Bitdefender releases free MortalKombat ransomware decryptor tool

Bitdefender has released a free decryption tool for the MortalKombat ransomware strain which has risen to prominence in recent months.

First observed by Cisco Talos researchers in January, the strain has been used to target a raft of victims in the UK, US, and further afield to steal cryptocurrency.

In a blog post on 28 February, Bitdefender said the decryption tool can be “run silently” through a command line. The company added that this could enable automated deployment in large networks if needed.

The decryptor does not require installation on infected systems and scans a device filesystem to identify specific files infected by the ransomware strain. Users are also able to create backups of encrypted files as a contingency.

This marks the latest in a series of decryptor tools rolled out by Bitdefender in recent years. The company previously released decryptors for REvil and GandCrab ransomware strains.

How does MortalKombat work?

Based on the Xorist ransomware strain, MortalKombat is typically spread through phishing emails and targets exposed remote desktop protocol (RDP) instances, Bitdefender said.

A recent study from Cisco found that the initial infection vector for MortalKombat often takes the form of a phishing email in which attackers impersonate CoinPayments, a cryptocurrency payment gateway and wallet.

Emails targeting users often contain a spoofed sender email, luring in unsuspecting victims.

“A malicious ZIP file is attacked with a filename resembling a transaction ID mentioned in the email body, enticing the recipient to unzip the malicious attachment and view the contents, which is a malicious BAT loader,” researchers explained.

Once embedded within an infected machine, the ransomware strain targets user crypto wallets and tracks user activity to identify wallet addresses.

If successful in identifying a crypto wallet address, this is transferred to the attacker’s server and swapped with a malicious address to compromise future transactions. Affected users are met with a ransom note and their device wallpaper is changed to an image from the Mortal Kombat game series.

Little is known about the ransomware’s developers and operating model, according to researchers. However, the ransomware was first observed in a financially-motivated campaign of attacks which harnessed a new version of the Laplas Clipper malware written in Go.

“The name of the ransomware and the wallpaper it drops on the victim system are almost certainly a reference to the MortalKombat media franchise, which encompasses a series of popular video games and films,” a Cisco Talos blog post read.