From 2-spyware.com
Vgkf ransomware is a cryptovirus that belongs to a malware family known as Djvu ransomware. The version is coming after more than 360 variants on the list. This malware encrypts all the important files on a Windows computer, appends them with .vgkf extension, and restricts access to them.
Once encryption[1] is done and these files get locked, the ransom message gets dropped in those folders with encoded files and on the desktop. In the ransom note _readme.txt, cybercriminals behind the attack explain that the only way to recover data is by paying ransom in Bitcoin. The sum can vary, depending on how soon victims contact the developers because the discount of 50% is offered within the first 72 hours since the locking.