Experts recover data encrypted by Petya ransomware
Get your data back without paying criminals


Victims of ransomware that has infected machines and prevented access to data may now be able to regain access to those files, thanks to an unidentified developer that managed to crack the malware.
The programmer, who is only known by their Twitter handle Leo_and_Stone, released the tool via code-sharing site Github. They developed the code to help their father-in-law, who's machine was infected by the malware.
The malware, which has been in circulation since March, locks up data and demands a ransom of 0.9 bitcoins (264). It arrives hidden in emails purporting to come from people looking for employment.
The malware replaces the hard drive's legitimate Mast Boot Record code. It encrypts the master file table (MFT) and display a ransom note.
What is novel about this malware is that the files are not encrypted. It is the MFT that has been changed so the operating system cannot locate data. Data recovery tools can reconstruct files, but this is not always successful.
The code developed by Leo_and_Stone means that data recovery or paying a ransom is no longer necessary. Experts from BleepingComputer.com confirmed that the method works, but it entails extracting some data from an affected hard drive.
Tim Stiller, senior systems engineer at Rapid7, told IT Pro that what is unique about Petya ransomware and this new decryption tool is the ability to recover files without paying bitcoins.
Sign up today and you will receive a free copy of our Future Focus 2025 report - the leading guidance on AI, cybersecurity and other IT challenges as per 700+ senior executives
"Many ransomware variants go to great lengths to thwart the user from decrypting the files without paying the ransom. In Petya's case, the disk was encrypted with just a single key. While the description technique for decryption can be a bit complex for some, it works," he said.
"For victims infected with Petya, this tool is very helpful at recovering their data. From the malware author's perspective, this particular decryption tool will likely prompt them to either change how the encryption functions, or shift over to a file-by-file level encryption, thus patching the ability to recover data.
"For organisations dealing with threats such as this, it is recommended that they maintain recent backups of their data and avoid opening any emails and attachments that they are unsure about. If they have any concerns, they should forward suspect emails to the security team for triage," he added.
Rene Millman is a freelance writer and broadcaster who covers cybersecurity, AI, IoT, and the cloud. He also works as a contributing analyst at GigaOm and has previously worked as an analyst for Gartner covering the infrastructure market. He has made numerous television appearances to give his views and expertise on technology trends and companies that affect and shape our lives. You can follow Rene Millman on Twitter.
-
The unseen risk in Microsoft 365: disaster recovery
Businesses that assume they’re covered for data backup could come unstuck in a time of crisis
-
Anthropic CEO Dario Amodei's prediction about AI in software development is nowhere nearly to becoming a reality
News In March, Anthropic CEO Dario Amodei claimed up to 90% of code would be written by AI within six months – his prediction hasn't quite come to fruition.
-
Prolific ransomware operator added to Europe’s Most Wanted list as US dangles $10 million reward
News The US Department of Justice is offering a reward of up to $10 million for information leading to the arrest of Volodymyr Viktorovych Tymoshchuk, an alleged ransomware criminal.
-
Jaguar Land Rover “did the right thing” shutting down systems to thwart cyber attack
News The attack on Jaguar Land Rover highlights the growing attractiveness of the automotive sector
-
Ransomware attack on IT supplier disrupts hundreds of Swedish municipalities
News The attack on IT systems supplier Miljödata has impacted public sector services across the country
-
A notorious hacker group is ramping up cloud-based ransomware attacks
News The Storm-0501 threat group is refining its tactics, according to Microsoft, shifting away from traditional endpoint-based attacks and toward cloud-based ransomware.
-
Security researchers have just identified what could be the first ‘AI-powered’ ransomware strain – and it uses OpenAI’s gpt-oss-20b model
News Using OpenAI's gpt-oss:20b model, ‘PromptLock’ generates malicious Lua scripts via the Ollama API.
-
Data I/O shuts down systems in wake of ransomware attack
News Regulatory filings by Data I/O suggest the costs of dealing with the attack could be significant
-
Average ransom payment doubles in a single quarter
News Targeted social engineering and data exfiltration have become the biggest tactics as three major ransomware groups dominate
-
BlackSuit ransomware gang taken down in latest law enforcement sting – but members have already formed a new group
News The notorious gang has seen its servers taken down and bitcoin seized, but may have morphed into a new group called Chaos