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Downfall Attacks

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Re: Downfall Attacks

#21
post #4

From FAQ: [Q] How long have users been exposed to this vulnerability? [A] At least nine years. The affected processors have been around since 2014. Amazing how these vulnerabilities sit around unnoticed for years and then it takes two weeks for someone to code up an exploit.

All a publication indicates is that a white/grey hat researcher has discovered the vulnerability. There is no way to know if or how many times the same flaw has been exploited by less scrupulous parties in the interim.

Re: Downfall Attacks

#22
> [Q] Should other processor vendors and designers be concerned?

> [A] Other processors have shared SRAM memory inside the core, such as hardware register files and fill buffers. Manufacturers must design shared memory units with extra care to prevent data from leaking across different security domains and invest more in security validation and testing.

Not sure what to make of this wording. Thinly veiled threat? Hint that other embargoes are in place?

Re: Downfall Attacks

#23

Stop. Releasing. Attack research. Without. Detection strategies.

That doesn't make any sense. You want to prep a fix for distribution ASAP, and release it so people can be protected from it as soon as possible.

Also many attacks are not really feasible to detect if it's happened - that's like trying to know if the mailman read your postcard.

You can develop executable scanning techniques, but people are a lot more concerned about preventing it in the first place than catching it in the act. Why would you leave people vulnerable so they can watch data get stolen - instead of just fixing the issue?

Re: Downfall Attacks

#25

I'm getting annoyed with all of these yawning security holes in Intel's CPUs. I'm tempted to replace my Intel MacBook Pro with an Apple Silicon model sooner than I normally would.

I'm not sure what evidence there is to think that Apple's chips are any better. And that's not really a dig at Apple; these are just very complicated devices and especially with the optimizations that CPUs need to make to run today's software with acceptable performance, it can become very hard to foresee all possible attacks and vulnerabilities.

Re: Downfall Attacks

#26
post #9
post #7

Earlier quoted context omitted.

If I'm reading this right, the caveat is that the exploit only lets you read registers that have been saved for context-switching. So, in order to extract data, that data must be in constant active use (i.e. loaded in a register) at the time of the attack.

Would environmental variables be something that shows up in context-switching?

In general, not really, but the most common string comparison instruction in x86_64 leaves the last character of one of the strings being compared with the other one just being a pointer into the C-style string.

Re: Downfall Attacks

#27
post #22

> [Q] Should other processor vendors and designers be concerned? > [A] Other processors have shared SRAM memory inside the core, such as hardware register files and fill buffers. Manufacturers must design shared memory units with extra care to prevent data from leaking across different security domains and invest more in security validation and testing. Not sure what to make of this wording. Thinly veiled threat? Hin…

It's not super revelatory given all the other Meltdown/Spectre bugs. I wouldn't read too much into it.

Re: Downfall Attacks

#29
Does anyone know what type of workloads this effects the performance of the most? Is this specialty-type of workloads or are general webserver/database/coding/compiling/gaming/desktop usages effected?

Re: Downfall Attacks

#30

Stop. Releasing. Attack research. Without. Detection strategies.

Not all systems are equally exposed, and while there is no universal low level fix many systems can be redesigned at a higher level to reduce exposure.
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