A cryptocurrency-themed email urging you to take note of a payment that has “timed out” and needs to be resent has been doing rounds in the recent weeks, spotted researchers. These emails have been using two types of malicious files to distribute Mortal Kombat ransomware and Laplas Clipper malware.
According to researchers, targets may either receive a demand for payment to unlock encrypted files or have their cryptocurrency details stolen from the system clipboard.
The attacks have been ongoing since December 2022 and have affected individuals, small and large organisations, with no specific target. The infection chain starts with an email containing a malicious attachment.
MortalKombat Ransomware and Laplas Clipper: Two threats working together
Researchers at Cisco Talos has been monitoring an unidentified actor since December 2022 who is using MortalKombat ransomware and a Laplas Clipper malware GO variant to steal cryptocurrency from victims.
The attacker is targeting victims with an exposed remote desktop protocol port and is using one of their download servers to run an RDP crawler and distribute the MortalKombat ransomware.
Victims include small and large organisations, as well as individuals. The attacker distributes malicious attachments in emails to initiate the infection chain, which may result in a demand for payment to unlock encrypted files or the theft of cryptocurrency details from the system clipboard.
The infection chainbegins with a cryptocurrency themed email harbouring a malicious attachment, which lures with the claim that a payment of has “timed out” and will need resending.
“The email comes with a dubious zip attachment containing a BAT loader that begins the infection process when it’s executed. The BAT loader kicks off a chain of events that results in the download and execution of the ransomware or the clipper malware, from one of two URLs,” said a threat assessment report by MalwareByte Labs.
According to Talos, the MortalKombat ransomware belongs to the Xorist family, based on similarities in code, class name, and registry key strings.
MortalKombat Ransomware: Mode of operation
The MortalKombat ransomware is designed to encrypt a wide range of files on the victim’s computer, including system, application, database, backup, virtual machine files, and files on remote locations mapped as logical drives.
In addition to encrypting these files, the ransomware drops a ransom note and changes the victim’s wallpaper to display instructions on negotiating with cybercriminals.
The note advises the victim to use a Tor-based instant messaging app called qTOX and pay the ransom in Bitcoin. If the victim has difficulty registering a new account on qTOX, the attacker provides a ProtonMail email address.
Unlike some ransomware strains, MortalKombat does not feature a wiper function. However, it corrupts system folders, such as the Recycle Bin, to prevent the victim from retrieving files. It also disables the Windows Run command window and removes all entries from Windows startup.
To ensure persistence, the ransomware creates a Run registry key called “Alcmeter” and deletes the root registry key of the installed application in the HKEY_CLASSES_ROOT registry hive. By deleting these entries, the applications can no longer function.
The cybercriminals behind MortalKombat ransomware also use a cryptocurrency hijacker called Laplas, which monitors the Windows clipboard for crypto addresses and substitutes them for addresses under the attacker’s control.
It is unclear whether MortalKombat is a custom strain of a lone threat actor or sold to other cybercriminals like Laplas. However, MortalKombat is a financially motivated campaign that targets individuals and businesses in multiple countries.
To protect against ransomware and other cyber threats, it is crucial to remain vigilant against suspicious emails, links, or downloads and implement robust security measures. By doing so, you can reduce the risk of falling victim to cybercriminals and suffering the devastating consequences of a ransomware attack.