Web App Security Skill

Version updated for https://github.com/parousia8888/web-app-security-skill to version v0.5.3.

  • This action is used across all versions by 0 repositories.

Action Type

This is a Composite action.

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Action Summary

This GitHub Action automates web application security audits by leveraging AI coding agents. It helps identify potential security vulnerabilities in local source files without requiring offensive-security expertise. The action reads project files locally, generates reports with explanations and evidence, and provides reviewable changes to enhance security and test the product’s normal behavior.

What’s Changed

Web App Security Skill v0.5.3

Web App Security Skill gives Web builders using AI coding agents a reviewable local security first pass. Run it without installing:

npx --yes web-app-security-skill@0.5.3 audit . --fail-on never

The report explains each lead in security terms and ordinary language, states what the evidence does not prove, proposes a change for review, names likely product side effects, and separates security retesting from normal-behavior testing. The command does not edit the project or contact a deployment.

v0.5.3 also includes the Claude repository plugin, diff-scoped review, the planted pattern benchmark and public known limitations. These are bounded first-pass capabilities; they do not prove that a project is secure or establish production-vulnerability precision or recall.

Release identity

  • Version/tag: v0.5.3
  • Source identity: the commit peeled from the SSH-signed annotated tag; the exact commit is recorded in web-app-security-skill-0.5.3.release.json and the provenance attestation.
  • Runtime matrix: Node.js 22 and 24 on Ubuntu and macOS; Bash 3.2 remains covered on macOS.
  • Stable corpus: 20 built-in risk rules, two evidence-integrity rules and eight opt-in external adapter rules, unchanged from v0.5.2.

This file is part of the source commit it describes and therefore does not embed a fabricated self- referential source SHA. The signed tag, manifest and provenance establish the published source identity.

Distribution

The package named web-app-security-skill publishes the real zero-dependency CLI with both web-app-security-skill and webapp-security bin names. Its explicit file allowlist contains the runtime, skill instructions, rules, schemas, references, current limitations and benchmark evidence while excluding repository tests, launch/adoption notes and engineering plans. An isolated packed artifact runs version and a real source audit through offline npx.

Claude Code can add this repository as marketplace web-app-security and install plugin web-app-security-skill. The plugin uses the repository-root SKILL.md; no copied detector or second skill body exists. Both manifests validate with Claude Code 2.1.284, and an isolated Claude configuration completes marketplace add, plugin install and plugin listing.

Git diff source selection

audit <project> --since <ref> resolves the ref to an immutable commit, scans current tracked source with full file context and retains exact-location findings on added lines. It records but excludes untracked files. audit <project> --staged exports and scans the Git index, excluding unstaged working-tree content.

Path-level findings follow materially changed files. Missing-lockfile conclusions remain visible when a relevant manifest, workspace file or ancestor lockfile changes. Changed-file parse failures and global traversal incompleteness remain explicit unknown evidence. Pure content-identical renames do not replay findings.

Diff modes use the built-in adapter only and cannot use baseline/retest comparison. A clean diff report does not establish whole-repository safety.

Ground-truth pattern benchmark

npm run benchmark:ground-truth regenerates exact JSON and Markdown results from the stable corpus. The 20 risk contracts produce TP=20, FN=0, TN=20 and FP=0; the two evidence-integrity contracts produce TP=2, FN=0, TN=2 and FP=0, with no expected-state mismatch. Tests prove that deleting a positive observation produces an FN and that a safe-neighbour match produces an FP.

These are synthetic planted pattern-contract results. They do not measure production-vulnerability precision, recall, language coverage, reachability or exploitability. The five-project ordinary-code review remains separate evidence.

Known limitations and deferred expansion

KNOWN_LIMITATIONS.md publishes current parser, evidence-state, external-adapter, incremental and recurring benign-match boundaries. The v0.5.3 architecture decision defers MCP and additional stable rules. It defines client demand, permission, schema, local transport, distribution and failure tests for future MCP work, plus fixture, evidence-boundary, false-positive and fail-closed gates for every future stable rule.

Compatibility and security boundary

  • Finding/report v3, persisted-subject comparison and v2 migration semantics remain compatible.
  • Syntax and external scanner matches remain suspected until independent evidence confirms them.
  • Missing or failed source evidence remains unknown; unavailable evidence is never a pass.
  • Passive network defaults, authorization acknowledgements and review-only repair behavior are unchanged.
  • This release is not general SAST/DAST coverage, authenticated testing, an MCP service or proof that a project is secure.

Release verification

The release workflow runs npm run check, rebuilds all four release assets twice and compares every byte, verifies archive structure, checksums, manifest and SPDX SBOM, exercises isolated install and upgrade, then requests GitHub build provenance before publication.

Verify the signed tag:

git -c gpg.ssh.allowedSignersFile=.github/release-signers verify-tag v0.5.3

The published SHA256SUMS, manifest source commit, git rev-parse 'v0.5.3^{}', GitHub-recorded asset digests and provenance are verified before immutable asset digests are added to the installer. npm, verified installation and the mutable v1 alias are promoted only after their public consumers pass.