Silk Road forums
Discussion => Security => Topic started by: quietguy on December 21, 2012, 06:58 pm
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[Clearnet] http://www.informationweek.com/security/encryption/forensic-tool-cracks-bitlocker-pgp-truec/240145127
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(pasting for convenience)
A new software tool, Elcomsoft Forensic Disk Decryptor, promises to decrypt encryption containers created using BitLocker, PGP and TrueCrypt.
The software from ElcomSoft -- a Russian provider of encryption-cracking software and other digital forensic tools -- accomplishes the feat not by cracking the containers themselves, but rather by exploiting the fact that once the containers are accessed, the decryption passwords get stored in computer memory. The software is designed to be used by digital forensic investigators -- for example, when investigating suspected insider theft incidents.
"BitLocker, PGP and TrueCrypt set [an] industry standard in the area of whole-disk and partition encryption," said ElcomSoft CEO Vladimir Katalov in a blog post. "All three tools provide strong, reliable protection, and offer a perfect implementation of strong crypto." As a result, he said that if a user of those tools picks a long, complex password, cracking the encryption container outright would likely be impossible.
[ Forensics software can be a crucial tool in busting the bad guys. Read Cracking Bin Laden's Hard Drives. ]
One encryption container Achilles heel, however, happens when the containers get accessed on a computer. "No one likes typing their long, complex passwords every time they need to read or write a file," said Katalov. "As a result, keys used to encrypt and decrypt data that's being written or read from protected volumes are kept readily accessible in the computer's operating memory. Obviously, what's kept readily accessible can be retrieved near instantly by a third-party tool."
What's needed first, however, is a memory dump, which can be grabbed either using forensic tools, or via a Firewire attack, even if a computer is in hibernation or sleep mode. The Elcomsoft tool then attempts to extract the encryption keys from that dump. "The new product includes algorithms allowing us to analyze dumps of computers' volatile memory, locating areas that contain the decryption keys," Katalov said. "Sometimes the keys are discovered by analyzing byte sequences, and sometimes by examining crypto containers' internal structures. When searching for PGP keys, the user can significantly speed up the process if the exact encryption algorithm is known."
But there's one big caveat when grabbing the needed memory dumps: The targeted encryption containers must be mounted to the computer. "It's important that encrypted volumes are mounted at the time a memory dump is obtained or the PC goes to sleep; otherwise, the decryption keys are destroyed and the content of encrypted volumes cannot be decrypted without knowing the original plain-text password," said Katalov.
The three encryption containers targeted by the software comprise some of the most-used file encryption tools on the market. Microsoft's BitLocker To Go, for example, allows data on removable devices to be encrypted and is included with some premium versions of Windows 7 and Vista, as well as Windows 8.
TrueCrypt, meanwhile, is well-regarded open source data encryption software that currently runs on Windows 7, Vista and XP, as well as Mac OS X and Linux systems. Finally, PGP -- which stands for Pretty Good Privacy -- is available from Symantec, which acquired PGP in 2010.
Elcomsoft also has added plug-ins for TrueCrypt and BitLocker To Go to its Distributed Password Recovery software, which allows users to subject encryption containers to a variety of brute-force attack techniques, as well as a dictionary, password mask and permutation attacks.
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Sounds like you need to unmount encrypted drives when you are done using them to destroy that password in memory. That or use a UBS drive you take with you.
Modzi
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I'm no computer forensics expert, but would erasing the Windows swap file at the end of each session, say 7 or so overwrites, defeat this type of thing?
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I would assume to generate such ideal conditions would be very costly for LE as it would require a skilled computer hacker and constant monitoring to try and catch you in action. At most, this treatment is probably only reserved to sellers. I think the majority of educated SR users are safe against this since I assume most of us don't even have the incriminating files on our system (i.e. flash drive) and therefore no mounted encrypted/decrypted volumes. As well as not using routers protected by WEP or WPS vulnerability (update your routers firmware if its old). If LE where to confiscate a system with an encrypted volume present but not mounted, it will still be difficult for LE to get you to decrypt the volume as you can plea the fifth setting you up for a condition where only a judge can force you to decrypt it and that's jumping into constitutional rights so it's unknown what the judge will rule.
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I'm no computer forensics expert, but would erasing the Windows swap file at the end of each session, say 7 or so overwrites, defeat this type of thing?
No. WIping swap is nevertheless still a good idea, however. Forensic examiners can glean all kinds of information from swap files, which is the main reason that you either:
1) Turn swap off (not sure how easy this is to do in Windows -- swapoff -a will do it in Linux. )
2) Encrypt your swap file; or
3) Wipe your swap file on shutdown.
NC
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Sounds like you need to unmount encrypted drives when you are done using them to destroy that password in memory. That or use a UBS drive you take with you.
Modzi
Exactly correct. What people all too often forget is that drives, even when full-disk encrypted, are safe only when the disks are dismounted. As long as the drives are mounted, they can be accessed the same as any other unencrypted volumes.
NC