The cascading provide chain assault that initially focused Coinbase earlier than turning into extra widespread to single out customers of the “tj-actions/changed-files” GitHub Motion has been traced additional again to the theft of a private entry token (PAT) associated to SpotBugs.
“The attackers obtained preliminary entry by benefiting from the GitHub Actions workflow of SpotBugs, a well-liked open-source software for static evaluation of bugs in code,” Palo Alto Networks Unit 42 stated in an replace this week. “This enabled the attackers to maneuver laterally between SpotBugs repositories, till acquiring entry to reviewdog.”
There’s proof to counsel that the malicious exercise started way back to November, 2024, though the assault in opposition to Coinbase didn’t happen till March 2025.
Unit 42 stated its investigation started with the data that reviewdog’s GitHub Motion was compromised as a result of a leaked PAT related to the mission’s maintainer, which subsequently enabled the risk actors to push a rogue model of “reviewdog/action-setup” that, in flip, was picked up by “tj-actions/changed-files” as a result of it being listed as a dependency through the “tj-actions/eslint-changed-files” motion.
It has since been uncovered that the maintainer was additionally an energetic participant in one other open-source mission referred to as SpotBugs.
The attackers are stated to have pushed a malicious GitHub Actions workflow file to the “spotbugs/spotbugs” repository beneath the disposable username “jurkaofavak,” inflicting the maintainer’s PAT to be leaked when the workflow was executed.
It is believed that the identical PAT facilitated entry to each “spotbugs/spotbugs” and “reviewdog/action-setup,” that means the leaked PAT may very well be abused to poison “reviewdog/action-setup.”
“The attacker in some way had an account with write permission in spotbugs/spotbugs, which they had been in a position to make use of to push a department to the repository and entry the CI secrets and techniques,” Unit 42 stated.
As for a way the write permissions had been obtained, it has come to mild that the person behind the malicious decide to SpotBugs, “jurkaofavak,” was invited to the repository as a member by one of many mission maintainers themselves on March 11, 2025.
In different phrases, the attackers managed to acquire the PAT of the SpotBugs repository to ask “jurkaofavak” to grow to be a member. This, the cybersecurity firm stated, was carried out by making a fork of the “spotbugs/sonar-findbugs” repository and making a pull request beneath the username “randolzfow.”
“On 2024-11-28T09:45:13 UTC, [the SpotBugs maintainer] modified one of many ‘spotbugs/sonar-findbugs workflows to make use of their very own PAT, as they had been having technical difficulties in part of their CI/CD course of,” Unit 42 defined.
“On 2024-12-06 02:39:00 UTC, the attacker submitted a malicious pull request to spotbugs/sonar-findbugs, which exploited a GitHub Actions workflow that used the pull_request_target set off.”
The “pull_request_target” set off is a GitHub Actions workflow set off that permits workflows working from forks to entry secrets and techniques – on this case, the PAT – resulting in what’s referred to as a poisoned pipeline execution assault (PPE).
The SpotBugs maintainer has since confirmed that the PAT that was used as a secret within the workflow was the identical entry token that was later used to ask “jurkaofavak” to the “spotbugs/spotbugs” repository. The maintainer has additionally rotated all of their tokens and PATs to revoke and stop additional entry by the attackers.
One main unknown in all that is the three-month hole between when the attackers leaked the SpotBugs maintainer’s PAT and after they abused it. It is suspected that the attackers had been retaining a watch out on the initiatives that had been depending on “tj-actions/changed-files” and waited to strike a high-value goal like Coinbase.
“Having invested months of effort and after reaching a lot, why did the attackers print the secrets and techniques to logs, and in doing so, additionally reveal their assault?,” Unit 42 researchers contemplated.
