The Real Menace of Cloning Attacks on SGX Applications

Trusted Execution Environments (TEEs) are gaining popularity as an effective means to provide confidentiality in the cloud. TEEs, such as Intel SGX, suffer from so-called rollback and cloning attacks (often referred to as forking attacks). Rollback attacks are enabled by the lack of freshness guarantees for sealed data; cloning attacks stem from the inability to determine if other instances of an enclave are running on the same platform. While rollback attacks have been extensively studied by the community, cloning attacks have been, unfortunately, less investigated. To address this gap, we extensively study and thoroughly analyze the susceptibility of 72 SGX-based proposals to cloning attacks. Our results show that roughly 20% of the analyzed proposals are insecure against cloning attacks-including those applications that rely on monotonic counters and are, therefore, secure against rollback attacks.