New WireTap Attack Extracts Intel SGX ECDSA Key via DDR4 Memory-Bus Interposer

Researchers from Georgia Institute of Technology and Purdue University have demonstrated that SGX protections can be bypassed on DDR4 systems by a memory-bus interposer, showing how an attacker could passively decrypt data and extract an ECDSA signing key. The study, disclosed on 1 October 2025, describes a device—codenamed WireTap—that sits between the CPU and memory to observe memory traffic, enabling the extraction of Intel SGX attestation keys from a machine in fully trusted status.

The work says the interposer can undermine SGX’s security by exploiting deterministic memory encryption to recover keys used by Intel’s QE, effectively letting an attacker masquerade as genuine SGX hardware and peek at data. The authors note WireTap complements a prior Battering RAM approach; while the former targets confidentiality, the latter focuses on integrity, and both indicate SGX and SEV are vulnerable to memory interposition.

While WireTap costs about $1,000 to set up, a related, low-cost Battering RAM method can be cheaper than $50. Intel has said the exploit falls outside its threat model, recommending secure physical environments and noting that AES-XTS memory encryption provides only limited confidentiality with no integrity or anti-replay protection against physical access.