What is KillDisk? KillDisk is a destructive data wiping malware that has previously been used to sabotage companies by randomly deleting files from the computers.KillDisk is the same component associated with the Black Energy malware that was used to hit several Ukrainian power stations in 2015, cutting power for thousands of people.But according to ESET security researchers, the nasty KillDisk disk wiper malware is back with new variants that target Windows and Linux desktops and servers, encrypt files and then ask for an unusually large ransom: Around $218,000 in Bitcoins – possibly the world's most expensive ransom attacks.What's even worst? Linux variant of the KillDisk ransomware does not store the encryption key anywhere on disk or command-and-control server.So, even after you pay this extremely large ransom, you are not going to get any decryption key for recovery of your important files.