Google ADK Agent-to-Agent Attack: Privilege Boundary Breakdown Calling Privileged CI Workflows from Low-Privilege Triage Agents

Short summary

Pillar Security demonstrated an agent-to-agent privilege escalation attack on Google's ADK repository where prompt injection in an external PR tricks a low-privilege triage agent into triggering high-privilege Gemini CI workflows. The attacker spoofs reviews, approvals, and labels using the GITHUB_TOKEN, making malicious PRs appear legitimately reviewed to human maintainers. Google has mitigated the issue.

• •Prompt injection in PRs can trick low-privilege AI agents into triggering privileged CI/CD workflows
• •Attack spoofs GitHub reviews and approvals using stolen GITHUB_TOKEN, fooling human maintainers
• •Fix requires treating agent output as untrusted, signed capabilities for agent hand-offs, and short-lived App tokens instead of collaborator PATs

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