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Security Advisories: GSA_kwCzR0hTQS1odzZyLWc4Z2otMjk4N84AA1lL

Actions expression injection in `filter-test-configs` (`GHSL-2023-181`)

The pytorch/pytorch filter-test-configs workflow is vulnerable to an expression injection in Actions, allowing an attacker to potentially leak secrets and alter the repository using the workflow.

Details

The filter-test-configs workflow is using the raw github.event.workflow_run.head_branch value inside the filter step:

- name: Select all requested test configurations
  shell: bash
  env:
    GITHUB_TOKEN: ${{ inputs.github-token }}
    JOB_NAME: ${{ steps.get-job-name.outputs.job-name }}
  id: filter
  run: |
    ...
    python3 "${GITHUB_ACTION_PATH}/../../scripts/filter_test_configs.py" \
      ...
      --branch "${{ github.event.workflow_run.head_branch }}"

In the event of a repository using filter-test-configs in a pull_request_target-triggered workflow, an attacker could use a malicious branch name to gain command execution in the step and potentially leak secrets.

name: Example

on: pull_request_target

jobs:
  example:
    runs-on: ubuntu-latest
    steps:
      - name: Filter
        uses: pytorch/pytorch/.github/actions/filter-test-configs@v2

Impact

This issue may lead to stealing workflow secrets.

Remediation

  1. Use an intermediate environment variable for potentially attacker-controlled values such as github.event.workflow_run.head_branch:
- name: Select all requested test configurations
  shell: bash
  env:
    GITHUB_TOKEN: ${{ inputs.github-token }}
    JOB_NAME: ${{ steps.get-job-name.outputs.job-name }}
    HEAD_BRANCH: ${{ github.event.workflow_run.head_branch }}
  id: filter
  run: |
    ...
    python3 "${GITHUB_ACTION_PATH}/../../scripts/filter_test_configs.py" \
      ...
      --branch "$HEAD_BRANCH"

Resources

Permalink: https://github.com/advisories/GHSA-hw6r-g8gj-2987
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS1odzZyLWc4Z2otMjk4N84AA1lL
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 8 months ago
Updated: 8 months ago


Identifiers: GHSA-hw6r-g8gj-2987
References: Repository: https://github.com/pytorch/pytorch
Blast Radius: 1.0

Affected Packages

actions:https://github.com/pytorch/pytorch/.github/actions/filter-test-configs
Affected Version Ranges: < 2.0.1
No known fixed version