MegaCortex is described by security researchers as a new, highly targeted ransomware variant that contains numerous references to the '90s cult film The Matrix.
The ransomware was first discovered at the beginning of 2019 but of the 76 reported attacks, 47 took place last week across the US, Italy, Canada, France, the Netherlands, and Ireland.
Targeted organizations reported the attacks coming from a compromised domain controller (DC), which may have been accessed by using stolen admin credentials. The attacker executes commands through the compromised DC that's the hacker is remotely accessing using the reverse shell.
"The DC uses WMI to send out the malware - a copy of PsExec renamed rstwg.exe, the main malware executable, and a batch file — to the rest of the computers on the network that it can reach, and then runs the batch file remotely via PsExec," explains Sophos.
The batch file contains a list of commands to terminate 44 processes and 189 services and disable 194 services, preventing any security tools from stopping the ransomware in its tracks. The batch file then launches winnit.exe to drop and execute the DLL payload.
What's different about this ransomware is that there is no ransom fee. Instead, the organization is met with a ransomware note offering a "consultation on how to improve your companies cybersecurity" and a promise that doing so will "guarantee" they won't attack again.
To help mitigate the risk of infection, NNT recommends at a minimum keeping any machines using RDP behind a VPN, enabling multi-factor authentication (CIS Control 16), and replacing all admin passwords. We also recommend leveraging our custom Ransomware Mitigation Kits to automatically fix any security weaknesses.
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