Pin third-party GitHub Actions to commit SHAs - #615
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Third-party actions were referenced by movable major tags (e.g. actions/checkout@v6). A tag can be repointed by the upstream owner or an attacker who compromises that action's repo, silently running new code in our CI - the class of supply-chain attack seen with tj-actions in 2025. Pin the externally-owned actions to the immutable commit SHA the tag resolves to, with the version kept in a trailing comment. Dependabot (github-actions ecosystem) updates both the SHA and the comment together, so they do not drift. Pinned: actions/checkout, actions/setup-node, actions/github-script, actions/stale, github/codeql-action (init/autobuild/analyze). Deliberately NOT pinned: azure/login and azure/powershell stay on @V3. These are our own actions used as test/provisioning tooling - the canary and integration suites exist to validate the current v3, so pinning them to a SHA would freeze what the tests exercise and cause them to drift from the released major. The supply-chain threat model (us attacking our own action's CI) does not apply. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Yeming Liu (isra-fel)
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Summary
Pins externally-owned GitHub Actions to immutable commit SHAs to reduce supply-chain risk.
Changes
Third-party actions were referenced by movable major tags (e.g.
actions/checkout@v6). A tag can be repointed by the upstream owner, or by an attacker who compromises that action's repository, silently running new code in our CI with our permissions. This is the class of attack seen withtj-actionsin 2025.Each externally-owned action is now pinned to the commit SHA its tag currently resolves to, with the human-readable version kept in a trailing comment:
actions/checkout→ v6.1.0actions/setup-node→ v6.5.0actions/github-script→ v7.1.0actions/stale→ v8.0.0github/codeql-action(init/autobuild/analyze) → v3.37.7Maintenance
Dependabot is already configured for the
github-actionsecosystem. It understands SHA pins and raises update PRs that bump both the SHA and the trailing version comment together, so the pins stay current without manual tracking and do not drift from the comment.Deliberately not pinned
azure/loginandazure/powershellstay on@v3. These are our own actions used as test and provisioning tooling; the canary and integration suites exist to validate the currentv3, so pinning them to a SHA would freeze what the tests exercise and cause drift from the released major. The supply-chain threat model does not apply to our own action's CI.