Wednesday, March 11th 2020
Intel Processors Hit with LVI Security Vulnerabilities, Mitigation Hits Performance Hard
A new class of security vulnerabilities affect Intel processors, which can cause them to leak out sensitive information if probed in a certain way, but that's not the worst news for Intel and its users. The software- or firmware-level mitigation for this vulnerability can inflict performance reductions "ranging from 2x to 19x," according to a report by The Register. A full mitigation for the new Load Value Injection (LVI) class of vulnerabilities requires Intel to redesign software compilers. The vulnerability is chronicled under CVE-2020-0551 and Intel-SA-00334. It is not a remote code execution threat, however, it puts multi-tenant machines, such as physical servers handling multiple tenants via virtual servers.
"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," the reasearchers write in the abstract of their paper describing the vulnerability. Anti-virus manufacturer BitDefender independently discovered LVI and shared its study with Intel. The company could publish its findings in February. Additional technical details are found in the group's website here.
Many Thanks to biffzinker for the tip.
Source:
The Register
"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," the reasearchers write in the abstract of their paper describing the vulnerability. Anti-virus manufacturer BitDefender independently discovered LVI and shared its study with Intel. The company could publish its findings in February. Additional technical details are found in the group's website here.
92 Comments on Intel Processors Hit with LVI Security Vulnerabilities, Mitigation Hits Performance Hard
2. What the heck is "spoofing memory"? Are you overwriting memory for something else? Don't you at least need root access to the machine to do that? Something like this would require ring-0 access on the VM host (not even ring -1 access from a VM,) to do something like that across bounds of a VM.
3. Ok, but do you have control to do that from a VM?
4. Ok, but still not sure if you can do this from a VM.
5. How do you plan on preventing that from happening? If it's a server, that's out of your control.
6. Once again, what is this "spoofing" you speak of? Writing to cache has the same kinds of constraints as writing to main memory and you're probably not doing this without ring 0 access.
7. What are you doing that forces the CPU to read from the next page page, word, or tag in cache? An access violation shouldn't scan for another item in cache, it should generate a machine check exception.
8. :wtf:
We should still keep comparing the two in my opinion cause lvi, as stated before, is pretty much theoretical only. It is a duel between amd spectre and intel spectre-class vulnerabilities.
Meltdown in particular seems to be a straightforward bug in Intel's design. One that is complex to abuse but still a bug.