Intel processors / SGX (load value injection): MULTI-TENANT ISOLATION: The inverse of Meltdown: instead of leaking data

Impact

MULTI-TENANT ISOLATION: The inverse of Meltdown: instead of leaking data out of the enclave, the attacker injects a value into a faulting load inside the victim enclave and steers its transient execution into attacker-chosen gadgets. That gives enclave-secret extraction from outside the enclave, again breaking the SGX guarantee against a privileged host.

Who can reach it

Local privileged code on the host targeting a victim enclave on the same machine.

What to do

SGX SDK/PSW update that inserts LFENCE serialisation in enclave code, plus microcode. The software mitigation requires recompiling enclaves with the patched SDK - a code change for whoever ships the enclave, not something the operator can apply unilaterally - and it carries a heavy performance cost. Microcode is late-loadable at boot; enclave recompilation is not. Re-attestation required.

References