We got attacked via GitHub PRs
An open-source project experienced an attack via malicious pull requests on GitHub. The attacker attempted to exfiltrate sensitive information by manipulating the Dockerfile in the pull requests. In response, the project implemented security measures to restrict preview builds to approved contributors only.
- ▪The attacker opened seven pull requests with empty descriptions and a suspicious account name.
- ▪The CI pipeline allowed the attacker to exfiltrate some temporary secrets and keys due to the use of the pull_request_target event.
- ▪The project quickly rotated the exposed keys and implemented new security gates to prevent future attacks.
Opening excerpt (first ~120 words) tap to expand
← backWe got attacked via GitHub PRsMay 27, 2026 — security,open source,naoYesterday I saw a new PR on our open-source repo. The title was just t, and actually there were 7 of them. The descriptions were all empty, and the GitHub account didn't look legit either: it was created recently and named arc-switch. This is a small post to document what happened and what we changed. The PR nao is open-source. We get PRs from external contributors every day, and we decided a while ago to deploy a preview of each PR so we can test it during the review process. To do that, the CI pipeline builds the corresponding Docker image and deploys it to a preview VM. So yesterday the attacker (let's call him that way) opened 7 PRs, proposing changes in the Dockerfile to try to exfiltrate our secrets and envs.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at blef.fr.