Coordinated Disclosure Timeline
- 2020-11-26-2020-12-12: Report sent to various maintainers.
- 2020-12-11: No reply. Created public issue asking for security contact.
- 2020-12-12: Report sent to the provided contact.
- 2020-12-15: Report acknowledged.
- 2020-12-16: Issue resolved.
Summary
The ‘node-pr-jobs-secure.yml’ GitHub workflow is vulnerable to arbitrary code execution.
Product
strimzi/strimzi-ui GitHub repository
Tested Version
The latest changeset 5e277d4 to the date.
Details
Issue: Untrusted code is explicitly checked out and run on a Pull Request from a fork
pull_request_target was introduced to allow triggered workflows to comment on PRs, label them, assign people, etc.. In order to make it possible the triggered action runner has read/write token for the base repository and the access to secrets. In order to prevent untrusted code from execution it runs in a context of the base repository.
By explicitly checking out and running build script from a fork the untrusted code is running in an environment that is able to push to the base repository and to access secrets.
# Running target makes it secure as this is the only way to get hold of github secrets
on: [pull_request_target]
...
- name: Checkout PR Branch
uses: actions/checkout@v2
with:
repository: ${{github.event.pull_request.head.repo.full_name}}
ref: ${{github.event.pull_request.head.ref}}
fetch-depth: 0
- name: Use Node.js 14.x
uses: actions/setup-node@v1
with:
node-version: 14.x
- name: Install Dependencies and setup for CI
run: |
npm ci
npm run addDevCerts
- name: Build
run: npm run build
Impact
The vulnerability allows for unauthorized modification of the base repository and secrets exfiltration.
Credit
This issue was discovered and reported by GHSL team member @JarLob (Jaroslav Lobačevski).
Contact
You can contact the GHSL team at securitylab@github.com, please include a reference to GHSL-2020-245 in any communication regarding this issue.