Cybersecurity is constantly evolving, and malicious software (otherwise known as ransomware) is on the rise. Famously placed under the spotlight by the WannaCry ransomware attack that took the globe by storm back in 2017, RegretLocker is a new breed of ransomware that was discovered in October 2020.
Unlike its predecessor, RegretLocker is a new and advanced form of ransomware. It appears simple because it contains a ransom note, and instead of linking to a Tor payment site, it uses email for communication.
What makes RegretLocker different is that it targets the virtual hard drives of virtual machines. It encrypts files by tagging a .mouse extension onto the encrypted files. It also has the ability to mount into virtual hard disks (VHD) using the following sequence, as analyzed by Intel’s Vitali Kremez and discovered by the MalwareHunterTeam:
- In order to mount onto VHD or VHDX files, RegretLocker uses Windows Virtual Storage API to conduct a 3 sequence execution:
- Open Virtual Disk function
- Attach Virtual Disk function
- Get Virtual Disk Physical Path function
- In addition to the above, RegretLocker also utilizes the Windows Restart Manager API, in order to terminate processes or Windows services that keep files open during the encryption process.
- Using the Windows Restart Manager API, the ransomware will not terminate any processes that contain ‘vnc’, ‘ssh’, ‘mstsc’, ‘System’, or ‘svchost.exe’, so as to prevent the termination of critical programs that could be used by the threat actor to access the compromised system.
Currently, RegretLocker is not highly active. However, that doesn’t mean we can take our eyes off the ball. It is vitally important to make sure that the virtual machine infrastructure of your organization is secure.
Contact us at Agilient for professional consultation around systems security and having an effective security management system.
Author: Saeed Baayoun, Agilient Consultant