Breach, Threat Management, Data Security, Malware, Ransomware

MegaCortex ransomware variant threatens data breach, alters credentials

A newly discovered variant of MegaCortex ransomware goes well beyond just encrypting victims' files -- it also changes their Windows passwords and threatens to publish their stolen data if they fail to pay.

In a report earlier this week, BleepingComputer said it helped analyzed the new strain after it was discovered by MalwareHunterTeam and subsequently reverse engineered by researcher Vitali Kremez.

"All of your user credentials have been changed and your files have been encrypted," the ransomware note warns infected victims. Both threats are true: files are encrypted and given an .m3g4c0rtx extension, and victims who attempt to log in to their system will find that they cannot. Instead, all they will see is a legal notice that says "Locked by MegaCortex," along with the attacker-controlled email addresses to contact.

The credential change is made possible by executing the net user command when the ransomware is executed, BleepingComputer reported, citing Kremez.

The ransom note also makes a second threat: "We have also downloaded your data to a secure location. In the unfortunate event of us not coming to an agreement, we will have no choice but to make this data public." It is has been confirmed if the MegaCortex attacks actually have this capability.

The file encryption is reportedly conducted by two extracted DLL files, while a trio of CMD files are leveraged to remove shadow volume copies, wipe free space on the C: drive, create the aforementioned legal notice and clean up the malicious files.

Bradley Barth

As director of multimedia content strategy at CyberRisk Alliance, Bradley Barth develops content for online conferences, webcasts, podcasts video/multimedia projects — often serving as moderator or host. For nearly six years, he wrote and reported for SC Media as deputy editor and, before that, senior reporter. He was previously a program executive with the tech-focused PR firm Voxus. Past journalistic experience includes stints as business editor at Executive Technology, a staff writer at New York Sportscene and a freelance journalist covering travel and entertainment. In his spare time, Bradley also writes screenplays.

Get daily email updates

SC Media's daily must-read of the most current and pressing daily news

By clicking the Subscribe button below, you agree to SC Media Terms and Conditions and Privacy Policy.