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Windows 11 BitLocker Bypassed to Extract Encryption Keys (gbhackers.com)

submitted 5 days ago by [email protected] to c/[email protected]

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An attacker with physical access can abruptly restart the device and dump RAM, as analysis of this memory may reveal FVEK keys from recently running Windows instances, compromising data encryption.

The effectiveness of this attack is, however, limited because the data stored in RAM degrades rapidly after the power is cut off.

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[–] Limonene 22 points 5 days ago (9 children)

A "cold boot" attack. These have been around for a while.

The degredation is not a huge barrier. Spraying inverted canned air can cool the DRAM enough to preserve it for a little while, even long enough to switch it to a new motherboard. Whenever the motherboard is powered, the DRAM is being refreshed, so won't degrade. A few bits lost is no fatal flaw, since most cold boot attack algorithms search for long key schedules, not just the key.

Bitlocker is extra vulberable because it stores the key in the TPM and requires no password to boot. An attacker can extract the key even if the computer is off when they get it.

[–] [email protected] 9 points 5 days ago* (last edited 5 days ago) (3 children)

What's the advantage of disk encryption if you don't require a password to boot? Couldn't you just boot the device and extract the data using Explorer anyway?

[–] Limonene 4 points 5 days ago (1 children)

I assume they think the Windows login password will keep them safe. I don't know. But many corporate computers (several I've been forced to use) do use Bitlocker without a password.

[–] [email protected] 2 points 4 days ago

Yeah, that's only going to protect from drive theft, which I guess makes disposal easier?

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