Unsecured Commands

• Query id: 60fd272d-15f4-4d8f-afe4-77d9c6cc0453
• Query name: Unsecured Commands
• Platform: CICD
• Severity: Medium
• Category: Insecure Configurations
• URL: Github

Description

There are deprecated set-env and add-path commands that can be explicitly enabled by a user via setting the ACTIONS_ALLOW_UNSECURE_COMMANDS environment variable as true. Depending on the use of the environment variable, this could enable an attacker to, at worst, modify the system path to run a different command than intended, resulting in arbitrary code execution.
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

name: Vulnerable workflow

on:
  pull_request_target

env:
  # 1. Enable unsecure commands
  ACTIONS_ALLOW_UNSECURE_COMMANDS: true
  ENVIRONMENT_NAME: prod

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      # 2. Print github context
      - run: |
          print("""${{ toJSON(github) }}""")
        shell: python
      - name: Create new PR deployment
        uses: actions/github-script@v5
        with:
          # 3. Create deployment
          script: |
            return await github.rest.repos.createDeployment({
                ...context.repo,
                ref: context.payload.pull_request.head.sha,
                auto_merge: false,
                required_contexts: [],
                environment: "${{ env.ENVIRONMENT_NAME }}",
                transient_environment: false,
                production_environment: false,
            });
          github-token: ${{ secrets.GITHUB_TOKEN }}

Positive test num. 2 - yaml file

name: Vulnerable workflow

on:
  pull_request_target


jobs:
  deploy:
    runs-on: ubuntu-latest
    env:
      ACTIONS_ALLOW_UNSECURE_COMMANDS: true
    steps:
      # 2. Print github context
      - run: |
          print("""${{ toJSON(github) }}""")
        shell: python
      - name: Create new PR deployment
        uses: actions/github-script@v5
        with:
          # 3. Create deployment
          script: |
            return await github.rest.repos.createDeployment({
                ...context.repo,
                ref: context.payload.pull_request.head.sha,
                auto_merge: false,
                required_contexts: [],
                environment: "${{ env.ENVIRONMENT_NAME }}",
                transient_environment: false,
                production_environment: false,
            });
          github-token: ${{ secrets.GITHUB_TOKEN }}

Positive test num. 3 - yaml file

name: Vulnerable workflow

on:
  pull_request_target

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      # 2. Print github context
      - run: |
          print("""${{ toJSON(github) }}""")
        shell: python
      - name: Create new PR deployment
        env:
          ACTIONS_ALLOW_UNSECURE_COMMANDS: true
        uses: actions/github-script@v5
        with:
          # 3. Create deployment
          script: |
            return await github.rest.repos.createDeployment({
                ...context.repo,
                ref: context.payload.pull_request.head.sha,
                auto_merge: false,
                required_contexts: [],
                environment: "${{ env.ENVIRONMENT_NAME }}",
                transient_environment: false,
                production_environment: false,
            });
          github-token: ${{ secrets.GITHUB_TOKEN }}

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

name: test-positive
on:
  pull_request:
    types: [opened, synchronize, edited, reopened]
    branches: 
      - master
jobs:
  test-positive:
    runs-on: ubuntu-latest
    steps:
    - name: PR comment
      uses: thollander/actions-comment-pull-request@b07c7f86be67002023e6cb13f57df3f21cdd3411
      with:
        comment_tag: title_check
        mode: recreate
        create_if_not_exists: true