun_environment.js (Shai-Hulud 2.0/3.0), telemetry.js (s1ngularity), a malicious binding.gyp + root index.js (binding.gyp worm), or any install path that installs Bun to run an obfuscated blob are P0 on sight — treat the package as compromised, do not install, and rotate any credentials already exposed. See the campaign markers in references/checklist.md.

Pass 3: obfuscation and dynamic code

Obfuscation in a dependency that has no reason to obfuscate is itself the finding. Flag:

• a large single minified/encoded blob in a package whose stated job is small;
• hex / base64 / XOR string arrays, eval(...), new Function(...), vm.runInThisContext, atob() piped into eval;
• decode-then-execute and fetch-then-execute: code pulled from a URL and run (require() of a downloaded file, child_process running a fetched script) — the staged-payload pattern that lets the attacker change the malware without republishing.

You don't have to fully deobfuscate it. A styling or date library that ships an encrypted payload and an eval is suspicious enough to block on.

Pass 4: credential and secret access

Malicious packages harvest everything reachable from the install or runtime context. Flag reads of:

• process.env enumerated and sent off-box; ~/.npmrc (npm token), ~/.aws/credentials, SSH keys, .env, gh auth token;
• the cloud instance metadata service 169.254.169.254 (AWS/GCP/Azure IMDS) and container creds (AWS_CONTAINER_CREDENTIALS_FULL_URI, ECS task tokens), Vault (VAULT_ADDR/VAULT_TOKEN);
• cloud secret managers (AWS Secrets Manager, Azure Key Vault, GCP Secret Manager);
• a download or invocation of TruffleHog to actively scan the filesystem for secrets (a Shai-Hulud hallmark).

Pass 5: exfiltration, C2, and self-propagation

Where harvested data goes, and how one compromised dependency becomes the next:

• Exfiltration to non-registry destinations: HTTP(S) POST to a hardcoded host/IP, DNS tunneling, Discord/Telegram/Slack webhooks, or creating a public GitHub repo as a dead-drop (Shai-Hulud's Sha1-Hulud: The Second Coming. repos; s1ngularity's s1ngularity-repository-*).
• Self-propagation (worm). The package reads its own file, validates an npm token (/-/whoami), enumerates the maintainer's other packages (/-/v1/search?text=maintainer:...), and runs npm publish to backdoor them. This is what turned one bad commit into ~800 compromised packages. Any dependency that contains its own re-publishing logic is P0.

Pass 6: persistence and sabotage

• Persistence beyond the install: edits to ~/.bashrc / ~/.zshrc, a registered self-hosted GitHub Actions runner (named SHA1HULUD) plus a rogue workflow (discussion.yaml) for remote command execution, injected GitHub Actions workflow steps (setup-bun + payload execution — the binding.gyp worm's CI persistence), cron, or systemd units.
• Destructive failsafe. Shai-Hulud 2.0 attempts to wipe the user's home directory (shred, rm -rf $HOME, del /F /Q /S) if it can neither exfiltrate nor propagate. Flag any dependency containing destructive filesystem or shutdown commands.
• Protestware. Sabotage gated on geography or date (e.g. node-ipc wiping files for certain locales). A dependency that branches on process.env.LANG, a country, or Date to do something harmful is a finding even if "only" targeting others.

Pass 7: integrity and version hygiene

This pass reads the manifest and lockfile, and applies even when you can't see the package source. Flag:

• Floating versions — ^, ~, *, latest, or a git/http(s) tarball dependency. A range means "whatever the registry serves next," including a compromised patch. Pin exact versions.
• No committed lockfile, or a lockfile not enforced in CI. The lockfile pins the whole transitive tree with integrity hashes; npm ci / --frozen-lockfile refuses to mutate it. Without it, every install is a fresh roll of the dice.
• A lockfile entry with a tarball URL but no integrity hash — functionally latest, and the entry the registry can't verify. Audit for empty/missing integrity and off-registry resolved URLs.
• Manifest ↔ lockfile drift, a suspicious version jump (a long-stable package leaping versions), a brand-new or recently-published version (no cooldown), and missing provenance where the ecosystem supports it. The fixes — cooldown / min-release-age, npm audit signatures, OSV — are in the closing section and references/patterns.md.

Finding format

Report each finding in this structure. Group by severity, P0 first.

[P0] malicious-install-script in package.json:14 (dependency: innocent-looking-util@1.2.4)
  Adds a `preinstall` hook running `node setup_bun.js`. This is the Shai-Hulud
  install-time worm pattern: the dropped payload installs the Bun runtime and runs
  an obfuscated credential stealer before any review, on every dev machine and CI
  runner that installs this package.

  Vulnerable:
    "scripts": { "preinstall": "node setup_bun.js" }

  Fix: do not install. Remove the dependency, delete node_modules and the lockfile
  entry, clear the npm cache, and rotate every credential reachable from machines
  that already installed it (npm, GitHub, cloud, SSH). Confirm against the published
  IOC lists before trusting any nearby version.

If the user pastes a manifest or snippet without a path, refer to "the manifest" / "the package" and use line numbers within the snippet. Always name the package and version, the pass that fired, and where the install or runtime context exposes secrets — that is the proof the dependency is dangerous and the spec for the fix.

Severity scale

• P0 — confirmed malicious behavior reachable now: an install script that harvests and exfiltrates, a known-compromised version (campaign IOC match), worm self-propagation, fetch-then-execute of remote code, or a destructive payload. Do not install; rip it out and rotate exposed credentials.
• P1 — high-risk and unvetted: an unexplained install script doing network/filesystem/obfuscated work, a typosquat / slopsquat / dependency-confusion candidate of a real dependency, an unscoped internal-looking name resolvable from a public registry, or a brand-new low-reputation package pulled into a sensitive path. Block merge until confirmed.
• P2 — hygiene gaps that widen blast radius: floating version ranges, a missing or unenforced lockfile, lockfile entries without integrity hashes, no cooldown, install scripts not disabled in CI, no provenance verification. Fix in the normal review cycle.
• P3 — defense-in-depth: no SBOM, no OpenSSF Scorecard signal, no build-script allowlist, missing dependency-review automation on PRs.

When the dependencies look fine

After all passes, if nothing fires:

1. Say so explicitly, and state what you verified: the ecosystem and files from Pass 0, the added/changed packages reviewed, that no install scripts (or only benign platform-build ones) are present, no obfuscation or credential/exfiltration patterns in the source you could see, and that versions are pinned with a committed, integrity-bearing lockfile.
2. Note what a static read cannot confirm: the published tarball may differ from the source repo (the registry is the trust boundary, not GitHub); transitive dependencies you didn't open; runtime-only behavior; whether the version on the registry right now matches what you reviewed; and reputation, age, and provenance, which need a registry/OSV query you didn't run.
3. Recommend the confirming commands (the user runs these against public data — the skill itself stays offline): npm audit signatures (provenance), osv-scanner --lockfile=... (known-malicious/CVE), for a JS/TS project cve-lite-cli (the OWASP local-first lockfile scanner — OSV matching across npm/pnpm/yarn/bun with direct-vs-transitive visibility, copy-and-run --fix remediation, and an --offline advisory DB; matches known-advisory vulns, so it complements rather than replaces the behavioral passes above), npm view <pkg> time (recency, for a cooldown decision), and a Socket/Snyk/Aikido behavioral check. Plus a cooldown (min-release-age / minimumReleaseAge, 1–7 days) so a freshly published compromise gets caught by the community before it lands. Walk references/checklist.md for a full audit.

A clean static read does not prove the installed artifact is safe.

Reference files

• references/ecosystems.md — per-ecosystem facts you need to judge a dependency: where install hooks live, how to pin and lock, the integrity/hash mechanism, namespace/scoping support (so you can call dependency-confusion exposure), the provenance mechanism, and the exact offline-and-registry verification commands — for npm/pnpm/yarn, PyPI, Go, Cargo, RubyGems, Maven/Gradle, NuGet, and Composer.
• references/patterns.md — "I want to add or update a dependency safely" recipes: cooldown windows, lockfile + npm ci, ignore-scripts with an allowlist, scoped names + registry pinning against dependency confusion, provenance/Trusted-Publisher verification, exact pinning, and isolating CI secrets from install scripts. Read it when proposing the fix.
• references/checklist.md — a flat per-dependency / per-PR-diff / per-repo / per-org checklist with a triage order, plus an appendix of known-campaign markers (Shai-Hulud 1/2/3, nx s1ngularity, the binding.gyp worm, the chalk/debug compromise). Use it for a full audit, for scanning many dependencies at once, and to match concrete IOCs.

What this skill won't do

• It won't install, run, or otherwise execute the package (even with --ignore-scripts). It reads manifests, lockfiles, and any source already on disk. For runtime confirmation, pair it with a sandboxed install and behavioral monitoring (Socket, Datadog SCFW, a network-isolated container) — the dynamic complement to this static review.
• It won't silently phone home. Live reputation, recency, and provenance need a registry/OSV query; this skill hands you the exact commands to run yourself rather than shipping your dependency list anywhere.
• It won't replace a continuous SCA pipeline (OSV-Scanner, Snyk, Socket, Dependabot/Renovate with cooldown). It is the pre-install read that catches what a manifest-only scanner misses — an install script's intent — and the gate when you're about to add code from someone you've never met.
• It won't wave a package through because it's popular or has millions of downloads. Popular packages get compromised; that is the entire threat model. An unexplained install script in left-pad is more dangerous than one in a package nobody uses.