GitHub Actions Abuse Exposed CI/CD Secrets and Azure OIDC Trust Weaknesses

A GitHub Actions supply-chain attack compromised widely used actions including tj-actions/changed-files and components in the reviewdog ecosystem after attackers abused insecure workflow patterns to steal maintainer personal access tokens and move trusted tags to malicious code. Investigators traced the intrusion to a malicious pull request against the SpotBugs ecosystem using the dangerous pull_request_target trigger, which exposed a maintainer token that was later used to implant another workflow, steal additional tokens, and overwrite action tags. The malicious action chain leaked CI/CD secrets and environment variables by dumping runner memory into workflow logs, affecting downstream repositories at scale and including a targeted attempt involving Coinbase, which said the incident did not damage its assets.

Separate research showed that GitHub Actions integrations with Azure via OpenID Connect can also be undermined when federated identity credentials trust unsafe subject identifiers such as unprotected branches, tags, environments, or especially pull_request, allowing contributors to obtain Azure access tokens under weak configurations. The analysis found that even reusable workflows constrained with job_workflow_ref can still expose cloud access if the workflow permits caller-controlled code execution through mechanisms such as script injection or Terraform plan behavior. Together, the findings show that GitHub Actions trust boundaries can fail both in software supply chains and cloud federation unless organizations pin actions to commit SHAs, protect refs, minimize token permissions, validate reusable workflows, and enforce least-privilege access to secrets and cloud roles.