Decryption tool available for TeslaCrypt ransomware that targets games

Security researchers found that decryption keys can be recovered from systems infected with TeslaCrypt

Some users whose computers have been infected with a ransomware program called TeslaCrypt might be in luck: security researchers from Cisco Systems have developed a tool to recover their encrypted files.

TeslaCrypt appeared earlier this year and masquerades as a variant of the notorious CryptoLocker ransomware. However, its authors seemed intent on targeting gamers in particular.

Once installed on a system, the program encrypts files with 185 different extensions, over 50 of which are associated with computer games and related software, including user-generated content like game saves, maps, profiles, replays and mods.

In the ransom note displayed on infected computers, TeslaCrypt claims to be using asymmetric encryption based on the RSA public-key cryptosystem. If true, this would mean that the data is encrypted with a public key stored on the system and can only be decrypted with a private key held by the attackers.

However, after analyzing the malicious program, researchers from Cisco's Talos Group found that it actually uses a symmetric encryption algorithm called AES. This algorithm uses the same key for both encryption and decryption.

Some versions of TeslaCrypt store the encryption key in a file called key.dat on infected systems, but others delete it after they finish encrypting files and store an encrypted version of it in a different file called RECOVERY_KEY.TXT, the Cisco researchers said Monday in a blog post.

The researchers developed a tool that can decrypt files affected by TeslaCrypt if the master encryption key is still found in key.dat. Users should save a copy of this file as soon as they realize that their computers have been infected with TeslaCrypt so they can later use it with the Cisco tool.

The Cisco researchers are still working on reverse-engineering the algorithm used by attackers to restore the master encryption key based on the recovery key. If successful, this will allow them to also decrypt files from versions of TeslaCrypt that delete the master key from the key.dat file when the encryption operation is done.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags malwareencryptionCisco Systems

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

Lucian Constantin

IDG News Service
Show Comments

Father’s Day Gift Guide

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Luke Hill

MSI GT75 TITAN

I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Laura Johnston

MSI GS65 Stealth Thin

If you can afford the price tag, it is well worth the money. It out performs any other laptop I have tried for gaming, and the transportable design and incredible display also make it ideal for work.

Andrew Teoh

Brother MFC-L9570CDW Multifunction Printer

Touch screen visibility and operation was great and easy to navigate. Each menu and sub-menu was in an understandable order and category

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Featured Content

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?