TeslaCrypt victims can now decrypt their files for free

Security shocker: Ransomware creators give researchers the master decryption key

Victims of the widespread TeslaCrypt ransomware are in luck: Security researchers have created a tool that can decrypt files affected by recent versions of the malicious program.

Surprisingly, the TeslaCrypt creators themselves helped the researchers.

TeslaCrypt first appeared in early 2015 and stood out by targeting game-related user content, such as save files and custom maps, in addition to personal documents and pictures -- 185 different file extensions in total.

The program had some moderate success in the beginning, earning its creators $76,522 in less than two months. However, in April 2015, researchers from Cisco Systems discovered a flaw in the ransomware program that allowed them to create a decryption tool for some of its variants.

The number of TeslaCrypt attacks spiked in December and starting with version 3.0.1 of the program, which appeared in March, all encryption flaws were fixed and the existing decryption tools were rendered ineffective. That lasted until Wednesday.

Researchers from security vendor ESET have recently managed to obtain a copy of TeslaCrypt's master key, allowing them to create a new decryption tool that is capable of recovering files affected by the newer versions of TeslaCrypt (3.0 and higher). They didn't do this by exploiting a vulnerability in the program or its command-and-control servers, but by asking its creators for it.

"Recently, TeslaCrypt’s operators announced that they are wrapping up their malevolent activities," the ESET researchers said in a blog post. "On this occasion, one of ESET’s analysts contacted the group anonymously, using the official support channel offered to the ransomware victims by the TeslaCrypt’s operators, and requested the universal master decryption key. Surprisingly, they made it public."

The tool can recover TeslaCrypt-encrypted files whose extension was changed to .xxx, .ttt, .micro and .mp3, as well as those whose extension hasn't been modified. Instructions on downloading and using the tool can be found on ESET's support website.

Join the CSO newsletter!

Error: Please check your email address.

More about CiscoESET

Show Comments

Featured Whitepapers

Editor's Recommendations

Solution Centres

Stories by Lucian Constantin

Latest Videos

  • 150x50

    CSO Webinar: The Human Factor - Your people are your biggest security weakness

    ​Speakers: David Lacey, Researcher and former CISO Royal Mail David Turner - Global Risk Management Expert Mark Guntrip - Group Manager, Email Protection, Proofpoint

    Play Video

  • 150x50

    CSO Webinar: Current ransomware defences are failing – but machine learning can drive a more proactive solution

    Speakers • Ty Miller, Director, Threat Intelligence • Mark Gregory, Leader, Network Engineering Research Group, RMIT • Jeff Lanza, Retired FBI Agent (USA) • Andy Solterbeck, VP Asia Pacific, Cylance • David Braue, CSO MC/Moderator What to expect: ​Hear from industry experts on the local and global ransomware threat landscape. Explore a new approach to dealing with ransomware using machine-learning techniques and by thinking about the problem in a fundamentally different way. Apply techniques for gathering insight into ransomware behaviour and find out what elements must go into a truly effective ransomware defence. Get a first-hand look at how ransomware actually works in practice, and how machine-learning techniques can pick up on its activities long before your employees do.

    Play Video

  • 150x50

    CSO Webinar: Get real about metadata to avoid a false sense of security

    Speakers: • Anthony Caruana – CSO MC and moderator • Ian Farquhar, Worldwide Virtual Security Team Lead, Gigamon • John Lindsay, Former CTO, iiNet • Skeeve Stevens, Futurist, Future Sumo • David Vaile - Vice chair of APF, Co-Convenor of the Cyberspace Law And Policy Community, UNSW Law Faculty This webinar covers: - A 101 on metadata - what it is and how to use it - Insight into a typical attack, what happens and what we would find when looking into the metadata - How to collect metadata, use this to detect attacks and get greater insight into how you can use this to protect your organisation - Learn how much raw data and metadata to retain and how long for - Get a reality check on how you're using your metadata and if this is enough to secure your organisation

    Play Video

  • 150x50

    CSO Webinar: How banking trojans work and how you can stop them

    CSO Webinar: How banking trojans work and how you can stop them Featuring: • John Baird, Director of Global Technology Production, Deutsche Bank • Samantha Macleod, GM Cyber Security, ME Bank • Sherrod DeGrippo, Director of Emerging Threats, Proofpoint (USA)

    Play Video

  • 150x50

    IDG Live Webinar:The right collaboration strategy will help your business take flight

    Speakers - Mike Harris, Engineering Services Manager, Jetstar - Christopher Johnson, IT Director APAC, 20th Century Fox - Brent Maxwell, Director of Information Systems, THE ICONIC - IDG MC/Moderator Anthony Caruana

    Play Video

More videos

Blog Posts