In terms of functionality Cerber is not very different than other ransomware threats. It encrypts files with the strong AES-256 algorithm and targets dozens of file types, including documents, pictures, audio files, videos, archives and backups.
The program encrypts file contents and file names and changes the original extensions to .cerber. It can also scan for and encrypt available network shares even if they are not mapped to a drive letter in the computer.
Once the encryption process is done, Cerber will drop three files on the victim's desktop named "# DECRYPT MY FILES #." They contain the ransom demand and instructions on how to pay it. One of those files is in TXT format, one is HTML and the third contains a VBS (Visual Basic Scripting).
The VBS file is unusual. According to Lawrence Abrams, administrator of the technical support forum BleepingComputer.com, the file contains text-to-speech code that converts text into an audio message.
"When the above script is executed, your computer will speak a message stating that your computer's files were encrypted and will repeat itself numerous times," Abrams said in a blog post.
According to Cyber intelligence outfit SenseCy, Cerber's creators are selling the ransomware as a service on a private Russian-language forum. This makes it available to low-level criminals who might not have the coding skills or resources to create their own ransomware. It also means that this threat might see widespread distribution.