The Trojan Pull Request | AltSecCON 2026

BLUF: This presentation details the "Trojan Pull Request" attack, where adversaries exploit CI/CD pipelines via malicious pull requests to gain root access and hijack cloud identities, emphasizing that business logic flaws in pipeline configuration are more dangerous than traditional bugs 7:31.

Key Takeaways:
• Attackers prefer stealthy code injection over brute force, targeting business logic errors in open-source projects to gain initial access 2:13.
• The core vulnerability lies in using pull_request_target with unsafe checkout, which allows attacker-uploaded code to execute with the repository's high-privileged credentials 4:54.
• By obtaining a root shell in the runner, attackers can query the OIDC token endpoint to impersonate the trusted internal runner, bypassing external network monitoring 9:40.
• AWS IAM policies often use wildcards that accept tokens from any repo within an organization, allowing the attacker to assume administrative roles 12:52.
• To prevent this, organizations should separate untrusted code execution from privileged environments and strictly configure IAM trust policies 24:54.

The attack demonstrates how velocity-driven development choices can create significant security gaps, requiring rigorous pipeline hardening to maintain cloud security.

Sources:

• 7:31 Importance of showing impact beyond simple bug reporting
• 2:13 Attacker mindset and preference for code injection
• 4:54 Vulnerability of pull_request_target configuration
• 9:40 Exploiting OIDC tokens for cloud identity hijacking
• 12:52 Risks of wildcard IAM trust policies
• 24:54 Mitigation strategies including separate workflows