io.github.homeofe/supply-chain-guard

supply-chain-guard

Open-source supply-chain security scanner that runs locally and offline. It matches known-malicious packages, extensions, plugins, providers, container images and CI actions in 15 ecosystems, with tested matchers ready for more (see Ecosystem Coverage), reading manifests and lockfiles at any depth of a repository, including the transitive dependencies a lockfile pins; and it analyses what you install for malware behavior: GlassWorm, Vidar, Shai-Hulud, fake AI tool repos, account takeovers and 350+ threat indicators in all. It generates CycloneDX 1.6 SBOMs with real dependency inventories, grades SLSA provenance (parses and structurally validates in-toto/DSSE attestations), and correlates findings into attack-chain incidents. Supports EU Cyber Resilience Act SBOM and component-documentation work, and NIS2 supply chain risk-management measures.

Start in 30 seconds

Scan a project. No account, no configuration, and the scan itself makes no network request:

npm install -g supply-chain-guard
supply-chain-guard scan .

Without installing, start npx from outside the directory and pass its path, for example npx supply-chain-guard scan ./my-project from the parent directory. Do not start it through npx, npm exec or npm run from inside a directory you do not trust: npm then puts that directory's node_modules/.bin first on PATH and can run files from it before the scanner starts (GHSA-gqpg-9mjx-pv4w).

It exits 1 on a high finding or a scan that could not examine everything, and 2 on a critical finding, so it can gate a script as it is.

Keep the threat data current daily. New malicious packages are published every day, and so is this project's signed threat feed, without waiting for a release. Run this once a day with network access (the GitHub Action does it on every run):

supply-chain-guard feed refresh

It installs the signed daily feed and the historical package catalog into a per-user cache (see Catalog cache) that every scan uses, checks the Ed25519 signature first, and falls back to the latest release's feed if the daily channel is unreachable. Networks without internet access carry the same signed files in and use feed import (Air-gapped networks).

Gate every pull request:

- uses: actions/checkout@v4
- uses: homeofe/supply-chain-guard@v6.6.0

Let your AI coding agent check a package before it installs it (MCP):

npm install -g supply-chain-guard
claude mcp add supply-chain-guard supply-chain-guard mcp

Every release is published to npm from this repository's CI with a signed SLSA provenance attestation, and the Action installs that exact version. Each GitHub Release also carries the tarball with that provenance as a Sigstore bundle (.sigstore.json). To check one yourself:

gh attestation verify supply-chain-guard-X.Y.Z.tgz \
  --bundle supply-chain-guard-X.Y.Z.tgz.sigstore.json \
  --repo homeofe/supply-chain-guard --digest-alg sha512

Everything else, from output formats to policies, is further down: Quickstart, GitHub Action, For AI Coding Agents (MCP).

Contents

• Background
• What It Detects
• Installation
• Quickstart
• Output Formats
• CI Exit Code Control
• Filtering
• Internal Disclosure
• Policy Configuration
• Baseline Diffing
• Example Output
• Ecosystem Coverage
• How It Compares
• GitHub Action
• For AI Coding Agents (MCP)
• Live Threat Feed
• Install Guard
• Adding Custom Patterns
• Architecture
• EU Compliance (CRA / NIS2)
• Show that you scan
• Contributing
• Changelog
• License

Background

For a deep dive into how GlassWorm infiltrates the software supply chain and the detection techniques behind this tool, read the blog post: How GlassWorm Gets In and How We Locked It Out.

What It Detects

Known-Malicious Packages and Components

Package, extension, plugin and image identities are matched against the threat feed. This list is generated from the indicators that actually ship, so an ecosystem is only named as covered once there is something to match:

• Known-malicious indicators ship for 15 ecosystems: npm, PyPI, RubyGems, Composer (PHP), NuGet (.NET), Cargo (Rust), Go modules, Maven / Gradle / SBT / Bazel, Dart / Flutter (pub), Terraform / OpenTofu providers, Container images, GitHub Actions, VS Code / Open VSX extensions, Browser extensions (Chrome, Edge, Firefox) and JetBrains plugins.
• Homebrew has a tested matcher and ships an indicator, but is not counted: its one indicator (the compromised Trivy tap release 0.69.4) needs a version, and only the legacy Brewfile.lock.json records one; current Homebrew writes no lock file, so a Brewfile alone cannot match it.
• Matchers are built and tested, but no malicious package is publicly known yet, for 8 more: Swift Package Manager, CocoaPods, Hex (Elixir / Erlang), CRAN (R), Conan (C / C++), Terraform / OpenTofu modules, Helm charts and Ansible Galaxy. They report the day an indicator is published, through the importer or a curated entry.
• The files read per ecosystem are in Ecosystem Coverage.
• Manifests and lockfiles are read wherever they sit in the tree, so a monorepo service or a .NET project in src/App/ is covered, and a lockfile's transitive dependencies are matched, not only direct ones.
• A version pin fires only on the exact malicious release; a hijacked legitimate package is never blocked by name. Registry-specific identities stay separate (Marketplace vs Open VSX, Chrome vs Edge, public vs private registries), and a commit SHA or image digest matches under any repository name.

Malware Campaigns

• GlassWorm campaign markers and Solana blockchain C2
• Vidar/GhostSocks infostealers (April 2026 Claude Code leak campaign)
• Shai-Hulud self-replicating npm worm
• XZ Utils backdoor (CVE-2024-3094), SolarWinds SUNBURST, Codecov, ua-parser-js, coa/rc
• Fake AI tool repos (Claude Code, Copilot, Cursor, ChatGPT, OpenClaw lures)

Code-Level Threats

• Obfuscated execution: eval+atob, eval+Buffer.from, template literal eval, dynamic import()
• Invisible Unicode, RTL override, SVG script injection, steganography
• Shannon entropy analysis for encoded payloads
• Proxy handler traps, WebAssembly from external sources
• Scan-coverage transparency: files above the 5 MB content-scan limit are surfaced as FILE_TOO_LARGE_SKIPPED (info severity, never affects exit codes) instead of being silently skipped - padding a payload past the limit no longer hides it from the report
• Executable scripts without an extension are read in the language their shebang names (#!/bin/sh, #!/usr/bin/env node, python3, ruby, perl and others), and an extensionless file named like a git hook (pre-commit, pre-push, ...) is read as shell even without one, so hooks under scripts/hooks/ or .husky/ and bin/ launchers in a directory scan or an npm tarball are content-scanned. *.bats suites are read as bash and, like *.test.ts, count as test files, and Perl source is read as .pl/.pm too. A file with no extension, no shebang and no hook name is still not read

Supply Chain Attacks

• Install hook deep analysis (secret harvesting, download-exec chains, binary blobs)
• Levenshtein-based typosquatting detection against top 100 npm packages with known-safe whitelist
• Dependency confusion and namespace squatting
• Starjacking: in npm <pkg> mode, corroborates a package's claimed repository against the repo's own package.json and flags a repo borrowed from an unrelated popular project to inherit its stars/trust (conservative: monorepos, forks, related names, and unfetchable repos are not flagged)
• Known-bad version blocklist (axios, ua-parser-js, coa, rc, event-stream, node-ipc, colors, faker)
• Publishing anomaly detection (maintainer changes, version gaps, script additions)

Infrastructure & CI/CD

• GitHub Actions: unpinned actions, secrets exfiltration, encoded payloads, curl piping
• Agentic workflows (GitLost class): AI-agent steps and gh-aw .github/workflows/*.md that ingest untrusted issue/PR text, hold a cross-repo token, and can post publicly - the prompt-injection data-leak posture
• Dockerfile / Containerfile hardening: curl pipe, base images on a moving channel tag or without a digest, hardcoded secrets, SUID bits. These rules read Dockerfile instructions only (see docs/ARCHITECTURE.md); known-malicious images are matched separately in Dockerfiles and in every YAML image: value (Compose, Kubernetes, workflow containers), see Ecosystem Coverage
• Terraform/IaC: inline scripts, external modules, hardcoded secrets; known-malicious providers and registry modules are matched as listed in Ecosystem Coverage
• Package manager configs (.npmrc, .yarnrc, pip.conf): HTTP registries, exposed tokens
• Git hooks and submodule security

Repository Trust Signals

• GitHub repo metadata analysis (account age, star-farming, single-commit repos)
• Release artifact scanning (.exe, .7z, double extensions, LNK shortcuts, PE magic)
• README lure detection (leaked/pirated/urgency language)

Prompt Injection Against AI Coding Agents (v5.2.19)

Detects LLM-control tokens embedded in package READMEs that target downstream AI coding agents (Claude Code, Cursor, Copilot) reading the docs on behalf of a human developer. The example tokens below are HTML-escaped in the raw README so the patterns do not flag this documentation itself - they render normally in any markdown viewer:

• <system-reminder> / <system-prompt> (Anthropic family)
• <|im_start|> / <|im_end|> ChatML (OpenAI, Llama, Mistral, Qwen)
• [INST] / [/INST] (Mistral, Llama instruction-tuned)
• <|system|> / <|user|> / <|assistant|> (Phi, Gemma, Granite, generic role tokens)
• Natural-language jailbreak phrasing ("ignore previous instructions")

Credential Detection

• AWS access keys (AKIA/ASIA), GitHub tokens (ghp_/gho_), npm tokens
• SSH private keys, generic API keys, PEM private keys

Internal Topology Disclosure

Not credentials: the map of your network that a public repository hands out for free. Private and non-routable addresses (RFC1918, CGNAT, link-local, IPv6 ULA), internal-only hostnames (.internal, .local, .lan, .corp, .home, .intranet), clone URLs pointing at a forge that is not a known public one, developer home-directory paths, and internal service endpoints. Reported at medium (reconnaissance value, not compromise), with an optional deny-list for the names only your project knows. See Internal Disclosure.

Dead-Drop Resolver / C2 Detection

• Steam Community profiles, Telegram channels, Pastebin, GitHub Gists
• DNS TXT records, DNS-over-HTTPS, dynamic WebSocket URLs
• Known C2 domains and IPs (from IOC blocklist)

Correlation Engine (v4.2)

Links individual findings into incident-level attack chains:

• "GlassWorm Campaign" (marker + eval + exfiltration)
• "Vidar Stealer Infection" (dead-drop + browser theft + dropper)
• "npm Account Takeover" (maintainer change + install hooks + C2)
• "Fake Repository Malware" (lure + exe release + new account)
• 15+ correlation rules with confidence scoring

Trust Breakdown (v4.2)

Multi-dimension trust scoring for package and repository inspections:

• Publisher Trust (40%) / Code Quality (30%) / Dependency Trust (20%) / Release Process (10%) (all 4 dimensions populated for npm, pypi, repo, and remote scan <github-url> modes; local directory scans evaluate Code Quality and Dependency Trust with renormalised weights).

Installation

Requires Node.js 22 or newer. Every release runs its complete test suite, and installs and executes its own packed tarball, on Node 22 and on Node 24, the current Active LTS. Full policy, including what the package is published from and what the Action and container image run on: docs/node-support.md.

npm install -g supply-chain-guard

Or use directly with npx, started from outside the directory you scan:

npx supply-chain-guard scan ./my-project

pre-commit

Run the scanner as a pre-commit hook (Python-ecosystem teams get the same gate without touching npm). Add this to your .pre-commit-config.yaml:

repos:
  - repo: https://github.com/homeofe/supply-chain-guard
    rev: v6.6.0
    hooks:
      - id: supply-chain-guard

The scanner writes its risk history to .scg-history/ in the scanned repo; it is not written when --no-history is set, which the hook now uses. For plain scans without that flag, add the folder to your .gitignore.

If a file in .scg-history/ cannot be read, the scan says so and fails. The two stores there, risk-history.json and triage-decisions.json, are the baseline that trend, forecast and triage-governance rules compare against. A store that is absent is a first scan and stays silent, which is the normal case on a fresh checkout or a hosted runner. A store that exists but does not parse, because a scan was interrupted mid-write or the file was edited by hand, is lost evidence, and the two are deliberately not reported the same way: the scan emits RISK_HISTORY_UNREADABLE or TRIAGE_STORE_UNREADABLE at high, sets partialScan: true, and exits nonzero regardless of --fail-on, because an unusable baseline is an indeterminate result rather than a clean one. The unreadable file is left on disk rather than overwritten, so complete entries can still be recovered from it, usually by closing the truncated JSON array by hand. Delete the file to start a new baseline once you have decided the old trend is expendable. --no-history does not silence this: that flag stops the write, not the read, so a corrupt store still degrades the verdict and is still reported.

The hook scans the repository root on every commit and fails on high or critical findings.

Docker

Run the scanner without a Node toolchain via the official multi-arch image (linux/amd64, linux/arm64), published to GHCR on every release tag:

docker run --rm -v ${PWD}:/scan ghcr.io/homeofe/supply-chain-guard:6.6.0 scan /scan

${PWD} works in bash, zsh, and PowerShell; in cmd.exe use %cd% instead.

The image keeps the feed and catalog cache in /cache (SCG_CACHE_DIR), so it is gone after --rm. To keep it across runs, mount a named volume there, and run the refresh once a day to pick up the daily feed:

docker run --rm -v scg-cache:/cache ghcr.io/homeofe/supply-chain-guard:6.6.0 feed refresh
docker run --rm -v scg-cache:/cache -v ${PWD}:/scan ghcr.io/homeofe/supply-chain-guard:6.6.0 scan /scan

Quickstart

# Scan a local directory
supply-chain-guard scan ./my-project

# Scan a GitHub repo (includes trust signal analysis)
supply-chain-guard scan https://github.com/user/repo

# Analyze a GitHub repo for trust signals + malware
supply-chain-guard repo https://github.com/user/repo

# Scan an npm package (downloads without installing)
supply-chain-guard npm suspicious-package-name

# Scan a PyPI package
supply-chain-guard pypi suspicious-package

# Scan a VS Code extension
supply-chain-guard vscode publisher.extension-name

# Scan a VS Code extension from the Open VSX registry (VSCodium etc.)
supply-chain-guard vscode publisher.extension --registry openvsx

# Detect dependency confusion
supply-chain-guard confusion ./my-project

# Scan an entire GitHub organization
supply-chain-guard org my-github-org

# Scan only files changed since a commit (diff mode)
supply-chain-guard scan ./project --since HEAD~5

# Opt in to public registry queries (requires network; sends package names to npm and PyPI)
supply-chain-guard scan ./project --check-registry

# Expand every repeated text finding (text groups by rule and file by default)
supply-chain-guard scan ./project --all-findings

# Opt into correlated two-tier gating and composite risk scoring
supply-chain-guard scan ./project --two-tier

# Query resolved npm coordinates plus OSV, EPSS, CISA KEV and Scorecard
# This requires network access and implies --two-tier
supply-chain-guard scan ./project --external-intel

# Supply a previously obtained Scorecard value; also implies --two-tier
supply-chain-guard scan ./project --scorecard 8.4

# Monitor a Solana C2 wallet
supply-chain-guard monitor <wallet-address> --once

Output Formats

supply-chain-guard scan ./project                # Human-readable text (default)
supply-chain-guard scan ./project --format json   # JSON (for CI/CD pipelines)
supply-chain-guard scan ./project --format html   # Standalone HTML report
supply-chain-guard scan ./project --format markdown # Markdown (for PR comments)
supply-chain-guard scan ./project --format sarif  # SARIF 2.1.0 (GitHub Code Scanning)
supply-chain-guard scan ./project --format sbom   # CycloneDX 1.6 SBOM with real dependency inventory
supply-chain-guard scan ./project --sbom-output sbom.json  # The same SBOM, written to a file instead of stdout
supply-chain-guard scan ./project --format badge   # Shields.io endpoint JSON
supply-chain-guard scan ./project --format gitlab  # GitLab Dependency Scanning report (security-report-schemas 15.2.4, see examples/gitlab-ci.yml)
supply-chain-guard scan ./project --format markdown --json-output canonical.json  # Same scan, human report plus canonical JSON

Badge

Publish the badge JSON from CI (gist or gh-pages), then point Shields at it:

The scan exits non-zero when it finds high/critical issues - exactly when the badge MUST update to red. Neutralize the exit code on the generate step (or use if: always() on the publish step) so a bad scan never freezes the badge green:

- name: Generate badge JSON
  run: supply-chain-guard scan . --format badge > badge.json || true
- name: Publish to gist
  if: always()
  run: gh api gists/YOUR_GIST_ID -X PATCH -F "files[badge.json][content]=@badge.json"
  env:
    GH_TOKEN: ${{ secrets.BADGE_GIST_TOKEN }}

![supply-chain-guard](https://img.shields.io/endpoint?url=https://gist.githubusercontent.com/YOUR_USER/YOUR_GIST_ID/raw/badge.json)

CI Exit Code Control

supply-chain-guard scan ./project --fail-on critical  # Fail only on critical
supply-chain-guard scan ./project --fail-on high       # Fail on high or above
supply-chain-guard scan ./project --fail-on info       # Fail on any finding

--min-severity may reduce report noise, but it cannot be stricter than the active --fail-on gate because that would hide findings required for the exit verdict. Invalid combinations fail before scanning. Incomplete coverage also exits nonzero regardless of the severity threshold and is reported as partialScan: true in JSON.

Filtering

supply-chain-guard scan ./project --min-severity high
supply-chain-guard scan ./project --exclude SOLANA_MAINNET,HEX_ARRAY

Internal Disclosure

Secret scanners answer one question: did a credential get committed? This family answers a different one: did our internal topology get committed?

Internal hostnames, private LAN addresses, self-hosted forge URLs, developer home directories and private repository names are not credentials, so no secret scanner reports them. Together they are the reconnaissance map an attacker draws before touching anything: what exists, what it is called, where it listens, and who works on it. It leaks through the same boring channels every time. A copied clone command in a README. A .env.example that kept the real staging host. A comment with the path the author built from. A lockfile pointing at an internal registry. None of it is a secret, all of it is intelligence, and it stays in git history long after the file is fixed.

The rules are shape-based, so they work on a repository whose owner has configured nothing at all. You never have to write down what your infrastructure is called in order to be protected from publishing it.

What it catches

Severity follows the host, not the rule. A host with no domain part is the weakest signal in the family whichever rule reports it, so a dotless payments host with a port is low, exactly like the same host without one. Only a dotted internal name or a private address makes an endpoint medium.

INTERNAL_GIT_REMOTE is the one worth pointing at: it finds a self-hosted forge without anyone having to name it. Any clone URL that is not github.com, gitlab.com, bitbucket.org, codeberg.org, git.sr.ht and the other well-known public hosts is, by shape alone, a forge somebody runs privately.

Severity is deliberately not inflated

Topology is reconnaissance value, not compromise, so the family reports medium and low. high and critical stay reserved for credential-shaped findings, which the existing rules already own.

Practically: the default gate exits non-zero on critical and high only, so upgrading cannot turn a passing build red. --fail-on high and --fail-on critical are equally unaffected. Two things do change: the risk score rises (each medium adds points), and a pipeline that runs --fail-on medium or lower will see the new findings. If you would rather not see them at all, they respect every existing control:

rules:
  disable:
    INTERNAL_PRIVATE_IP: RFC1918 addresses are expected in this repository's fixtures
    INTERNAL_HOSTNAME: internal names are already covered by a separate review

The parser reads block style only; a flow sequence on one line (disable: [A, B]) is reported as POLICY_UNKNOWN_KEY and disables nothing.

False-positive controls

A rule that screams on every README gets switched off, and a switched-off rule protects nothing. Three independent layers keep this quiet.

1. The reserved documentation space never fires. Anything written the way the RFCs intend is invisible to these rules:

• addresses from RFC5737: 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24
• names from RFC2606: example.com, example.org, example.net, the .example TLD, .invalid, .test
• loopback and the unspecified address, localhost URLs
• placeholder and CI account names in paths: runner, vscode, ubuntu, jenkins, you, dev, user, Public and more
• container and compose service aliases in single-label URLs: db, redis, api, minio, nginx, and the unix / npipe pseudo-hosts that mean "a UNIX domain socket, not a machine"
• a CIDR range such as 10.0.0.0/16 is a subnet layout, not a host, so it is not reported (a /32 host route is)
• universal infrastructure constants, which are the same address in every installation on earth and therefore describe nobody's topology: the cloud metadata endpoint 169.254.169.254 (and the ECS 169.254.170.2, Amazon Time Sync 169.254.169.123, Alibaba 100.100.100.200), the Kubernetes defaults 10.96.0.1 and 10.96.0.10 and the k3s 10.43.0.1 / 10.43.0.10, the default service and pod CIDRs (10.96.0.0/12, 10.244.0.0/16, 10.42.0.0/16), the Docker bridge gateway 172.17.0.1, and the Docker Desktop names host.docker.internal and friends. A real address inside the same ranges is still reported.

2. A match has to sit where its rule can mean what it claims.

• An internal-only TLD has to be the last label of the name, so config.internal.timeout, com.acme.internal.util and settings.local.json are never hosts.
• A name preceded by a path separator is a file, not a host: ./config.local, src/config.local and ../lib/settings.local are module specifiers. https://db.example.corp/, //registry.svc.example.corp/ and git@forge.internal.example:... still are hosts.
• A name followed by ( is a method call: res.local(name, val) in a changelog is not a machine.
• In programming-language sources a bare dotted name is only reported inside a string literal, a comment or a URL, because config.internal.timeout and state.local.value are property accesses. Data and config files (.yml, .json, .toml, .env, Dockerfile, lockfiles) carry unquoted values, so no quotes are required there.
• /Users/ is matched case-sensitively and :id, {id}, <id> and ${user} are rejected after the account segment, so app.get("/users/:id"), "/users/{id}" and app.get("/users/profile/edit") are routes, not macOS home directories. A Windows path keeps both spellings, because C:\users\ is unambiguous.

3. The surface decides which rules stay armed.

The reasoning changed here, deliberately. Documentation used to be excluded wholesale, which silenced precisely the case this family exists for: a private address or a developer path inside a README is one of the most common ways internal topology reaches a public repository, and a /home/<name>/ in a pasted stack trace is a real leak, not a teaching aid. The reserved namespace above is what protects a writer who follows the RFCs, and it works on every surface. What stays excluded is what measurement showed to be noise rather than signal: inline code spans (on the sample used to tune this, eight findings, all of them API signatures or documented examples), placeholder fences, and files whose whole purpose is to show a shape.

Two things are reported on purpose even though they can be examples. Kubernetes in-cluster names (<service>.<namespace>.svc.cluster.local) name your service inventory. And an address or path inside a code comment (a JSDoc @example block, say) is reported, because a comment is the single most common place a real host gets written down and nothing distinguishes an illustrative address from a real one there. Use RFC5737 addresses in code examples, or suppress by path.

Bounded cost

A generated bundle is one 800 KB line, and a rule family that takes minutes on it is a rule family that gets switched off. Four limits keep the cost flat, and none of them is silent:

• line offsets are computed once per file and binary-searched, and each line's quoting and comment structure is computed once per line rather than once per match
• a line longer than 2000 characters is skipped, the way an oversized file is skipped by FILE_TOO_LARGE_SKIPPED
• at most 25 findings per pattern and 100 per file. Two rules (INTERNAL_DEV_PATH and INTERNAL_GIT_REMOTE) are each written as two patterns, so those can reach 50 from a single file. When the per-file cap drops findings it keeps the most severe ones.
• at most 20000 candidate matches per rule per file, which bounds the case where nearly everything is filtered out and so produces no findings to count

Whenever a limit is reached, the file gets one INTERNAL_DISCLOSURE_TRUNCATED finding at info severity naming the limit. A scanner that quietly stopped looking is indistinguishable from a repository with nothing to find, and that is not a trade this tool makes.

On top of that, everything else already in this tool applies: suppress with a path: glob, ignore: globs, --exclude, --min-severity, and inline // scg-ignore-next-line INTERNAL_HOSTNAME reason.

The deny-list, and its paradox

Shape rules cannot know that sample-service is one of your private repositories. A deny-list can. But a list of your internal hostnames committed to a public repository is exactly the leak you were trying to prevent, so there are three ways to configure one and only one of them puts plaintext in the repo.

# yaml-language-server: $schema=./node_modules/supply-chain-guard/policy-schema.json

# Whether the downloadable historical catalog must be present for a scan to
# count as complete. "optional" (the default) reports THREAT_FEED_CATALOG_MISSING
# and carries on; "required" raises it to critical.
catalog: optional

internalDisclosure:
  # (a) HASHED. Publishable: the digest hides the term from a reader and from
  #     grep. It is not a vault - see "What hashing is worth" below.
  #     Generate with: supply-chain-guard internal-hash forge.internal.example
  hashedTerms:
    # sha256("forge.internal.example") and sha256("acme/sample-service"),
    # so you can verify the recipe below against these two lines.
    - 113fbef8cb1afd8d755cfa3c5b954244973c1b4182824c64755235de60a3d106
    - 479ec322598b9047aaac200d2c1c2d5ab9658ce50ef7e60dc1081741f037d7d3

  # (b) EXTERNAL. Full regex/plaintext patterns that must never be published.
  #     Gitignore this file, or provision it on the runner. Matches are
  #     reported REDACTED, so the report cannot leak it either.
  externalFile: .scg-internal-terms.local

  # (c) PLAINTEXT. For a private repository scanning itself, or terms that
  #     are not sensitive. Literals, or /regex/flags.
  patterns:
    - sample-service
    - /build-\d{2}\.corp/

Hashing recipe. Normalisation is trim, then lowercase. Then sha256, lowercase hex. That is the whole rule, so any tool can reproduce it:

# Bundled helper (prints only the digest, so nothing sensitive rides along)
supply-chain-guard internal-hash forge.internal.example

# The same digest, without this tool
printf '%s' "forge.internal.example" | tr 'A-Z' 'a-z' | sha256sum

What hashing is worth, honestly.

As a matcher it is exact-token matching, nothing more. A token is a maximal run of letters, digits, ., _ and - (so https://forge.internal.example/x yields forge.internal.example), plus an org/repo pair and a .git suffix stripped, all lowercased. A hashed entry for forge.internal.example therefore matches that host but not sub.forge.internal.example, and there is no way around it: a scanner that could match substrings of a hash would be a scanner that could recover the term. When you need substring or regex power, use externalFile (b).

As a secret it buys less than "hashed" suggests, and it is worth saying plainly. An unsalted, single-round sha256 of a low-entropy value is dictionary-attackable: hostnames come from a small, guessable space (a short site or service word, a two-digit index, one of a handful of internal TLDs), so anyone with your repository can hash candidate names until one matches. What a digest genuinely buys is that the term is not sitting in the file to be read, copied or grepped, and that it does not travel into a report, a log or a screenshot. That is real, and it is not the same as being unrecoverable.

If you need the stronger claim, salt it with a value that lives outside the repository:

export SCG_INTERNAL_HASH_SALT="$(openssl rand -hex 16)"    # store it wherever your CI secrets live
supply-chain-guard internal-hash forge.internal.example    # generates a salted digest

internalDisclosure:
  hashSalted: true          # says the digests below are salted
  hashedTerms:
    - <salted digest>

The salt has to be held outside the repository to be worth anything: a salt committed next to the digests is hashed by the same reader who reads them, which is why there is no config key for the salt itself. hashSalted: true is what keeps this fail-visible - a scan that runs without the salt matches nothing, which looks exactly like a clean repository, so the declaration turns that silence into an INTERNAL_DENYLIST_UNAVAILABLE finding instead.

An environment variable does the same thing as externalFile without touching the committed config at all:

SCG_INTERNAL_DISCLOSURE_FILE=~/.config/scg/internal-terms supply-chain-guard scan .

The external file is one entry per line, # for comments, sha256:<digest> for a hashed entry, /pattern/flags for a regex, anything else is a case-insensitive literal. If the file is configured but absent (a shared CI runner that never received it), you get an INTERNAL_DENYLIST_UNAVAILABLE finding at info severity rather than silence: a deny-list that quietly stopped running looks exactly like a repository that is clean. An entry that cannot be compiled is reported the same way (INTERNAL_DENYLIST_INVALID_ENTRY, medium). Neither finding ever prints the entry, and the environment variable is named but its value is not, because a path can itself contain an account name.

The two sources are not equally trusted, and the difference is deliberate. SCG_INTERNAL_DISCLOSURE_FILE is set by whoever runs the scan, so it may name any path on the machine and carry any pattern. internalDisclosure.externalFile and internalDisclosure.patterns live in the committed policy file, which travels inside the repository being scanned, and scanning a repository you do not own is the ordinary case for this tool. Entries from there are therefore bounded:

• externalFile must stay inside the scanned directory. An absolute path is refused, a relative path that climbs out with .. is refused, and so is one that leaves through a symbolic link. The file is not opened, so nothing about a path outside the tree reaches the report. The bound is the scanned directory and nothing narrower: a path that stays inside it is still read, .git/config included, so a committed externalFile can still point at whatever your runner wrote into the workspace. Matches from it stay redacted.
• A regular expression from patterns, or from an externalFile that is inside the tree, is capped at 200 characters and limited to a safe subset: no quantified group at all ((a+)+, (a|a)+, (a|ab)*, (a+){2,30}), no backreference and no lookaround. Literals, unquantified groups and quantified single characters or classes ([a-z0-9.-]+, ab[0-9]{3}) are accepted. A quantified group can take exponential time to report no match, so one committed line would otherwise occupy a runner until the workflow times out. A pattern from the operator's own file or environment variable is not restricted.
• Whatever survives those checks runs under a wall-clock budget for the whole scan. On overrun the file reports INTERNAL_DISCLOSURE_TRUNCATED rather than running on.

A refusal is an INTERNAL_DENYLIST_REFUSED finding at medium severity, and like every other coverage finding it marks the scan partial rather than passing quietly. In the published Action a partial scan exits 1 on its own, independently of fail-on. None of this applies to the environment-variable source.

Two limits of the shape check, both worth knowing before you upgrade.

It refuses more than it has to, and the shape it most often refuses is the ordinary one. A chained label group is how an internal hostname is normally written, and it is rejected even though it is linear in practice:

internalDisclosure:
  patterns:
    - /(?:[a-z0-9-]+\.)+corp\.example/   # REFUSED: quantified group holding "+"
    - /[a-z0-9.-]+\.corp\.example/       # accepted, and matches the same hosts

If you have the first form today, in patterns or in your own gitignored externalFile, rewrite it before you upgrade. Left as it is, the term stops being looked for, the scan becomes partial, and the Action exits 1.

It also refuses less than it has to, so an accepted pattern is not a promise about time. The check reads the source text, which cannot see ambiguity that comes from overlapping alternation, so /(a|a)+$/ and /(a|ab)+$/ are accepted and are still catastrophic, and the wall-clock budget cannot interrupt a match that is already running. Availability from a committed pattern is narrowed here, not closed; the remaining case is tracked on issue 169.

One more note on the paradox. allowlist.domains also answers INTERNAL_HOSTNAME, INTERNAL_SERVICE_ENDPOINT and INTERNAL_GIT_REMOTE for a given host, which is convenient and publishes the host name. If that is not acceptable, suppress by path instead, which names nothing:

suppress:
  - rule: INTERNAL_HOSTNAME
    reason: vendored upstream config, reviewed
    path: vendor/**

Policy Configuration (v4.4)

Create .supply-chain-guard.yml in your project root to customize behavior:

rules:
  # Every disabled rule needs a written reason, the same bar `suppress` has met
  # since v5.3. The bare list form (`- HEX_ARRAY`) still disables the rule and is
  # reported as POLICY_DISABLE_NO_REASON.
  disable:
    HEX_ARRAY: minified vendor bundles in this repository, reviewed 2026-08
    CHARCODE_OBFUSCATION: same bundles, same review
  severityOverrides:
    GHA_UNPINNED_ACTION: medium

allowlist:
  packages:
    - internal-utils
  domains:
    # Suppresses THREAT_INTEL_MATCH / IOC_KNOWN_C2_DOMAIN findings whose matched
    # host is this domain or a subdomain of it.
    - company.example.internal
  githubOrgs:
    # Trusted action publishers. Suppresses the ownership-trust findings
    # (GHA_THIRD_PARTY_ACTION, GHA_TAG_NOT_SHA) for actions owned by these
    # orgs. Pinning and known-malicious-SHA rules stay armed: trusting an org
    # says who publishes the code, not that every version of it is safe.
    - my-org

# Skip files matched by these path globs (** / * / ?) during the scan. These
# files are never opened, so nothing about them reaches the report except the
# policy block below. Each glob needs a written reason; the bare list form
# (`- vendor/**`) still skips the path and is reported as POLICY_IGNORE_NO_REASON.
ignore:
  "vendor/**": third-party code, tracked by the upstream project's own scanning
  "**/*.min.js": build output, scanned at source instead

suppress:
  - rule: RELEASE_EXE_ARTIFACT
    reason: Legitimate Windows installer
  # Optional path glob: suppress a rule only under a matching path.
  - rule: EVAL_ATOB
    reason: Vendored third-party bundle, reviewed
    path: vendor/**

baseline:
  file: .scg-baseline.json

Findings can also be suppressed inline with a comment on the line directly above them: // scg-ignore-next-line RULE reason (JS/TS) or # scg-ignore-next-line RULE (Python/YAML/shell). Inline comments apply to local directory scans only, and never hide a high or critical finding in a cloned GitHub repository, an MCP scan_directory call, or an npm, PyPI or VS Code package scan.

Where the policy is read from, and what that means on a pull request

For a local directory scan the policy file is read from the directory being scanned, and from nowhere else. There is no flag, environment variable or Action input that points the scanner at a policy outside the scan target.

A scan whose target is a cloned GitHub repository URL, and the MCP scan_directory tool, never load a policy file from the scanned tree (library callers can set trustTargetPolicy: false to get the same). The tree there belongs to someone else.

On a pull_request event the checkout materialises the head of the proposing branch, so the policy that governs the scan is the one on the branch under review, not the one on your default branch. A change that adds .supply-chain-guard.yml alongside the code it excuses is applying its own policy to itself. Anyone who can push a branch can therefore narrow the scan of that branch.

That is a property of reading policy from the tree, and it is stated here rather than left to be discovered. What it is not is silent:

• Every narrowing is named in the report, in all nine output formats, including the markdown pull request comment the Action posts by default. A scan narrowed by policy can no longer be mistaken for a clean scan in any format, including ignore:, which removes files before any rule opens them and used to leave no trace anywhere.
• A narrowing declared without a written reason is reported as a finding (POLICY_DISABLE_NO_REASON, POLICY_IGNORE_NO_REASON, POLICY_SUPPRESSION_NO_REASON), so an undocumented exclusion costs a line in the report rather than nothing.
• When the policy, or an inline scg-ignore-next-line comment, removes, ignores or downgrades a high or critical finding, the scan runs a second pass without them and the report gains a medium POLICY_SUPPRESSED_SEVERE finding that lists the rule ids and counts, plus riskLevelBeforePolicy and maxSeverityBeforePolicy (JSON and the "RISK BEFORE POLICY" text line). The exit code is not changed by default, because suppressing a false positive is the intended use of the mechanism. A scan with neither stays single-pass.

If your threat model includes an untrusted proposer, the controls that actually hold are outside this tool: require review on .supply-chain-guard.yml through CODEOWNERS, or scan a base-ref checkout in a separate job. Treat a policy file in a pull request diff as a change to your security gate, because it is one.

Baseline Diffing (v4.4)

Only report NEW findings (ignore known baseline):

# Save current findings as baseline
supply-chain-guard scan ./project --save-baseline .scg-baseline.json

# On subsequent scans, only show new findings
supply-chain-guard scan ./project --baseline .scg-baseline.json

Example Output

╔══════════════════════════════════════════════════════════════════════════════╗
║  supply-chain-guard                                                  v5.1.0 ║
╚══════════════════════════════════════════════════════════════════════════════╝

  Target         ./suspicious-package
  Type           directory  ·  18 / 18 files scanned
  Duration       142 ms
  Time           2026-04-07T12:00:00.000Z

┌────────────────────────────── DETECTED RISK ───────────────────────────────┐
│                                                                              │
│   83 / 100   █████████████████████████████████░░░░░   CRITICAL             │
│                                                                              │
└──────────────────────────────────────────────────────────────────────────────┘

┌──────────────────────────── FINDINGS SUMMARY ───────────────────────────────┐
│  CRITICAL      3  ████████████████████████████████                          │
│  HIGH          1  ██████████                                                 │
│  MEDIUM        0  ────────────────────────────────                           │
│  LOW           0  ────────────────────────────────                           │
│  INFO          0  ────────────────────────────────                           │
└──────────────────────────────────────────────────────────────────────────────┘

┌──────────────────────────────── FINDINGS ───────────────────────────────────┐
│                                                                              │
│  [CRITICAL]  DEAD_DROP_STEAM                                                │
│              Steam Community profile URL used as dead-drop C2 resolver      │
│              src/config.js:12                                                │
│              match  https://steamcommunity[.]com/profiles/76561198...       │
│              fix    Remove external URL resolution; use static configuration │
│                                                                              │
│ ············································································· │
│                                                                              │
│  [CRITICAL]  VIDAR_BROWSER_THEFT                                            │
│              Browser credential file access (infostealer pattern)           │
│              src/steal.js:45                                                 │
│              match  AppData[...]Google[...]Chrome[...]Login Data             │
│              fix    Never access browser credential stores                   │
│                                                                              │
│ ············································································· │
│                                                                              │
│  [CRITICAL]  DROPPER_TEMP_EXEC                                              │
│              Dropper: file written and executed from temp directory          │
│              src/loader.js:23                                                │
│              match  saveFile(tmpdir, payload); exe‹c›(tmpPath)              │
│              fix    Remove dropper logic; audit all exec() call sites        │
│                                                                              │
└──────────────────────────────────────────────────────────────────────────────┘

┌─────────────────────────── TRUST BREAKDOWN ─────────────────────────────────┐
│  Publisher       ██████░░░░░░░░░░░░░░░░░░░░░░░░░░░░  20/100               │
│  Code            █████████░░░░░░░░░░░░░░░░░░░░░░░░░  30/100               │
│  Dependencies    ████████████████████████████████████ 100/100              │
│  Release         ██████████████████████████░░░░░░░░░  80/100               │
│────────────────────────────────────────────────────────────────────────────│
│  Assessed        █████████████░░░░░░░░░░░░░░░░░░░░░░  48/100               │
│  4/4 trust dimensions assessed                                             │
└──────────────────────────────────────────────────────────────────────────────┘

┌──────────────────────────── CORRELATED INCIDENTS ───────────────────────────┐
│                                                                              │
│  [CRITICAL]  Vidar Stealer Infection  95% confidence                        │
│  Multiple infostealer indicators: dead-drop resolvers for C2,               │
│  browser credential theft, and crypto wallet targeting.                     │
│  Indicators: DEAD_DROP_STEAM, VIDAR_BROWSER_THEFT, DROPPER_TEMP_EXEC       │
│                                                                              │
└──────────────────────────────────────────────────────────────────────────────┘

Ecosystem Coverage

Two different claims live here, and they are proven differently.

Known-malicious identity matching. For every ecosystem below, a directory scan reads the listed files at the scan root and at any depth below it, extracts the package, extension, plugin, provider, image or action identities, and matches them against the threat feed: the bundled indicators, and the downloadable catalog after feed refresh. A version pin fires only on the exact malicious release; a range or a constraint in a manifest leaves the version unknown, so only a whole-name entry can match there.

This table is generated from src/ecosystem-coverage.json and checked by the build (check:coverage); it is not written by hand. Every row is proven by coverage-matrix.test.ts, which puts an indicator into each listed file format, at the scan root and one directory down, runs a real scan and requires the rule to report it exactly once. A format listed here without such a test fails the test suite. "Indicators shipped" says whether any indicator exists today; "none yet (matcher ready)" means the matcher is proven but no malicious package is known in that ecosystem yet, and the importer or a curated entry will fill it.

Behavior and hardening analysis. Independent of the feed, these read what a package or repository actually does:

How It Compares

supply-chain-guard is the malware / behavior / campaign-IOC layer: it statically scans what you actually install (node_modules, packages, Docker images, VS Code extensions, Actions workflows, IaC) for malicious behavior and known campaign indicators, entirely locally. It does NOT do CVE lookups: pair it with osv-scanner or npm audit for known vulnerabilities. Most tools below measure a different axis and are complementary, not competitors.

There is one axis where it goes somewhere the others do not go at all. Credential scanners such as gitleaks and trufflehog hunt secrets, and they are good at it; nothing in that category hunts what a repository gives away about the network it came from. That is what Internal Disclosure covers: internal hostnames, private addresses, self-hosted forge URLs and developer paths, reported as reconnaissance risk rather than as a leaked credential.

Honest caveats: Socket's registry-wide behavioral detection is deeper than anything a local scanner can do, at the cost of a closed engine and cloud analysis. Scorecard is the industry standard on its axis (upstream hygiene prediction) and supply-chain-guard does not replace it. OSV-Scanner and npm audit do flag known-malicious packages: the gap is advisory lag, not a missing capability.

Pairs well with

• CI one-two punch: run osv-scanner --lockfile=package-lock.json for known CVEs and MAL- entries, then supply-chain-guard scan . for behavioral and campaign-IOC threats in the installed tree. Two axes, one job, both exit-code gated.
• Zero-install npm baseline: npm audit --audit-level=high plus npx supply-chain-guard scan ./my-project, started from the parent directory, covers advisory-known vulnerabilities and unreported malware without adding a single dependency.
• Pre-install vetting of a suspicious package: guarddog npm scan <pkg> for an independent heuristic score, plus supply-chain-guard npm <pkg> for campaign-IOC and install-hook analysis, before it ever touches your machine. ## EU Compliance (CRA / NIS2)

supply-chain-guard produces artefacts and findings that support compliance work under two EU regulations that apply to software manufacturers. It does not make an organisation compliant: compliance remains the responsibility of the organisation deploying the software, and the mapping below describes what the tool produces, not a legal assessment.

Cyber Resilience Act (CRA)

The CRA requires manufacturers of products with digital elements to identify and document the components they ship, to address vulnerabilities in those components, and to be able to reason about the integrity of what they build on. supply-chain-guard contributes to each of those activities:

• Component inventory: generates a CycloneDX 1.6 SBOM from the real resolved dependency tree, as a machine-readable component list you can attach to technical documentation. The inventory is built from npm only, and specifically from package-lock.json (lockfile version 2 or later) for the full transitive tree, falling back to the direct dependencies declared in package.json. pnpm-lock.yaml, yarn.lock and bun.lockb are not read, and neither is any non-npm manifest: a Python, Cargo, Go, RubyGems, Composer or NuGet project produces an SBOM with no components from that ecosystem. Every such file that is present is named in the document, in metadata.properties, alongside an inventory-coverage value of full-transitive, direct-only or none, so an inventory that was never taken is never mistaken for a product that ships nothing. The scanner's threat detection covers all the ecosystems listed at the top of this README; only the SBOM inventory is npm-scoped.
• Dependency risk: detects known-malicious packages and versions, typosquatting, dependency confusion, and compromised publisher activity, at scan time and at install time.
• Supply chain integrity: grades SLSA provenance from levels 0 to 3 by parsing and structurally validating in-toto/DSSE attestations, giving a recorded integrity signal per project.

# Write a CycloneDX 1.6 SBOM alongside the scan report
supply-chain-guard scan ./project --sbom-output sbom.json

--sbom-output <file> and --format sbom produce the SAME document for the same scan: the same components, the same dependency graph, the same vulnerabilities entries and the same incident annotations. Only the serialNumber and the timestamps differ, because each invocation is its own run. The two exist so an SBOM can be written to a file while the scan report itself goes to stdout in another format.

What the SBOM carries, and what it says it could not assess

From package-lock.json (v2 or later) every component carries a stable bom-ref, a purl, the integrity hashes, the CycloneDX scope, and the licence the lockfile declares, expressed as an SPDX expression when the string is an expression and as license.id when it is a plain SPDX identifier. An identifier the generator cannot vouch for is kept as license.name rather than asserted as SPDX, because the CycloneDX schema constrains license.id to the SPDX enum. Relationships are emitted as a top level dependencies array rooted at the subject component and resolved the way npm resolves them, so a nested duplicate is linked to the dependent that actually installed it rather than to the hoisted copy.

What could not be assessed is stated instead of left blank. A component whose manifest declares no licence carries a supply-chain-guard:license property saying so, so an empty licence column is never read as "no licence terms". At the document level, metadata.properties records which manifest the inventory came from, how many components carry a declared licence, whether the dependency graph was resolved, partial or not assessed, and how many declared edges resolve to no component in the document (uninstalled optional peer dependencies, normally). A declared edge whose target is not in the document is counted there rather than emitted as a dependsOn pointing at a bom-ref that does not exist.

# What this SBOM says it could and could not assess
supply-chain-guard scan ./project --format sbom > sbom.json
node -e "const d=require('./sbom.json');for (const p of d.metadata.properties ?? []) console.log(p.name, '=', p.value)"

Findings removed by a suppress: entry in .supply-chain-guard.yml are emitted as CycloneDX VEX statements, with the reason the policy declared carried verbatim in analysis.detail. No analysis.justification is emitted: that field is a fixed enum that a free-text reason cannot be mapped to. A suppression with no recorded reason produces a statement that says exactly that.

Component hashes are hexadecimal digests, decoded from the base64 Subresource Integrity value npm writes into the lockfile, because that is the encoding the CycloneDX hash-content pattern requires. An integrity part whose algorithm is not one this generator maps, or whose payload does not decode to the digest length its algorithm requires, is dropped and reported on the component rather than emitted, and counted at the document level. purls are canonical: the npm scope is the purl namespace and the separator after it is a literal /.

Where the inventory came from package.json because no lockfile was present, a component carries version and purl only when the manifest declares one exact version. A range, a dist-tag such as latest, a git or URL specifier and a workspace: protocol are constraints, not versions: those components carry neither field, a supply-chain-guard:version property records why, and supply-chain-guard:declared-specifier keeps the declared string verbatim.

Supplier and author are not emitted. package-lock.json does not carry either field, and the SBOM generator reads only package-lock.json and package.json, so there is nothing to populate them from without a registry lookup.

Article and paragraph citations are deliberately omitted here. Map these outputs to specific provisions against the final published regulation text, with your own legal review, rather than against this README.

NIS2 Directive

NIS2 requires essential and important entities to take measures covering supply chain security. The relevant capabilities are:

• Supply chain risk: typosquatting, dependency confusion, compromised packages, and malicious GitHub Actions in CI/CD workflows.
• Incident evidence: the correlation engine links individual findings into named attack chains with confidence scores calibrated to indicator match completeness. The incident record itself, with its name, confidence, indicator counts (matched and total), list and narrative, is carried by three formats: JSON (incidents on the report), SARIF (the incident list on runs[0].properties, and the incidents each result belongs to in that result's property bag) and CycloneDX (one annotations entry per incident, whose subjects are the vulnerabilities entries it groups). The text renderer prints it as a panel. The markdown, HTML, badge, GitLab and JUnit formats carry the individual findings only, not the incident record. For a ready-made evidence document rather than a machine format, scan --export-incident-md writes a markdown incident report to stdout: risk score, every detected incident with its confidence, narrative and indicator list, the critical findings, and the response playbooks.
• Configuration exposure: IaC, Dockerfile, and .npmrc / .yarnrc scanning surfaces misconfiguration before deployment.

Operating model

Apache-2.0, no account required, and no telemetry: the scanner reports only to its own output.

Offline by default: scan on a local path runs fully offline (unless one of the opt-in flags --check-registry or --external-intel is passed), as do guard, feed stats, feed import, and all report formatters. These commands make zero network requests and are suitable for air-gapped and data-egress-restricted environments.

An offline scan matches against the bundled indicator set: every domain, URL, IP and hash, every curated campaign, and the recent package indicators. Older package indicators live in the historical catalog, which is much larger than the bundle and is downloaded by supply-chain-guard feed refresh into the per-user cache directory (see Catalog cache). A scan without that cache, or with one left over from another release, runs against the bundled set only, and every scan report says so in its Catalog line (see THREAT_FEED_CATALOG_MISSING).

Networked commands and external disclosures: The commands that reach the network do so deliberately for their specific functions:

• supply-chain-guard npm <pkg> / pypi <pkg> / vscode <ext>: fetch and inspect remote packages and extensions from public registries (npm, PyPI, VS Code Marketplace, Open VSX).
• supply-chain-guard confusion <dir>: inspects project dependency manifests and transmits every declared dependency and devDependency package name to the public npm and PyPI registries to determine whether private or internal packages are registered publicly.
• supply-chain-guard repo <url> and supply-chain-guard org <name>: inspect remote GitHub repositories and organizations by invoking the gh CLI as a child process, using the caller's ambient GitHub credentials.
• supply-chain-guard monitor <wallet>: polls public Solana RPC nodes for C2 wallet transaction activity.
• supply-chain-guard feed refresh: downloads updated threat intelligence from the project's daily channel on GitHub Pages into the local cache (hosts: homeofe.github.io, with fallback to github.com, release-assets.githubusercontent.com and api.github.com). --no-catalog downloads the feed alone.
• supply-chain-guard scan <github-url>: clones a remote repository via Git for analysis.
• supply-chain-guard scan . --check-registry: opt-in flag that queries the public npm registry for the package's latest published version to detect version drift, and transmits each Python dependency name from requirements.txt / pyproject.toml to the public PyPI registry for dependency-confusion signals. Up to v6.2.5 the PyPI lookups ran on every scan of a Python project, contrary to the offline guarantee above; they now need this flag.
• supply-chain-guard scan . --external-intel: opt-in flag for the two-tier score. It sends each dependency's name, ecosystem and version to the OSV API, the CVE ids found to FIRST's EPSS API, and the project's GitHub owner/repo to the OpenSSF Scorecard API, and downloads the public CISA KEV catalog.

Offline runs use the feed bundled with the installed version, so pin the version you intend to audit against. To keep an offline network on the daily feed, see Air-gapped networks.

Air-gapped networks

The signed daily feed can be carried into a network without internet access and installed there with the same checks feed refresh applies (signature against the key compiled into the package, rollback and size guards, the catalog's digest chain), without any network request.

1. On a connected machine, download both files of the daily channel and check the archive (--ignore-missing is GNU coreutils; on macOS compare shasum -a 256 feed-offline.tar.gz with its line in SHA256SUMS):

curl -fLO https://homeofe.github.io/supply-chain-guard/feed/feed-offline.tar.gz
curl -fLO https://homeofe.github.io/supply-chain-guard/feed/SHA256SUMS
sha256sum -c SHA256SUMS --ignore-missing

1. Once per upgrade, also download the installed version's catalog-index.json and catalog-*.json.gz from its GitHub Release, for the historical catalog.
2. Carry the files across, unpack the archive into a new directory, put the catalog files beside it, and import:

mkdir scg-feed && tar -xzf feed-offline.tar.gz -C scg-feed
mv catalog-index.json catalog-*.json.gz scg-feed/   # after an upgrade only
supply-chain-guard feed import ./scg-feed

With the Docker image, mount the directory and the cache volume: docker run --rm -v scg-cache:/cache -v "$PWD/scg-feed:/import:ro" ghcr.io/homeofe/supply-chain-guard@sha256:<digest> feed import /import.

A feed whose signature does not verify, that is older than the installed one, or that is truncated is refused, and the previous cache stays in place. After an upgrade, carry an archive published after that release: an older one is refused as older than the bundled feed, and the catalog is not installed either. Install the npm package itself from an internal registry or mirror, and pin the Docker image by digest (ghcr.io/homeofe/supply-chain-guard@sha256:...) rather than by tag. If you run the scanner offline, please describe your setup in the repository's GitHub Discussions, so the offline path can be shaped by real use.

GitHub Action

Pin an exact version. That is the recommended form, and it is the same advice this tool gives about your own dependencies: a security scanner should be a deterministic input, so you know which detection logic and which IOC feed ran, and an upgrade is a reviewable change rather than something that happens to you.

name: Supply Chain Security
on: [push, pull_request]

permissions:
  contents: read
  pull-requests: write

jobs:
  scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: homeofe/supply-chain-guard@v6.6.0
        with:
          fail-on: critical
          comment-on-pr: true

Let Dependabot keep the pin current:

# .github/dependabot.yml
version: 2
updates:
  - package-ecosystem: github-actions
    directory: "/"
    schedule:
      interval: daily

Threat data does not wait for the pin. Since 6.6.0 the Action installs the signed daily feed and the catalog on every run (refresh-feed and refresh-catalog, both on by default), so new malicious packages reach your scans the day they are published, whatever version you pin. The pin decides the scanner's code and rules, which this project releases about once a week (security fixes at once). A daily Dependabot interval still tracks that best: in the 155 days to 2026-08-21 releases came about 1.4 a day, and a weekly schedule then closed every bump pull request as superseded before anyone merged it, so the pin never moved (measured in one consumer: eight weekly pull requests in a row, and the pin 82 releases behind).

The interval is the cheap half. The half that actually decides the outcome is whether somebody merges the pull request, and no setting in this file supplies that.

@v6, and what it does and does not guarantee

@v6 also works and stays supported. It is a floating branch, fast-forwarded to each release by CI, and the composite action on it pins an exact npm version that is bumped and build-gated on every release. So @v6 is not latest: every resolution still installs one exact, release-gated version.

The caveat is what happens after a major. If the v6 line stops being released once v7 ships, @v6 keeps resolving a frozen action that pins an old npm version, and the IOC feed it installs stops updating. For a scanner that is a silent false-negative generator, and nothing in your workflow would report it. An exact pin is what turns that into a reviewable out-of-date dependency instead.

Be precise about what an exact pin does and does not buy you, because a frozen exact pin is the same silent false negative. It ages exactly as quietly. The daily feed keeps the package indicators current (unless refresh-feed: false), but the detection rules, heuristics and matchers are those of the pinned version, so a pin that stops moving freezes them at that date. What an exact pin buys is a place where the staleness becomes reviewable: the bump pull request. That is a different claim from the staleness being visible on its own, and the measurement above is what the difference costs. If those pull requests are opened and superseded without ever being merged, the pin is frozen and the rule set is ageing.

The scan itself now says so. Every scan measures how old the rule set it just matched against actually is, and reports THREAT_FEED_STALE (medium) once the newest indicator in that rule set is more than 30 days old. The finding carries the measured age and the newest indicator's date, it raises the risk score off zero and the risk level off clean, and it is named in eight of the nine report formats and in the Action's pull request comment, which renders whichever format you set (markdown by default). It is derived offline from the feed itself, so it travels with the pin: an installation that never updates reports its own age without needing a network call, a registry lookup, or anything configured by the consumer.

Where it appears, exactly, because "every format" would be one format too many: text, json, markdown, sarif, sbom, html, gitlab and junit all carry the rule id THREAT_FEED_STALE, and all but junit carry the full description as well. The ninth format, badge, does not: the Shields.io endpoint payload is {schemaVersion, label, message, color} derived from the findings summary counts, so it never names a rule. What you see there instead is the badge for an otherwise clean repository turning from clean/brightgreen into 1 medium/yellow - the condition is visible, but not identifiable, and a badge is the one surface where that matters least. In junit the rule id is a passing <testcase> rather than a <failure>, because only critical and high become failures there.

The measurement is taken over the rule set the scan used, not over the version number. A consumer running supply-chain-guard feed refresh daily (the GitHub Action does it on every run) scans with the published daily feed and is correctly reported as current even on an old pin. supply-chain-guard feed stats prints both ages side by side, the one bundled with the installed version and the effective one at scan time, so the two are never confused. If a deliberately frozen rule set is the intent, exclude the rule by name:

- uses: homeofe/supply-chain-guard@v6.6.0
  with:
    exclude-rules: THREAT_FEED_STALE

THREAT_FEED_CATALOG_MISSING

Staleness is about the rule set being old. This one is about part of it not being consulted at all.

The indicator corpus is published in two pieces. Recent and curated indicators are compiled into the package and always available offline. The historical corpus lives in a catalog that is published beside the release and downloaded on demand, because carrying all of it in the package would make every install and every Action run pay for indicators most scans never match. A scan without the catalog is narrower than a scan with it, and without this rule it reports exactly the same success.

supply-chain-guard feed refresh downloads the catalog and caches it for later scans, in the per-user cache directory unless --cache-dir or SCG_CACHE_DIR names another (see Catalog cache). The cache belongs to one release, so an upgrade needs a new refresh.

A catalog that was never downloaded is the ordinary state of a fresh install, so it stays an informational note and does not mark the scan partial. A catalog that IS on disk but cannot be used (unreadable or truncated, or not matching the digest this release pins) is reported as THREAT_FEED_CATALOG_UNAVAILABLE instead: the scan is marked partial and exits non-zero, because the historical indicators were silently not consulted. Run supply-chain-guard feed refresh to replace it. A catalog that feed refresh installed for this release and that has since been deleted counts the same way: the refresh leaves a small catalog-installed.json marker beside it, and a missing catalog with that marker present is THREAT_FEED_CATALOG_UNAVAILABLE (high, partial), not a fresh install. The marker only ever raises the finding; a missing, malformed or older-release marker reads as never installed. catalog: required raises both rules to critical.

Catalog cache

feed refresh and every scan resolve the same directory, in this order:

1. --cache-dir <dir>
2. the SCG_CACHE_DIR environment variable
3. the per-user cache directory: %LOCALAPPDATA%\supply-chain-guard\cache on Windows, ~/Library/Caches/supply-chain-guard on macOS, and $XDG_CACHE_HOME/supply-chain-guard or ~/.cache/supply-chain-guard elsewhere

The working directory is not used, so one refresh serves scans started from any directory, and a scanned checkout cannot supply its own cache. A .scg-cache directory left in the working directory by earlier releases is no longer read; the catalog finding says so when one is present. Pass --cache-dir .scg-cache to keep using it, or refresh once. Reports name a cache under the home directory as ~/..., without the account name.

Upgrading from 6.3.x or earlier. Before 6.4.0 a refresh wrote .scg-cache/threat-feed.json in the working directory. A pipeline step that refreshes and then checks that file fails after the upgrade although the refresh succeeded, because the file is now written to the per-user directory. Set the directory on that step, for example in a GitHub Actions step:

env:
  SCG_CACHE_DIR: .scg-cache

feed refresh and feed stats both honour it. feed refresh prints a note when it finds a .scg-cache in the working directory that it did not write. The finding names how many historical indicators were not consulted and why, and the reason matters:

The last two are not normal states. They say the scanner's own detection data is either corrupt or has been modified in place, which is a different problem from "not downloaded yet" and is worth looking at the machine for.

"Not downloaded yet" is info so that it does not turn every first run yellow, and that also means --min-severity low, the Action's default, filters the finding out. The same state is therefore recorded as provenance, independent of any severity filter:

• every scan report carries a Catalog line in every format, in bold in the Markdown report (and so in the Action's pull request comment whenever one is posted) when the catalog was not consulted. The npm, pypi and vscode commands, which vet one remote package, carry no Catalog line;
• JSON and SARIF carry detectionSet.catalog (consulted, entryCount, reason), and the CycloneDX SBOM carries supply-chain-guard:detection-set:catalog-consulted;
• the MCP ioc_lookup result carries checkedAgainst.catalog, plus a coverageNote on a clean package verdict reached without the catalog.

None of these changes the score, the risk level, the badge or the exit code.

The cache checksum is also compared with an entries digest compiled into the package. A cache with the right public header, recomputed checksum and entry count is still refused when its actual indicators differ from this release.

Set catalog: required in .supply-chain-guard.yml to treat any of them as critical, so a scan that could not consult the full corpus fails the default gate rather than reporting a narrower result as success:

catalog: required

The GitHub Action installs the daily feed and the catalog by default (refresh-feed and refresh-catalog). It caches into an isolated directory under RUNNER_TEMP, not into the checkout, so a preceding feed refresh in the workflow does not count, and catalog: required on the Action needs both inputs left on (the default), or explicitly:

- uses: homeofe/supply-chain-guard@v6.6.0
  with:
    refresh-catalog: true

An empty catalog is a valid catalog: while a release publishes no historical indicators there is nothing to miss, and the rule stays quiet under the default setting rather than firing on every scan. If scanning against the bundled set alone is the intent, exclude the rule by name:

- uses: homeofe/supply-chain-guard@v6.6.0
  with:
    exclude-rules: THREAT_FEED_CATALOG_MISSING

How the Action installs the scanner it runs

The Action does not trust the registry to hand it the right scanner. The npm version is pinned in action.yml, and that alone would let a registry or CDN response carrying other bytes under that version run as the scanner, next to your checkout and your token. So before anything is scanned:

1. The pinned version is installed into a throwaway project under RUNNER_TEMP, from https://registry.npmjs.org/, with --ignore-scripts, never globally. Its lockfile records the integrity of the tarball on disk.
2. npm audit signatures --include-attestations verifies the registry signature and the Sigstore provenance of what was installed.
3. scripts/verify-action-install.mjs then requires what npm does not: that the provenance exists at all, that its signing certificate was issued to this repository (by name and by numeric id) running .github/workflows/ci.yml at the release tag, and that it describes the tarball the lockfile recorded.

Any failure stops the job with an error annotation naming the check, before the scan step runs and before the scanner reaches PATH. No input changes this and the inputs and outputs are unchanged.

What this covers is the scanner package itself. Its npm dependencies (today one, commander, resolved within its declared range at install time) are checked by registry signature only: they carry no provenance from this repository, and the published package ships no shrinkwrap that would pin them.

Two operational requirements follow. The runner needs npm 11.12.0 or later, which Node 24.15.0 and later bundle. The Action's actions/setup-node step uses check-latest: true, so a runner whose tool cache holds an older Node 24 resolves the newest 24.x instead; if npm is still too old after that, the install step fails closed with a message saying so. And the step talks to registry.npmjs.org and to the Sigstore trust root CDN (tuf-repo-cdn.sigstore.dev). The public registry is set explicitly, whatever a runner's .npmrc says, because the provenance check is only meaningful against the registry that recorded the attestation; a runner that can reach only a registry mirror cannot verify the scanner and will not run it.

Action Inputs

Coverage failures are fail-closed regardless of fail-on: the Action exits nonzero, sets partial-scan to true and risk-level to partial, and posts a warning even when severity filters hide the informational coverage finding. A critical threshold failure retains exit code 2; other partial results exit 1.

PR comments require pull-requests: write (shown above). GitHub restricts write access for pull requests from forks, so the check verdict, job log, and outputs remain authoritative when the platform refuses a comment.

Action Outputs

For AI Coding Agents (MCP)

supply-chain-guard is both a scanner OF the agentic ecosystem and a tool FOR it.

Scanning agentic attack surfaces (automatic in every scan):

• MCP server configs: .mcp.json, .cursor/mcp.json, .vscode/mcp.json, claude_desktop_config.json - malicious server packages, C2 endpoints, plain-http servers, secrets forwarded to remote servers, prompt injection in tool descriptions (MCP_ rules)
• Agent skills and rules files: .claude/skills/**/SKILL.md, .claude/settings.json hooks, .cursorrules, .github/copilot-instructions.md, AGENTS.md, CLAUDE.md - injected control tokens, invisible Unicode instruction channels, download-and-execute and credential-harvesting instructions, dangerous hook commands (SKILL_/AGENT_ rules)

Built-in MCP server - let your AI agent vet packages BEFORE installing them:

npm install -g supply-chain-guard
claude mcp add supply-chain-guard supply-chain-guard mcp

This form works in every shell (bash, zsh, PowerShell, cmd) and avoids npx cold-start timeouts on first connect. On bash/zsh you can use the one-liner claude mcp add supply-chain-guard -- npx -y supply-chain-guard mcp instead; note that PowerShell swallows the bare -- itself, so on Windows prefer the global-install form above. The agent host starts the server in its own working directory, usually the workspace; if that workspace is not trusted, npx lets npm run files from it (GHSA-gqpg-9mjx-pv4w), so the global install is the safer form there too.

Exposes three tools over stdio: ioc_lookup (offline IOC + known-bad-version check for every supported ecosystem; package verdicts include the historical catalog only after feed refresh, and the result says which), scan_directory, and scan_npm_package. Client config snippets for Claude Code, Claude Desktop, and Cursor: docs/mcp.md.

Live Threat Feed

The bundled IOC feed ships with every release. A signed feed is also published every day, without a release, on the project's GitHub Pages channel, so new indicators reach feed refresh the day the advisory sources publish them:

supply-chain-guard feed stats     # entry counts by type and severity, plus rule-set age
supply-chain-guard feed refresh   # pull the latest published feed into the local cache
supply-chain-guard feed osv       # export malicious-package IOCs as OSV records

A refreshed feed is merged into every later scan until the next refresh replaces it; after 24 hours feed stats and the scan report mark a refresh as due.

Daily channel and fallback: the default source is the daily channel, https://homeofe.github.io/supply-chain-guard/feed/feed.json. When it cannot be installed for any reason, feed refresh falls back to the feed.json attached to the latest GitHub Release, with the same checks, and says which source it installed. The daily feed is the reviewed feed of the main branch, plus the exact-version pins whose version an advisory source names and file hashes, which are published the same day without review; everything that could block a legitimate package (package names, version ranges, domains) is reviewed on the main branch first and is in the next day's feed after that. An indicator built into an installed version can only be removed by a release (design). When the cache is already newer than both sources, feed refresh keeps it and reports it current.

Feed integrity: both sources publish feed.json.sig beside the feed, an Ed25519 signature over its exact bytes, made by the same key. feed refresh verifies it against the public key compiled into the installed package (fingerprint in SECURITY.md) before parsing anything, and refuses a missing, malformed or wrong signature with a non-zero exit, leaving the previous cache in place. The signed bytes and signature are kept beside the cache and checked again on every scan, so a cache edited or planted afterwards is reported as THREAT_FEED_CACHE_UNREADABLE and the scan is partial.

A self-hosted mirror passed with --url must serve feed.json.sig next to the feed, signed by the same key. A mirror that cannot be signed can be accepted explicitly with feed refresh --url <url> --allow-unsigned-feed; that prints a warning, records in the cache that the feed was not verified, and trusts the feed as downloaded. There is no environment variable for it. A mirror never falls back to the built-in sources, and the catalog is read from the mirror too.

Rule-set age: feed stats reports two ages, the one bundled with the installed version and the effective one at scan time, and marks either [STALE] past 30 days. --format json returns the same values as bundledFreshness and freshness (newestIndicator, ageDays, datedEntries, stale) for a workflow that wants to assert on them directly. Both are computed offline, from the feed itself.

OSV export: feed osv emits the feed's malicious-package indicators (npm, PyPI-adjacent, Go, RubyGems, Packagist, crates.io, NuGet) as OSV-schema records, so the feed is consumable by osv-scanner and other OSV-native tooling:

supply-chain-guard feed osv --out malicious.osv.json

Indicator contract: every feed value is a LITERAL indicator (a domain, IP, URL, hash, or package name), never a regular expression. All ingestion paths (feed refresh, the legacy update API, and the cached-feed load at scan time) validate each entry against its type's shape and quarantine anything invalid - a malformed or hostile feed entry can neither crash a scan nor flood it with garbage matches, and a rejected refresh never overwrites the previous cache.

Acquisition bounds: both download paths are bounded before anything is parsed or written. An absolute 30 second deadline covers DNS, connect, headers and the body read; the response is capped at 32 MiB, refused on a declared Content-Length over the cap before a byte is read and counted again while streaming when no length is declared; at most 5 redirects are followed and every hop is revalidated. An inactivity timeout would not be enough, because a peer that keeps trickling bytes never triggers one. Every bound fails closed and loudly: the download is abandoned, one line naming the bound goes to stderr, the command exits non-zero, and the previous cache stays in effect.

Where the feed comes from

Curated entries are hand-added from vendor write-ups. Malicious-package entries are additionally discovered through three public upstream sources, with no account and no API key:

• GitHub Advisory Database - malware advisories (CWE-506), one discovery source. Licensed CC BY 4.0; every imported entry carries its GHSA-... id in its source field.
• OpenSSF malicious-packages - independent discovery through OSV's incremental MAL- record exports. These records aggregate origins including ecosystem analysis services and security vendors, while retaining the original providers in every imported entry. Licensed Apache-2.0.
• DataDog malicious-software-packages-dataset - npm and PyPI packages DataDog confirmed as malicious, read in full on every run. Only versions the dataset holds a malware sample for are pinned; a whole-package verdict becomes a name block only when the registry has already removed the package and no other source limits that name to specific versions. Licensed Apache-2.0; every imported entry carries datadog-malicious-packages in its source field.

OSV querybatch separately corroborates GitHub-discovered packages. It is never used to corroborate an OpenSSF-discovered package against the same database.

npm run feed:import -- --dry-run   # what the next refresh would add
npm run feed:import                # import, then regenerate feed.json

Every imported entry is auditable: the source field names the public advisory it came from. A failed import writes nothing at all - the previous feed stays in effect and the process exits non-zero. The full mapping (ecosystem prefixes, version-range rules, which upstream fields deliberately stay unset) is in docs/threat-feed-sources.md; the source-adapter contract and trust boundaries are in docs/feed-architecture.md.

Install Guard

Block known-bad packages BEFORE the package manager runs their lifecycle scripts - the only install blocker whose entire blocklist is auditable in git history, offline, no account:

supply-chain-guard guard npm install lodash        # clean: npm runs normally
supply-chain-guard guard pnpm add axios@1.14.1     # known-bad: blocked, exit 2

Supports npm, pnpm, yarn, and bun. Guard flags go BEFORE the manager name: --dry-run checks the command without ever invoking the manager, --force proceeds despite findings (with a loud warning). Everything after the manager name is passed through to it unchanged.

All checks are offline against the bundled IOC feed (plus a feed refresh cache when present), the known-bad-version blocklist, and the typosquat heuristics - no network call, no telemetry.

Limitation: version ranges and tags (^1.2.3, latest) are not resolved offline, so a version-pinned IOC only fires on an exact pin. Bare-name IOCs (a whole malicious package) fire on any version. Use scan after install for full-tree, behavior-level coverage.

Adding Custom Patterns

Edit src/patterns.ts to add new detection rules:

{
  name: "my-custom-pattern",
  pattern: "regex-pattern-here",
  description: "What this detects",
  severity: "high",
  rule: "MY_CUSTOM_RULE",
}

Architecture

scan() -> collectFiles() -> per-file analysis
  -> Pattern matching (350+ rules across 12 categories)
  -> Entropy analysis (Shannon entropy for encoded payloads)
  -> IOC blocklist check (known C2 domains, IPs, hashes)
  -> Internal-disclosure family (private addresses, internal hostnames,
     non-public forge URLs, developer paths, configured deny-list)
  -> Install hook deep analysis (secret harvesting, download-exec)
  -> Dependency risk analysis (Levenshtein typosquatting)
  -> Sub-scanners (lockfile, GitHub Actions, Docker, Cargo, Go, IaC)
  -> SLSA verifier (provenance level 0-3, sigstore/cosign, attestations)
  -> SBOM generator (reads package-lock.json → real CycloneDX 1.6 components)
  -> GitHub trust signal analysis (account age, stars, releases)
  -> Correlation engine (links findings into incidents)
  -> Trust breakdown (4-dimension scoring)
  -> Report generation (text/json/html/markdown/sarif/sbom)

Show that you scan

If supply-chain-guard runs in your CI, add the badge to your README:

[![scanned by supply-chain-guard](https://img.shields.io/badge/scanned%20by-supply--chain--guard-2ea44f?logo=npm&logoColor=white)](https://github.com/homeofe/supply-chain-guard)

A static badge only claims the scan. To make it prove one, point it at the status of the workflow that runs the scan, the way this repository's own badge shows its self-scan:

[![scanned by supply-chain-guard](https://github.com/OWNER/REPO/actions/workflows/supply-chain-guard.yml/badge.svg?branch=main)](https://github.com/OWNER/REPO/actions/workflows/supply-chain-guard.yml)

Contributing

See CONTRIBUTING.md for guidelines. The most impactful contribution is adding new detection patterns for emerging threats.

Changelog

Full release history lives in CHANGELOG.md.

License

Apache-2.0 - Copyright 2026 Elvatis - Emre Kohler