Suspicious Google Cloud Function Create or Update Triggering Build

PremiumReviewedSigma · Low · v1
Product
gcp
Service
gcp.audit
Author
HuntRule
Published
2026-09-10
Updated
2026-09-10

ATT&CK techniques

Initial Access → Defense Evasion
  1. Recon

  2. Resource Dev

  3. Cred Access

  4. Discovery

  5. Lateral Movement

  6. Collection

  7. C2

  8. Exfiltration

  9. Impact

What it detects

This rule detects creation or modification of a Google Cloud Function which automatically triggers a build using the default Cloud Build service account. Talos observed this serverless attack vector where an actor deploys a malicious function to execute attacker code during the build and inherit the over-privileged build service account, so unexpected function writes warrant review as a privilege-escalation foothold.

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Suspicious Google Cloud Function Create or Update Triggering Build
Pivot detection · T1078.004 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.