Should organisations treat CI credentials as part of software supply chain security?

Why CI Credentials Belong in Supply Chain Security

CI credentials are not just a build-system concern. If a package, action, or dependency can execute during build or test time, those tokens can be harvested, abused, or chained into release manipulation. The right way to think about them is as release authority, because they can publish artifacts, access registries, read source, sign outputs, or reach other protected services.

That is why supply chain security needs to cover both the code you consume and the machine credentials that can act on that code. A compromised dependency becomes much more damaging when it runs in an environment that still holds broad CI privileges. SLSA is useful here because provenance and build integrity only hold when the pipeline itself is controlled tightly.

How the Attack Surface Expands During Builds

The practical risk is that CI often combines untrusted inputs with trusted authority. A startup script, dependency hook, or malicious package install can read environment variables, reach mounted secrets, or call internal APIs if those permissions are present. Once a token is exposed, an attacker no longer needs to stay inside the build job, they can move to repository changes, artifact tampering, or downstream service abuse.

This is why short-lived and narrowly scoped credentials matter. They reduce what a hostile dependency can do even if execution happens in a trusted pipeline. The same principle is reflected in OWASP Non-Human Identity Top 10, which treats overprivilege, long-lived secrets, and insecure authentication as separate failure modes, not as implementation details.

Hosted build and test environments deserve extra caution because they often expose tokens through logs, metadata, cache layers, or injected environment variables. The harder the pipeline is to observe and the wider the token scope, the easier it is for an attacker to turn one malicious install into a broader release compromise.

What Good Control Looks Like in Practice

Good practice is to treat every CI credential as an asset with a clear purpose, lifetime, and blast radius. That means deciding whether the job truly needs write access, registry publish rights, signing authority, or only read access to fetch dependencies. Where possible, replace reusable long-lived secrets with federated identity, ephemeral credentials, or tightly scoped publishing tokens.

For release pipelines, NIST SSDF (SP 800-218) supports the broader discipline of building and verifying software securely, while CI/CD Pipeline Identity Security Guide shows how to apply keyless federation, trust policy, and token minimisation in the pipeline itself. If the pipeline can sign or publish, those privileges should be separated from ordinary test execution.

Operationally, the best indicator is not whether credentials exist, but whether they can be used outside the intended stage, repository, environment, or time window. If a build token can still authenticate after the job ends, or can reach production-adjacent systems, it is carrying too much authority for a supply chain context.

Risk and Threat Considerations

CI credentials create a supply chain risk because the attacker does not need to break the pipeline first, only to get code or tooling to run inside it. Once that happens, a token with publish, read, or signing authority can turn a single malicious dependency into artifact poisoning, secret theft, or unauthorized release activity.

Failure mechanism: Untrusted build-time execution reaches CI environment variables, cached material, mounted secrets, or cloud metadata, then reuses exposed credentials before they expire or are revoked.

Impact: Attackers can modify builds, publish tampered artifacts, access registries or source systems, and widen compromise beyond the original dependency to downstream consumers and release channels.

Practitioner Guidance

What to prioritise: Start with any CI credential that can publish, sign, deploy, or read sensitive source and release material. Those are the credentials that convert a build-time compromise into a supply chain compromise.

What to verify: Confirm that build jobs receive only the minimum scope they need, that tokens expire quickly, and that untrusted jobs cannot inherit the same authority as trusted release jobs.

Common mistake: Teams often harden dependency scanning while leaving pipeline tokens broad and persistent. That creates a false sense of control because the malicious package can still use the pipeline’s own trust.

Practitioner takeaway: Treat CI credentials as part of the supply chain trust boundary, not as a separate infrastructure detail, and design them so compromise of one build cannot become authority over release.

Related resources from NHI Mgmt Group

• Should organisations treat licence compliance as part of software supply-chain risk?
• Should organisations treat extension review as part of software supply-chain governance?
• How should security teams govern software supply chain risk when CI/CD identities can publish code?
• Why do CI/CD tokens and maintainer credentials matter so much in supply chain security?