Poisoned Pipeline / Techniques / T0122
Vulnerability in third-party CI/CD actions
CI/CD Posture Container Security Infrastructure as code Open Source Security
The use of 3rd party Github actions is very common.
Similar to using 3rd party libraries this can also introduce security risks - a malicious Github action has access to very sensitive information - i.e exfiltrating environment variables, including backdoors or malware in source code, infecting build artifacts.
Where this idea came from
tj-actions, Trivy Action tags, codfish floating tags; conference: Black Hat USA 2026 “GitHub Can Tell You’re Being Hacked. You’re Just Not Listening: Building EDR for GitHub from Its Own Event Stream” — defensive detection for the same surface. DEF CON 31: GitHub Actions Worm (Greenholts). DEF CON 33: tj-actions reconstruction (Hahami).
- https://www.truesec.com/hub/blog/secure-your-software-supply-chain-trusting-3rd-parties
- https://www.blackhat.com/us-26/briefings/schedule/index.html
- https://defcon.org/html/defcon-31/dc-31-speakers.html#Greenholts
- https://defcon.org/html/defcon-33/dc-33-speakers.html#content_60297
Mitigations
- M1120 Store credentials in vault
- M1220 Use only trusted third-party Github actions from reputable sources
- M1221 Review the Github action source code
- M1222 Limit the permissions granted to third-party Github actions
Detections
- D1260 Implement regular security audit and review
- D1261 Implement penetration testing
- D1262 Implement vulnerability assessment
- D1590 Implement continuous monitoring and logging of the CI/CD process
Observed in incidents (7)
- actions-cool GitHub Action tags still serve Mini Shai-Hulud after re-enablement
- codfish/semantic-release-action tag hijack (Miasma)
- Team PCP CI/CD secrets campaign
- tj-actions/changed-files GitHub Action
- Codecov Breach
- Ultralytics PyPI compromise
- TanStack Mini Shai-Hulud (CVE-2026-45321)