supply-chain-guard

Open-source supply-chain security scanner for npm, PyPI, Cargo, Go, RubyGems, Composer, NuGet, Docker, Terraform, VS Code extensions, GitHub Actions and GitHub repositories. Detects malware campaigns (GlassWorm, Vidar, Shai-Hulud), fake AI tool repos, account takeovers, and 350+ threat indicators across all major lockfile formats (npm, pnpm, yarn, bun). 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.

Contents

• Background
• What It Detects
• Installation
• Quickstart
• Output Formats
• CI Exit Code Control
• Filtering
• Internal Disclosure
• Policy Configuration
• Baseline Diffing
• Example Output
• Supported Ecosystems
• 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

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

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: curl pipe, base images on a moving channel tag or without a digest, hardcoded secrets, SUID bits. Compose image: values are out of scope for every Docker rule (see docs/ARCHITECTURE.md)
• Terraform/IaC: inline scripts, external modules, hardcoded secrets
• 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:

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: v6.0.18
    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:6.0.18 scan /scan

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

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

# Scan with registry version-drift check (requires network)
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

# 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][email protected]"
  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

| Rule | Severity | Shape | |---|---|---| | INTERNAL_PRIVATE_IP | medium | RFC1918 (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), CGNAT (100.64.0.0/10), link-local (169.254.0.0/16) | | INTERNAL_PRIVATE_IPV6 | medium | IPv6 Unique Local Addresses (fc00::/7) | | INTERNAL_HOSTNAME | medium | Hostnames in an internal-only TLD: .internal, .local, .lan, .corp, .home, .intranet | | INTERNAL_SERVICE_ENDPOINT | medium | http(s)://HOST:PORT where HOST is private or internal | | INTERNAL_GIT_REMOTE | medium | ssh://git@<host>:<port>/<path> and scp-style git@<host>:<path> where the host is not a known public forge | | INTERNAL_DEV_PATH | medium | C:\Users\<name>\, /home/<name>/, /Users/<name>/ in committed code or docs. /Users/ is matched case-sensitively, because /users/ is a REST route | | INTERNAL_SINGLE_LABEL_URL | low | A URL whose host has no domain at all, so it only resolves through internal DNS or a hosts file | | INTERNAL_DENYLIST_MATCH | medium | A term your project configured (see below). Off unless configured | | INTERNAL_DISCLOSURE_TRUNCATED | info | A limit stopped this family short on one file (see Bounded cost). Never silent about a gap |

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 [email protected]:... 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.

| Surface | Rules that still fire | |---|---| | Source files (.ts, .py, .tf, .yml, Dockerfile, .npmrc, lockfiles) | all of them | | Documentation prose and fenced code blocks: .md / .rst / .txt, anything under docs/ | everything except the single-label URL | | Markdown inline code spans, and fenced blocks tagged ```text / ```plaintext | hostname, endpoint, clone URL | | Files that exist to BE an example: examples/, samples/, fixtures/, testdata/, *.example.* / *.sample.* / *.template.* | hostname, endpoint, clone URL | | Test, spec, mock and fixture files and directories (test/, tests/, spec/, e2e/, __tests__/, __mocks__/, *.test.*), minified and bundled output | none |

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

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 refused when it quantifies a group that already contains a variable quantifier ((a+)+, (a?)*, and the like). That shape can take exponential time to report no match, so one committed line would otherwise occupy a runner until the workflow times out.
• 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).

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

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.

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.

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       │
│                                                                              │
└──────────────────────────────────────────────────────────────────────────────┘

Supported Ecosystems

| Ecosystem | Command | What It Scans | |-----------|---------|---------------| | npm | scan, npm | package.json, install scripts, tarball; lockfiles: package-lock.json, pnpm-lock.yaml, yarn.lock (v1 + Berry), bun.lock | | PyPI | pypi | setup.py, setup.cfg, pyproject.toml, install hooks | | Cargo/Rust | scan | Cargo.toml, build.rs, proc macros | | Go | scan | go.mod, init() functions, CGo, plugin loading | | RubyGems | scan | Gemfile, Gemfile.lock (malicious-gem IOCs, http/git sources) | | Composer/PHP | scan | composer.json, composer.lock (malicious-package IOCs, http repos) | | NuGet/.NET | scan | packages.lock.json, .csproj, nuget.config (malicious-package IOCs, http feeds) | | Docker | scan | Dockerfile, Dockerfile., Containerfile. docker-compose.yml is read, but every Docker rule is anchored on a Dockerfile instruction keyword, so Compose image: values are not covered | | Terraform | scan | .tf, .hcl files (provisioners, modules, secrets) | | VS Code | vscode | .vsix files, activation events, dangerous APIs | | GitHub Actions | scan | .github/workflows/*.yml | | GitHub Repos | repo | Trust signals, releases, README lures | | Solana | monitor | C2 wallet memo transactions |

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.

| Tool | Focus | Malware / behavior detection | Known-CVE lookup | Ecosystems | Open source | Account needed | |---|---|---|---|---|---|---| | supply-chain-guard | Malware campaigns, IOCs, behavior heuristics in installed artifacts; SBOM + SLSA provenance grading (in-toto/DSSE structural validation) | Yes: 350+ static heuristics plus multi-source GHSA/OpenSSF package verdicts and campaign-IOC matching, fully local/offline at scan time | No | npm (incl. pnpm/yarn/bun lockfiles), PyPI, Cargo, Go, RubyGems, Composer, NuGet, Docker, Terraform/IaC, VS Code extensions, GitHub Actions, GitHub repos | Yes (Apache-2.0) | No | | OSV-Scanner | Known vulnerabilities in dependency inventories (OSV.dev database lookup) | Known-malicious versions via OSV MAL- entries only; no behavior or IOC analysis | Yes (offline mode available) | 11+ ecosystems, 19+ lockfile formats, container images, SBOM input | Yes (Apache-2.0) | No | | Socket | Proactive behavioral analysis of entire registries (SaaS) | Yes: 70+ risk types registry-wide, before advisories exist; engine is closed source and cloud-side | Yes | npm, PyPI, Maven, Go, Cargo, RubyGems, NuGet, more; Actions workflows | CLI only (MIT); detection engine proprietary | Yes (except Firewall Free) | | GuardDog | Heuristic 0-10 risk scoring of individual packages (YARA + registry metadata) | Yes: heuristics only, no known-malware or campaign-IOC database; sandboxed scanning | No | npm, PyPI, Go, RubyGems, GitHub Actions, VS Code extensions | Yes (Apache-2.0) | No | | OpenSSF Scorecard | Security-practice score of upstream repos (branch protection, pinning, review) | No: rates project hygiene, never analyzes published package contents | Only for the rated repo itself (OSV check) | GitHub repos, partial GitLab | Yes (Apache-2.0) | No (GitHub token for self-run CLI) | | npm audit | Advisory lookup for your npm dependency tree, built into npm | Known-malicious versions after an advisory is published; no behavior or IOC analysis; audit signatures verifies provenance | Yes (GitHub Advisory Database) | npm only | Yes (CLI; lookup is a registry-side service) | No |

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 . 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 against the bundled threat feed (unless the opt-in --check-registry flag is passed), as do guard, feed stats, and all report formatters. These commands make zero network requests and are suitable for air-gapped and data-egress-restricted environments.

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 upstream repository into the local cache.
• 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.

Offline runs use the feed bundled with the installed version, so pin the version you intend to audit against.

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/[email protected]
        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

daily, not weekly, and this project's release rate is why. Measured over the 155 days to 2026-08-21: 134 releases, about 1.4 a day over the last two months, with a median of 20 hours between releases and two thirds of the gaps under a day. A weekly schedule cannot track that. Each weekly run opens a correct bump pull request, and the next weekly run closes it as superseded and opens another, so an unattended pin never moves at all. Measured in one consumer of this Action: eight consecutive weekly bump pull requests, each alive for exactly seven days, each proposing a newer target than the last, while the pin itself sat unchanged for 49 days and fell 82 releases behind. Every scan check was green throughout, because a stale pin is not a failing scan.

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. This scanner runs offline against the IOC feed bundled with the pinned version, so a pin that stops moving freezes the detection rules 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 before each scan merges the published feed for 24 hours 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/[email protected]
  with:
    exclude-rules: THREAT_FEED_STALE

Action Inputs

| Input | Description | Default | |-------|-------------|---------| | path | Path to scan | . | | format | Output format (text/json/markdown/sarif/sbom/html/badge/gitlab/junit) | markdown | | min-severity | Minimum severity to report | low | | exclude-rules | Comma-separated rule IDs to exclude | | | fail-on | Fail check at this severity or above, including info | critical | | comment-on-pr | Post or update a PR comment | true |

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

| Output | Description | |--------|-------------| | score | Risk score from 0 to 100 | | risk-level | partial, clean, low, medium, high, or critical | | findings-count | Number of reportable findings after filters | | partial-scan | true when coverage was incomplete | | report | Requested report, or a size notice when it exceeds the safe output budget | | report-path | Runner-local path to the complete report for later steps in the same job | | report-truncated | true when report was replaced by the size notice |

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