Encryption goof fixed in TorrentLocker file-locking malware

A new variant of TorrentLocker fixes a problem that allowed encrypted files to be freed

The developers of a type of malicious software that encrypts a computer's files and demands a ransom have fixed an error security experts said allowed files to be recovered without paying.

The malware, called TorrentLocker, popped up last month, targeting users in Australia, according to iSight Partners, a security consultancy. It now appears to be also geo-targeting victims in the U.K.

TorrentLocker's developers ironically made a similar mistake as the creators of another ransomware program, CryptoDefense. Researchers found earlier this year that CryptoDefense left a decryption key on a person's computer, although the error was soon fixed.

Earlier this month, researchers with the consultancy Nixu found that TorrentLocker used the same keystream to encrypt all of a computer's files. That was a mistake, as a keystream should never be used more than once, according to a writeup on the SANS Institute blog.

"As the encryption was done by combining the keystream with the plaintext file using the XOR operation, we were able to recover the keystream used to encrypt those files by simply applying XOR between the encrypted file and the plaintext file," they wrote.

With the error out in the open, it was only a matter of time before it was fixed.

Richard Hummel, a senior technical analyst with iSight, wrote that a variant of TorrentLocker without that bug has now been found, which shows the "extremely high pace of innovation of our collective adversaries."

The latest version also scans profiles in the Thunderbird email client for email addresses and passwords, he wrote. "This will almost certainly be used to further the spam campaign for TorrentLocker," he wrote.

TorrentLocker asks for US$500 to unlock the files, payable in bitcoin. Hummel wrote that although the percentage of people who pay is low, a look at the bitcoin address associated with TorrentLocker showed that the attackers are making "many bitcoins," he wrote.

Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Tags NixuSANS InstitutesecurityiSight Partnersmalware

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jeremy Kirk

IDG News Service
Show Comments

Most Popular Reviews

Latest News Articles


GGG Evaluation Team

Kathy Cassidy


First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni


For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell


The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi


The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott


My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?