GitHub Workflow Contains Checkout Action

Severity: informational
Log types: GitHub.Webhook
Tags: CI/CD, Workflow, Supply Chain
Reference: https://securitylab.github.com/research/github-actions-preventing-pwn-requests/
Source: github.com/panther-labs/panther-analysis

Detects when a GitHub Actions workflow job contains a checkout step. The checkout action (actions/checkout) pulls repository code into the workflow runner. In certain contexts, especially with pull_request_target triggers or workflows with elevated permissions, checking out untrusted code can pose security risks. This detection helps identify workflows that interact with repository code for security review.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1195.002` Supply Chain Compromise: Compromise Software Supply Chain
Execution	`T1072` Software Deployment Tools

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

GitHub pull_request_target Workflow Usage (Panther)
GitHub Workflow Downloading Artifacts (Panther)
GitHub Workflow Using Self-Hosted Runner (Panther)

Rule body yaml

AnalysisType: rule
Filename: github_workflow_contains_checkout.py
RuleID: "GitHub.Webhook.WorkflowContainsCheckout"
DisplayName: "GitHub Workflow Contains Checkout Action"
Enabled: true
LogTypes:
  - GitHub.Webhook
Reports:
  MITRE ATT&CK:
    - TA0001:T1195.002  # Supply Chain Compromise: Compromise Software Supply Chain
    - TA0002:T1072  # Execution: Software Deployment Tools
Tags:
  - CI/CD
  - Workflow
  - Supply Chain
Severity: Info
CreateAlert: false
Description: >
  Detects when a GitHub Actions workflow job contains a checkout step. The checkout action
  (actions/checkout) pulls repository code into the workflow runner. In certain contexts,
  especially with pull_request_target triggers or workflows with elevated permissions,
  checking out untrusted code can pose security risks. This detection helps identify
  workflows that interact with repository code for security review.
Reference: https://securitylab.github.com/research/github-actions-preventing-pwn-requests/
Tests:
  - Name: "Workflow job with checkout step completed"
    ExpectedResult: true
    Log:
      action: "completed"
      workflow_job:
        id: 52841914522
        name: "Validate PR Title"
        status: "completed"
        conclusion: "success"
        html_url: "https://github.com/example-org/example-repo/actions/runs/12345678/job/52841914522"
        head_branch: "feature-branch"
        head_sha: "abc123def456789"
        run_id: 12345678
        runner_name: "GitHub Actions"
        started_at: "2025-10-15T18:41:58Z"
        completed_at: "2025-10-15T18:47:18Z"
        steps:
          - completed_at: "2025-10-15T18:42:00Z"
            conclusion: "success"
            name: "Set up job"
            number: 1
            started_at: "2025-10-15T18:41:59Z"
            status: "completed"
          - completed_at: "2025-10-15T18:42:02Z"
            conclusion: "success"
            name: "Checkout code"
            number: 2
            started_at: "2025-10-15T18:42:00Z"
            status: "completed"
          - completed_at: "2025-10-15T18:42:05Z"
            conclusion: "success"
            name: "Run tests"
            number: 3
            started_at: "2025-10-15T18:42:02Z"
            status: "completed"
      repository:
        id: 123456789
        full_name: "example-org/example-repo"
        private: true

  - Name: "Workflow job with case-insensitive checkout variation"
    ExpectedResult: true
    Log:
      action: "completed"
      workflow_job:
        id: 52841914523
        name: "Build"
        status: "completed"
        conclusion: "success"
        steps:
          - name: "Setup environment"
            status: "completed"
            conclusion: "success"
          - name: "CHECKOUT Repository"
            status: "completed"
            conclusion: "success"
          - name: "Build project"
            status: "completed"
            conclusion: "success"
      repository:
        id: 123456789
        full_name: "example-org/example-repo"

  - Name: "Workflow job with 'Post Checkout' step"
    ExpectedResult: true
    Log:
      action: "completed"
      workflow_job:
        id: 52841914524
        name: "Deploy"
        status: "completed"
        conclusion: "success"
        steps:
          - name: "Initialize"
            status: "completed"
            conclusion: "success"
          - name: "Post Checkout code"
            status: "completed"
            conclusion: "success"
          - name: "Deploy application"
            status: "completed"
            conclusion: "success"
      repository:
        id: 123456789
        full_name: "example-org/example-repo"

  - Name: "Workflow job without checkout step"
    ExpectedResult: false
    Log:
      action: "completed"
      workflow_job:
        id: 52841914525
        name: "Lint"
        status: "completed"
        conclusion: "success"
        steps:
          - name: "Set up job"
            status: "completed"
            conclusion: "success"
          - name: "Run linter"
            status: "completed"
            conclusion: "success"
          - name: "Complete job"
            status: "completed"
            conclusion: "success"
      repository:
        id: 123456789
        full_name: "example-org/example-repo"

  - Name: "Workflow job requested (not completed)"
    ExpectedResult: false
    Log:
      action: "requested"
      workflow_job:
        id: 52841914526
        name: "Test"
        status: "queued"
        steps:
          - name: "Checkout code"
            status: "pending"
      repository:
        id: 123456789
        full_name: "example-org/example-repo"

  - Name: "Workflow job with empty steps array"
    ExpectedResult: false
    Log:
      action: "completed"
      workflow_job:
        id: 52841914527
        name: "Empty Job"
        status: "completed"
        conclusion: "skipped"
        steps: []
      repository:
        id: 123456789
        full_name: "example-org/example-repo"

  - Name: "Workflow job with null steps"
    ExpectedResult: false
    Log:
      action: "completed"
      workflow_job:
        id: 52841914528
        name: "Null Steps Job"
        status: "completed"
        conclusion: "success"
      repository:
        id: 123456789
        full_name: "example-org/example-repo"

  - Name: "Workflow job in progress with checkout"
    ExpectedResult: false
    Log:
      action: "in_progress"
      workflow_job:
        id: 52841914529
        name: "Build"
        status: "in_progress"
        steps:
          - name: "Checkout code"
            status: "completed"
            conclusion: "success"
          - name: "Build"
            status: "in_progress"
      repository:
        id: 123456789
        full_name: "example-org/example-repo"

Detection logic

Condition

action eq "completed"
workflow_job.steps array_any

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`action`	eq	`completed`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)