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Just about every Windows and Linux device vulnerable to new LogoFAIL firmware attack
(arstechnica.com)
this post was submitted on 07 Dec 2023
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Can anyone explain to me if this is an actual risk outside a highly controlled environment? AFAIK, it's a pretty non-casual thing to change the UEFI boot logo, so wouldn't that make this pretty hard to actually pull off?
The article quoted the researchers who indicated it can be done with remote access by using other attack vectors. This is because most UEFI systems store the logo on disk in the EFI system partition. It doesn't need to do anything crazy like compile and flash a modified firmware. All it needs to do is overwrite the logo file on disk.
If you have access to directly write to arbitrary disk locations you already have full control. Why bother with overwriting the logo file with a malicious payload if you can just overwrite the actual kernel...
Because this can persist beyond an OS rebuild or patch. You infect the BIOS and you're on the device until the BIOS is free reflashed. And who ever does that?
Or until you overwrite that malicious logo again?
No. The logo is loaded, runs in BIOS context and is able to modify the BIOS. Now it's embedded and the logo is irrelevant.
Due to Secure Boot (if it actually enabled since there are some bogous implementations) this can be prevented. If I understand it correctly, LogoFAIL bypasses this security measure and enables loading unsigned code.
This is what I'm wondering
Ah, that's much easier than I thought. I guess I'm horrible out of date on my "messing with BIOS" knowledge
If it's on the disk, why doesn't the image get removed when I erase all partitions? Does the firmware put it back?
If I'm understanding this correctly this isn't necessarily the very first logo that would appear but one that appears as the firmware starts to boot an OS from the EFI system partition. So technically installing your OS puts the original non-malicious logo there.
It does, but if it has compromised the BIOS before that, that won't get wiped.