Security? What security? Say hello to 'LVI' (Load Value Injection), a new class of' transient-execution attacks' exploiting flaws in modern processors and it defeats all existing countermeasures.
Oh hell. This comes shortly after Intel had another one announced that was 'unfixable', plus one for AMD too and now this all in the space of a month. Rough time right now, for Intel specifically on this one.
LVI turns previous data extraction attacks around, like Meltdown, Foreshadow, ZombieLoad, RIDL and Fallout, and defeats all existing mitigations. Instead of directly leaking data from the victim to the attacker, we proceed in the opposite direction: we smuggle — "inject" — the attacker's data through hidden processor buffers into a victim program and hijack transient execution to acquire sensitive information, such as the victim’s fingerprints or passwords.
It's serious, as they claim the difficulty in solving it is much harder than all previous attacks and will require some computationally expensive software patches. They say it may "slow down Intel SGX enclave computations 2 up to 19 times"—ouch.
They give a quick 4-step process to LVI:
- Poison a hidden processor buffer with attacker values.
- Induce a faulting or assisted load in the victim program.
- The attacker's value is transiently injected into code gadgets following the faulting load in the victim program.
- Side channels may leave secret-dependent traces, before the processor detects the mistake and rolls back all operations.
You can also see a demo video below:
What about AMD? Well, their current assessment is that LVI only applies to Intel processors that have SGX tech. However, it can affect any other processor if they're vulnerable to a Meltdown-type data leakage.
See more about it on the official site and the research paper is found here. You can see the official Intel security advisory here, plus a list of affected processor products here. Additionally, Intel have their own deep dive here.