어떤 스킬인가요?
외부 기여를 받는 저장소나 배포 자동화를 만드는 프로젝트에서 활용합니다. 어떤 이벤트로 실행되는지, 신뢰하지 않는 코드가 권한이 있는 작업에 섞이는지를 중심으로 점검합니다.
워크플로 파일과 사용하는 액션, 비밀값 접근 범위를 함께 제공하세요. 위험한 입력이 셸 명령이나 배포 단계에 도달하는 경로를 확인하고 권한을 줄이는 방향을 요청할 수 있습니다. 실제 배포 설정을 변경하기 전에 테스트 저장소에서 영향을 살펴보세요.
gha-security-review · 스킬 지원 에이전트
GitHub Actions에서 외부 PR 입력, 토큰 권한과 실행 흐름의 보안 문제를 검토합니다.
외부 기여를 받는 저장소나 배포 자동화를 만드는 프로젝트에서 활용합니다. 어떤 이벤트로 실행되는지, 신뢰하지 않는 코드가 권한이 있는 작업에 섞이는지를 중심으로 점검합니다.
워크플로 파일과 사용하는 액션, 비밀값 접근 범위를 함께 제공하세요. 위험한 입력이 셸 명령이나 배포 단계에 도달하는 경로를 확인하고 권한을 줄이는 방향을 요청할 수 있습니다. 실제 배포 설정을 변경하기 전에 테스트 저장소에서 영향을 살펴보세요.
gha-security-review로 아래 워크플로를 검토해줘. 외부 PR 입력과 GITHUB_TOKEN 권한을 추적하고 위험 근거와 최소 권한 설정안을 제안해줘.
받을 수 있는 결과워크플로 취약점과 권한 개선안
2026-10-05 격리된 YAML과 스크립트를 읽어 검토했습니다. GitHub에 업로드하거나 실제 워크플로를 실행하지 않았습니다.
예제 워크플로는 pull_request_target에서 시작하고 contents: write 권한을 사용했습니다. 이후 PR의 head commit을 체크아웃하고 그 안의 user-script.js를 실행했습니다. 이벤트 이름, 권한, 체크아웃 대상과 실행 파일을 이어서 보는 것이 중요합니다.
event: pull_request_target
permissions: contents: write
checkout ref: github.event.pull_request.head.sha
run: node user-script.js외부 기여자가 바꿀 수 있는 파일을 권한이 있는 작업에서 실행하게 됩니다. 각각의 설정을 따로 읽으면 놓치기 쉽습니다. 검토 결과에서는 신뢰할 수 없는 PR 테스트와 신뢰한 코드의 릴리스 작업을 분리하는 방향을 제안했습니다.
어떤 이벤트에서 실행되는지, 실제 필요한 권한은 무엇인지, 외부 코드를 실행하는 단계가 있는지부터 확인하세요. 환경별 토큰과 저장소 설정에 따라 영향이 달라집니다. 이 예제의 검토를 내 저장소의 안전성 보장으로 해석해서는 안 됩니다.
스킬 지원 에이전트와 워크플로 파일이 필요합니다. CI 실행·권한 변경·배포는 별도입니다.
현재 사용 중인 스킬 지원 에이전트에 아래 요청을 붙여넣으세요. SKILL.md만 복사하면 보조 파일이 빠질 수 있어요.
https://github.com/getsentry/skills 에서 skills/gha-security-review 스킬을 현재 에이전트의 스킬 폴더에 설치해줘. SKILL.md와 이 스킬이 참조하는 scripts·references·assets와 공통 파일을 함께 유지하고, 필요한 실행 환경과 추가 연결을 확인한 뒤 알려줘. 설치가 끝나면 gha-security-review 스킬을 인식하는지 확인해줘.
“gha-security-review 스킬을 사용해줘. 입력 자료: .github/workflows·이벤트·권한 설정”처럼 요청하세요. 위의 예시를 내 자료에 맞게 바꿔도 좋아요.
예상 결과는 ‘워크플로 취약점과 권한 개선안’입니다. 필요한 내용이 포함됐는지 확인하세요. 입력 자료의 사실·숫자와 결과를 대조하고, 부족한 부분을 이어서 요청하세요.
제작자 원본 2026-10-04 확인 · 설치 안내 2026-10-04 확인 · 격리 폴더 설치·샘플 검토 2026-10-05 확인 · 에이전트 자동 호출 미검증
모델 사용 요금과 연결 앱 요금은 이용 중인 서비스의 정책을 따릅니다.
설치 안내 출처--- name: gha-security-review description: 'GitHub Actions security review for workflow exploitation vulnerabilities. Use when asked to "review GitHub Actions", "audit workflows", "check CI security", "GHA security", "workflow security review", or review .github/workflows/ for pwn requests, expression injection, credential theft, and supply chain attacks. Exploitation-focused with concrete PoC scenarios.' allowed-tools: Read Grep Glob Bash Task --- <!-- Attack patterns and real-world examples sourced from the HackerBot Claw campaign analysis by StepSecurity (2025): https://www.stepsecurity.io/blog/hackerbot-claw-github-actions-exploitation --> # GitHub Actions Security Review Find exploitable vulnerabilities in GitHub Actions workflows. Every finding MUST include a concrete exploitation scenario — if you can't build the attack, don't report it. This skill encodes attack patterns from real GitHub Actions exploits — not generic CI/CD theory. ## Scope Review the workflows provided (file, diff, or repo). Research the codebase as needed to trace complete attack paths before reporting. ### Files to Review - `.github/workflows/*.yml` — all workflow definitions - `action.yml` / `action.yaml` — composite actions in the repo--- name: gha-security-review description: 'GitHub Actions security review for workflow exploitation vulnerabilities. Use when asked to "review GitHub Actions", "audit workflows", "check CI security", "GHA security", "workflow security review", or review .github/workflows/ for pwn requests, expression injection, credential theft, and supply chain attacks. Exploitation-focused with concrete PoC scenarios.' allowed-tools: Read Grep Glob Bash Task --- <!-- Attack patterns and real-world examples sourced from the HackerBot Claw campaign analysis by StepSecurity (2025): https://www.stepsecurity.io/blog/hackerbot-claw-github-actions-exploitation --> # GitHub Actions Security Review Find exploitable vulnerabilities in GitHub Actions workflows. Every finding MUST include a concrete exploitation scenario — if you can't build the attack, don't report it. This skill encodes attack patterns from real GitHub Actions exploits — not generic CI/CD theory. ## Scope Review the workflows provided (file, diff, or repo). Research the codebase as needed to trace complete attack paths before reporting. ### Files to Review - `.github/workflows/*.yml` — all workflow definitions - `action.yml` / `action.yaml` — composite actions in the repo - `.github/actions/*/action.yml` — local reusable actions - Config files loaded by workflows: `CLAUDE.md`, `AGENTS.md`, `Makefile`, shell scripts under `.github/` ### Out of Scope - Workflows in other repositories (only note the dependency) - GitHub App installation permissions (note if relevant) ## Threat Model Only report vulnerabilities exploitable by an **external attacker** — someone **without** write access to the repository. The attacker can open PRs from forks, create issues, and post comments. They cannot push to branches, trigger `workflow_dispatch`, or trigger manual workflows. **Do not flag** vulnerabilities that require write access to exploit: - `workflow_dispatch` input injection — requires write access to trigger - Expression injection in `push`-only workflows on protected branches - `workflow_call` input injection where all callers are internal - Secrets in `workflow_dispatch`/`schedule`-only workflows ## Confidence Report only **HIGH** and **MEDIUM** confidence findings. Do not report theoretical issues. | Confidence | Criteria | Action | |---|---|---| | **HIGH** | Traced the full attack path, confirmed exploitable | Report with exploitation scenario and fix | | **MEDIUM** | Attack path partially confirmed, uncertain link | Report as needs verification | | **LOW** | Theoretical or mitigated elsewhere | Do not report | For each HIGH finding, provide all five elements: 1. **Entry point** — How does the attacker get in? (fork PR, issue comment, branch name, etc.) 2. **Payload** — What does the attacker send? (actual code/YAML/input) 3. **Execution mechanism** — How does the payload run? (expression expansion, checkout + script, etc.) 4. **Impact** — What does the attacker gain? (token theft, code execution, repo write access) 5. **PoC sketch** — Concrete steps an attacker would follow If you cannot construct all five, report as MEDIUM (needs verification). --- ## Step 1: Classify Triggers and Load References For each workflow, identify triggers and load the appropriate reference: | Trigger / Pattern | Load Reference | |---|---| | `pull_request_target` | `references/pwn-request.md` | | `issue_comment` with command parsing | `references/comment-triggered-commands.md` | | `${{ }}` in `run:` blocks | `references/expression-injection.md` | | PATs / deploy keys / elevated credentials | `references/credential-escalation.md` | | Checkout PR code + config file loading | `references/ai-prompt-injection-via-ci.md` | | Third-party actions (especially unpinned) | `references/supply-chain.md` | | `permissions:` block or secrets usage | `references/permissions-and-secrets.md` | | Self-hosted runners, cache/artifact usage | `references/runner-infrastructure.md` | | Any confirmed finding | `references/real-world-attacks.md` | Load references selectively — only what's relevant to the triggers found. ## Step 2: Check for Vulnerability Classes ### Check 1: Pwn Request Does the workflow use `pull_request_target` AND check out fork code? - Look for `actions/checkout` with `ref:` pointing to PR head - Look for local actions (`./.github/actions/`) that would come from the fork - Check if any `run:` step executes code from the checked-out PR ### Check 2: Expression Injection Are `${{ }}` expressions used inside `run:` blocks in externally-triggerable workflows? - Map every `${{ }}` expression in every `run:` step - Confirm the value is attacker-controlled (PR title, branch name, comment body — not numeric IDs, SHAs, or repository names) - Confirm the expression is in a `run:` block, not `if:`, `with:`, or job-level `env:` ### Check 3: Unauthorized Command Execution Does an `issue_comment`-triggered workflow execute commands without authorization? - Is there an `author_association` check? - Can any GitHub user trigger the command? - Does the command handler also use injectable expressions? ### Check 4: Credential Escalation Are elevated credentials (PATs, deploy keys) accessible to untrusted code? - What's the blast radius of each secret? - Could a compromised workflow steal long-lived tokens? ### Check 5: Config File Poisoning Does the workflow load configuration from PR-supplied files? - AI agent instructions: `CLAUDE.md`, `AGENTS.md`, `.cursorrules` - Build configuration: `Makefile`, shell scripts ### Check 6: Supply Chain Are **third-party** actions securely pinned to full SHAs? - Pin third-party / external actions and reusable workflows only - Do **not** flag first-party `actions/*` or `github/*` on version tags - Do **not** flag same-repo / vendored (`./.github/actions/...`) as supply-chain pinning issues - Only report when the job has secrets, OIDC, write token, release, deploy, package, or signing power — unprivileged read-only CI is not a finding ### Check 7: Permissions and Secrets Are workflow permissions minimal? Are secrets properly scoped? ### Check 8: Runner Infrastructure Are self-hosted runners, caches, or artifacts used securely? ## Safe Patterns (Do Not Flag) Before reporting, check if the pattern is actually safe: | Pattern | Why Safe | |---|---| | `pull_request_target` WITHOUT checkout of fork code | Never executes attacker code | | `${{ github.event.pull_request.number }}` in `run:` | Numeric only — not injectable | | `${{ github.repository }}` / `github.repository_owner` | Repo owner controls this | | `${{ secrets.* }}` | Not an expression injection vector | | `${{ }}` in `if:` conditions | Evaluated by Actions runtime, not shell | | `${{ }}` in `with:` inputs | Passed as string parameters, not shell-evaluated | | Third-party actions pinned to full SHA | Immutable reference | | First-party `actions/*` / `github/*` on version tags | Outside third-party pinning policy — do not flag | | Same-repo / vendored local actions | Not third-party supply chain (review pwn-request separately) | | `pull_request` trigger (not `_target`) | Runs in fork context with read-only token | | Any expression in `workflow_dispatch`/`schedule`/`push` to protected branches | Requires write access — outside threat model | **Key distinction:** `${{ }}` is dangerous in `run:` blocks (shell expansion) but safe in `if:`, `with:`, and `env:` at the job/step level (Actions runtime evaluation). ## Step 3: Validate Before Reporting Before including any finding, read the actual workflow YAML and trace the complete attack path: 1. **Read the full workflow** — don't rely on grep output alone 2. **Trace the trigger** — confirm the event and check `if:` conditions that gate execution 3. **Trace the expression/checkout** — confirm it's in a `run:` block or actually references fork code 4. **Confirm attacker control** — verify the value maps to something an external attacker sets 5. **Check existing mitigations** — env var wrapping, author_association checks, restricted permissions, SHA pinning If any link is broken, mark MEDIUM (needs verification) or drop the finding. **If no checks produced a finding, report zero findings. Do not invent issues.** ## Step 4: Report Findings ````markdown ## GitHub Actions Security Review ### Findings #### [GHA-001] [Title] (Severity: Critical/High/Medium) - **Workflow**: `.github/workflows/release.yml:15` - **Trigger**: `pull_request_target` - **Confidence**: HIGH — confirmed through attack path tracing - **Exploitation Scenario**: 1. [Step-by-step attack] - **Impact**: [What attacker gains] - **Fix**: [Code that fixes the issue] ### Needs Verification [MEDIUM confidence items with explanation of what to verify] ### Reviewed and Cleared [Workflows reviewed and confirmed safe] ```` If no findings: "No exploitable vulnerabilities identified. All workflows reviewed and cleared."
Original skill: getsentry/skills/skills/gha-security-review/SKILL.md
Source: https://github.com/getsentry/skills/blob/d18b7aa8ba878354e5c348310230e652f7690f9c/skills/gha-security-review/SKILL.md
License: Apache-2.0
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SKILL.md 본문입니다. 원문에서 참조하는 스크립트·보조 파일은 원본 패키지에 포함되어 있습니다.