Legitimate app breaks popular encryption systems

Lincoln Spector

Conventional wisdom has been that files protected with good encryption can’t be cracked.

But a new, $300, wizard-driven app can unlock BitLocker-, PGP-, and TrueCrypt-encrypted files, folders, and drives — no matter how strong a password you’re using.

It’s the sort of story that could keep you up at night. Last month, Elcomsoft released the Elcomsoft Forensic Disk Decryptor (EFDD; more info), a program that opens encrypted files without trying to guess your password or attack it with brute force (Wikipedia info). In fact, the actual password is effectively irrelevant. A long, random string such as bS2f#[voIT+?@=Uq3a,.B provides no better protection against EFDD than would “password” or “12345.”

That’s the bad news. The good news? EFDD works only within a limited set of conditions — and those conditions are actually fairly easy to avoid. And it’s not as if just anyone could put down $300 and use EFDD to quickly crack encrypted data. Although it’s wizard-driven, EFDD is not all that easy to use.

Encryption cracking without guessing passwords

First, it’s important to note that products such as EFDD serve a legal, legitimate purpose. If a user has forgotten his or her password, these forensic programs can restore access to otherwise lost data. If an employee purposely or accidentally locks a company out of its critical business files, password crackers are a perfectly legitimate recovery tool.

Other examples of legitimate uses for EFDD-like applications include Windows’ own Encrypted File System (EFS) — an encryption tool I don’t recommend. Windows automatically decrypts EFS-encrypted files when they’re opened (provided you’re properly signed in to the OS.) The process is so transparent, you can forget that you have encrypted files. Then, when your computer dies or you have to reinstall Windows, you suddenly discover your files are inaccessible. Microsoft provides a fix, but you need to have prepared for its use ahead of time.

An acquaintance was inadvertently locked out of his EFS-encrypted files when his PC died. When he plugged the hard drive into another computer via a USB adapter, he had an unpleasant surprise: his files were no longer accessible. He was lucky, however; using another Elcomsoft forensic product, Advanced EFS Data Recovery (info), he eventually unlocked his files. But a thief in possession of that hard drive could have done the same thing.

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All Windows Secrets articles posted on 2013-02-07:

Lincoln Spector

About Lincoln Spector

Lincoln Spector writes about computers, home theater, and film and maintains two blogs: Answer Line at PCWorld.com and Bayflicks.net. His articles have appeared in CNET, InfoWorld, The New York Times, The Washington Post, and other publications.