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submitted 4 months ago by moe90@feddit.nl to c/technology@lemmy.world
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[-] MonkderVierte@lemmy.ml 5 points 4 months ago

Any exploit that gives root

Same in green. If the attacker has physical access or root, you have lost already.

[-] Blue_Morpho@lemmy.world 2 points 4 months ago* (last edited 4 months ago)

This AMD firmware exploit is different. Yes if an exploit gets your computer you have lost. But it happens to thousands every day. A virus scan will detect it and an OS wipe will clean it.

This AMD exploit means the exploit lives inside the CPU firmware. It can't ever be detected or removed by normal means because the CPU itself is compromised. (Unless you have the hardware to pull physical signals off your dram chips.)

In the past even normal OS patches would clear out any virus's lingering in the PC population. Now you could be compromised and never know or be able to do anything about it.

[-] lurch@sh.itjust.works 6 points 4 months ago

A virus scan will detect it and an OS wipe will clean it.

This only works before the malware has been executed and only if the malware scanner knows it. Often Antivirus can block access to the malware, so it can't be executed.

If it has been executed, the PC needs to be shut down and all writable mediums connected wiped (including boot sectors and EFI), maybe even the BIOS reset, if it can be updated, to be 100% clean. If you can't do this, you have to toss the PC in the trash.

If the PC is not shut down, the malware could still survive in RAM and re-install its files or download something else, eg. a remote shell or rootkit.

These processor security flaws just extend this to the CPU firmware, meaning you need to reset this too, after malware has been executed on the PC. If you just downloaded it and the antivirus blocked and deleted it, you're still safe.

If it got executed and you or a technician can't remove it from the CPU, you have to toss the PC in the trash, just like you already had to if you can't reset a malware that flashed itself into an updatable BIOS, for example.

[-] Blue_Morpho@lemmy.world 0 points 4 months ago

Offline virus scanners are standard. That's always how you detect if you have been infected. Bios viruses are detected and removed by standard anti-virus software.

[-] lurch@sh.itjust.works 2 points 4 months ago

BIOS and UEFI bootkits require special vendor tools and vendor signed firmware binaries to overwrite the SPI memory. Standard anti-virus software can not remove them, once they have been installed.

[-] Blue_Morpho@lemmy.world 1 points 4 months ago

You are right, you patch your bios with a vendor program. However regular virus scanners will detect it and motherboard manufacturers provide bios flashing tools. But AMD has said they will not provide firmware tools for their old CPUs.

this post was submitted on 17 Aug 2024
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