Unfortunately, we have already seen ransomware auto-propagate in the form of the Virlock file infector, now we have the Wana Crypt0r 2.0 worm fully automated. The significance of this is that the victim is entirely passive in the infection. Simply being unpatched could lead to an infection causing the victim’s files to become encrypted. The Wana Crypt0r ransomware worm was created by mating the Equation Group’s ETERNALBLUE exploit for MS17-010 with the previous generation of the ransomware. Wana Crypt0r ransomware is also known as Wana Decrypt0r 2.0, WannaCry, WCry, and WanaCrypt. Upon infection, it makes recovery more difficult by deleting the Volume Shadow copies and backups.
Because ransomware like Wana Crypt0r 2.0 is able to delete Volume Shadow copies, Netskope advises users to backup important files in the cloud and to turn on versioning. This will create a recoverable backup solution that is difficult for ransomware authors to defeat. Netskope also detects copies of the Wana Crypt0r 2.0 executable as Backdoor.WannaCryptr.A, Backdoor.Wannacryptr.B, Backdoor.Wannacryptr.C or Backdoor.Wannacryptr.D.
Upon execution, encrypted files will be renamed to use extensions such as .wncry, .wnry, .wcry and .wncrypt. The following ransom note will be displayed, which provides a test mechanism to decrypt some files for free.
Figure 1: Ransom note from WannaCryptr
Netskope recommends the following best practices to enterprises in order to protect from ransomware threats: