Epic's EAC2 v2 Linux implementation faces potential bypass via TPM manipulation

Matthew Garrett has identified potential vulnerabilities in Epic's upcoming Easy Anti-Cheat (EAC2) v2 for Linux. The system relies on eBPF monitoring, Secure Boot, and TPM-based remote attestation to ensure kernel integrity. However, the proposed security measures can be circumvented by resetting the physical TPM module or using a USB-to-SPI bridge to present a legitimate TPM with falsified measurements to the system.

Technical bypass methods for EAC2 v2

• TPM Reset: On many desktop boards, the TPM is a plug-in module that can be reset to its initial state by briefly grounding the reset pin, allowing userland to write arbitrary measurements.
• External TPM via SPI: Users can use a USB-to-SPI bridge to connect an external TPM module, directing the kernel to use this device instead of the motherboard TPM.
• Kernel Manipulation: Since the security relies on eBPF monitoring within the kernel, a modified kernel can be used to lie to the eBPF code and replay expected boot measurements to the TPM.
• Remote Attestation Weakness: The mechanism relies on the assumption that a TPM is tied to a specific system, which is difficult to enforce on consumer hardware compared to enterprise environments.

Why it matters

While these bypasses require hardware intervention or kernel modification, they highlight the difficulty of implementing robust anti-cheat measures on open platforms like Linux.