A new type of side channel attack(SGXPECTRE) against SGX enclaves revealed by security researchers that could compromise the security of SGX enclaves.
SGX is a hardware extension that provides an isolated shielded environment for software applications to run isolated from other software systems. The SGX extensions available with the recent versions of Intel processors.
Security researchers from Ohio State University discovered this new breed of the spectre attack in SGX that could allow the attackers to extract the secrets from the SGX enclaves. Researchers published a paper on how malicious programs can observe the codes executing SGX enclave.
The traditional side-channel attacks are feasible only if the enclave program already has secure dependent memory access patterns, but SGXPECTRE Attacks are more concerning and it completely compromises the security of the enclaves.
Researchers said “if the enclave code can be influenced by the programs that are running outside of enclave, the control flow of the external program can be temporarily altered to execute instructions that lead to observable cache-state changes.
“We demonstrate end-to-end attacks to show that the adversary could learn the content of the enclave memory, as well as its register values in such attacks,” researchers said.
Such as adversary observing the changes with SGX enclaves completely defeated the confidentiality guarantee that offered by SGX enclaves.
An application that implements Retpoline which allows indirect branches to be isolated from speculative execution is immune to SGXPECTRE Attacks.
Intel is to publish updates for SgxPectre on March 16th, researchers suggested specifying the minimum CPUSVN during their development.
With the vulnerable code patterns inside the SDK runtime libraries, any code developed with Intel’s official SGX SDK will be impacted by the attacks. It doesn’t matter how the enclave program is implemented.