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Computer scientists have discovered a novel way to bypass the encryption used in programs like Microsoft's BitLocker and Apple's FileVault and view the contents of supposedly secure files.

In a paper [pdf] published on Thursday that could prompt a rethinking of how to protect sensitive data, the researchers describe how they can extract the contents of a computer's memory and discover the secret encryption key used to scramble files.

"There seems to be no easy remedy for these vulnerabilities," the researchers say. "Simple software changes are likely to be ineffective; hardware changes are possible but will require time and expense; and today's Trusted Computing technologies appear to be of little help because they cannot protect keys that are already in memory. The risk seems highest for laptops, which are often taken out in public in states that are vulnerable to our attacks. These risks imply that disk encryption on laptops may do less good than widely believed."

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said by OneHeart :

TrueCrypt is also on the list.

said by C|Net :

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The researchers say their technique works against Apple's FileVault, the BitLocker Drive Encryption feature included in the Enterprise and Ultimate versions of Windows Vista, the open-source product TrueCrypt, and the dm-crypt subsystem built into Linux kernels starting with 2.6.

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said by C|Net :

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So what are the countermeasures? As I noted above, shutting down the system, zeroing memory on boot, and unmounting encrypted volumes are some options. The paper suggests others, including limiting booting from network or removable drives, better methods of putting a computer to sleep (perhaps involving encrypting the portions of memory with the keys to the file system), recomputing keys when they're needed to avoid keeping copies in memory, and hardware changes such as tamperproof or encrypting RAM.

There is one irony here. One Princeton Ph.D. student, Joseph Calandrino, is listed as having "performed this research while under appointment to the Department of Homeland Security." Because this research lets them bypass filesystem encryption in some cases, police agencies are the most obvious and immediate beneficiaries of this research.

As early as 1984, the FBI Laboratory began developing computer forensics hardware. And we know from the Scarfo, Forrester-Alba, and Boucher cases how intent federal police agencies are in trying to find ways to circumvent the privacy that encryption provides. If the feds didn't know about these techniques already--remember, they were years ahead of everyone else in inventing public key cryptography--today will be a very good day for Homeland Security.

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said by mikenolan7 :

There is a software memory wiper called SMEM. It was included in older versions of the System Rescue CD. I haven't downloaded a copy of System Rescue lately, so I don't know if it is still one of their packages.

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SMEM from the THC-Secure Deletion Tools ( see »www.thc.org/releases.php?q=delete ) does a secure overwriting of unused memory (RAM)

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said by amungus :

I'm curious about one thing... why wouldn't Vista's "address space randomization" (whatever it's called...) do any good here? Should that not make it more difficult to find the keys? Could there be any way to sufficiently randomize it such that an analyst couldn't tell which pieces to put back together? Granted, that'd probably take some serious work, but it seems like it might be one way of making things more difficult...

Executives of Microsoft said BitLocker has a range of protection options that they referred to as “good, better and best.” ....
...The Princeton researchers acknowledged that in these advanced modes, BitLocker encrypted data could not be accessed using the vulnerability they discovered.

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To reconstruct an AES key, we treat the decayed key schedule as an error correcting code and find
the most likely values for the original key. Applying this method to keys with 10% of bits decayed, we can
reconstruct nearly any 128-bit AES key within a few seconds. We have devised reconstruction techniques
for AES, DES, and RSA keys, and we expect that similar approaches will be possible for other cryptosys-
2
tems; we have correctly recovered keys from several popular disk encryption products.

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said by darthboy :

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With regards to the posts saying that a computer's POST will wipe out RAM contents:
that's presuming the malicious person plugs the RAM into another computer.

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Surely there're standalone devices that are able to extract the RAM contents?

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However, if a malicious person has physical access to your computer, it's no longer your computer anywayz.

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