ExcessiveSecretsExposure.md

Overview

When the workflow runner cannot determine what secrets are needed to run the workflow, it will pass all the available secrets to the runner including organization and repository secrets. This violates the least privileged principle and increases the impact of a potential vulnerability affecting the workflow.

Recommendation

Only pass those secrets that are needed by the workflow. Avoid using expressions such as toJSON(secrets) or dynamically accessed secrets such as secrets[format('GH_PAT_%s', matrix.env)] since the workflow will need to receive all secrets to decide at runtime which one needs to be used.

Example

Incorrect Usage

env:
  ALL_SECRETS: ${{ toJSON(secrets) }}

strategy:
  matrix:
    env: [PROD, DEV]
env:
  GH_TOKEN: ${{ secrets[format('GH_PAT_%s', matrix.env)] }}

Correct Usage

env:
  NEEDED_SECRET: ${{ secrets.GH_PAT }}

strategy:
  matrix:
    env: [PROD, DEV]
---
if: matrix.env == "PROD"
env:
  GH_TOKEN: ${{ secrets.GH_PAT_PROD }}
---
if: matrix.env == "DEV"
env:
  GH_TOKEN: ${{ secrets.GH_PAT_DEV }}

References

• GitHub Docs: Using secrets in GitHub Actions.
• poutine: Job uses all secrets.