The VBS script files identified by a Trojan.VBS.[variant] detection are distributed as attachments to an email message. At the time of writing, this malware was most frequently reported in Germany, followed by Finland and France.
Delivered via email
For the VBS file analyzed (SHA1: 4eed6655966101b6c7c088d2d54289a77a1f89fe), the email message used to deliver it had the subject line RE:[recipient's username], while the email body is left empty.
Trojan.VBS.URV: Email message
Trojan.VBS.URV: Email file attachments
The VBS file itself was attached to the email as a ZIP file, and used a name with the following format: CONTRACT_[number]_ [username of the recipient].zip. The VBS file itself is named "contract.vbs".
If the user clicks on and opens the attached ZIP file, the VBS file is executed and tries to download an executable file named "contact.exe" from a remote server to the %temp% folder on the user's machine, then run the EXE.
Trojan.VBS.URV: Downloads payload from a remote server
In the sample analyzed, the downloaded EXE file (SHA1:9001ede2a5cdaeb23762cc083f689334599981d2) is ransomware from the Cerber family.
If the EXE file is successfully run, it encrypts files stored on the machine and appends a ".cerber" extension at the end of filename. A payment is then demanded from the user to restore normal access to the affected files.
F-Secure identifies the ransomware separately with the Trojan:W32/Teslacrypt.E!DeepGuard detection.