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Finally, we abuse Intel SGX to hide the attack entirely from the user and the operating system, making any inspection or detection of the attack infeasible It'
by peoplewindow 9y ago
Finally, we abuse Intel SGX to hide the attack entirely from the user and the operating system, making any inspection or detection of the attack infeasible
It's unfortunate that academics feel OK about making misleading statements in this space. SGX enclaves must be signed by Intel to work, so I doubt very much that they abused SGX in this way. What they mean is that they could have done, if they had got Intel to approve their attack, which is a pretty freaking huge caveat.
- ameliaquining 9y agoNo, the attack doesn't require Intel to sign the attacker's code. It works by abusing SGX's tamper detection, which hangs the machine if a forbidden memory region has been written to. If you can trigger such forbidden writes repeatedly (which is what Rowhammer does), you can DDoS a cloud provider.
- peoplewindow 9y agoThe paper makes several claims about SGX, but the part I quoted says it uses it to hide the attack from the operating system. The "DoS a cloud by making a hang" aspect is different.
- yorwba 9y agoYes, the hardware must be signed by Intel, but the code can be anything, since the idea is to make cloud hardware trustworthy even for sensitive computations a customer might run. The researchers use the enclave in the intended way (protecting their code from interference even by privileged code) but for a malicious purpose. (Thus abusing it.) Intel will happily provide them with an attestation that the code is indeed running in a secure enclave.
- wmf 9y agoThat's how SGX probably should work and that's how everyone thought it works for years, but at the last minute Intel announced that they have to sign every enclave. https://software.intel.com/en-us/articles/intel-software-guard-extensions-product-licensing-faq https://software.intel.com/en-us/articles/intel-software-gua...