"Petya" ransomware encryption cracked

"Petya" ransomware encryption cracked

Utility generates unscrambling key.

Users whose data has been held to ransom by the Petya malware now have an option to decrypt the information, thanks to a new tool that generates an unscrambling key.

Petya appeared around March this year. Once executed with Windows administrator privileges, Petya rewrites the master boot record on the computer's hard drive, crashes the operating system and on restart, scrambles the data on the disk while masquerading as the CHKDSK file consistency utility.

The Petya attackers then demand approximately A$555 in ransom, payable in BItcoin, to provide a decryption key for the locked system.

An anonymous security researcher using the Twitter handle leo_and_stone has now cracked the encryption Petya uses, the Salsa10 function created by DJ Bernstein in 2004.

Decrypting hard disks scrambled with Petya using the tool is a relatively complex operation. The tool requires data from an eight-byte nonce (random, use-once number) file and a 512-byte sector from the hard disk to be input into a website to generate the the decryption key.

This means the Petya-infected hard drive has to be removed from the victim computer, and the small amount of data needed for the decryptor read and copied with low-level system utilities.

Once that is done, the scrambled hard drive has to be reinserted into a computer to bring up the Petya ransom demand screen, at which stage the decryption key can be entered.

Tech support site Bleeping Computer, run by computer forensics specialist Lawrence Abrams, reported success with Leo Stone's Petya decryptor, with keys being generated in just seconds.

A Windows tool to make it easier to extract the verification data and nonce was also created by researcher Fabian Wosar from security vendor Emsisoft.

Recommended

It is difficult for the FBI to crack most smartphone encryption

The FBI is struggling to decode private messages on phones and other mobile devices that could contain key criminal evidence, and the agency failed to access data more than half of the times it tried during the last fiscal year, FBI Director Christopher Wray told House lawmakers. Wray will testify at the House Judiciary Committee ...

Texas Church Shooting: More Calls for Encryption Backdoors

US Deputy Attorney General, Rod Rosenstein, has decided to use the recent mass shooting at a Texas church to reiterate calls for encryption backdoors to help law enforcers. The incident took place at the First Baptist Church in Sutherland Springs, killing at least 26 people. Deceased suspect Devin Kelley’s mobile phone is now in the ...

FBI couldn't retrieve data from nearly 7000 mobile phones due to encryption

The head of the FBI has reignited the debate about technology companies continuing to protect customer privacy despite law enforcement having a search warrant. The FBI says it hasn't been able to retrieve data from nearly 7000 mobile phones in less than one year, as the US agency turns up the heat on the ongoing ...

Wi-Fi's Most Popular Encryption May Have Been Cracked

Your home Wi-Fi might not be as secure as you think. WPA2 -- the de facto standard for Wi-Fi password security worldwide -- may have been compromised, with huge ramifications for almost all of the Wi-Fi networks in our homes and businesses as well as for the networking companies that build them. Details are still ...

暂无评论

发表评论

您的电子邮件地址不会被公开,必填项已用*标注。

This site uses Akismet to reduce spam. Learn how your comment data is processed.