Open JarLob opened 3 years ago
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Disabled the workflow for now.
We have been unsuccessfully trying to contact the repository owners since 2020-11-30. The issue affects
master
,Janglee123-patch-2
,Janglee123-patch-1
andrevert-83-master
branches.Summary
The auto_merge.yml GitHub workflow is vulnerable to unauthorized modification of the base repository or secrets exfiltration from a Pull Request.
Tested Version
The latest changeset a43fb3c 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.
Impact
The vulnerability allows for unauthorized modification of the base repository and secrets exfiltration.
Remediation
Use
pull_request
trigger that doesn't have read/write repository token and no access to secrets. If at some point a write access is needed split the workflow in two and useworkflow_run
.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 toGHSL-2020-313
in any communication regarding this issue.Disclosure Policy
This report is subject to our coordinated disclosure policy.