The most common way in which the Skull Ransomware is being delivered to victims is through the use of spam email attachments. The victims will receive a spam email message with an attached file. When the file is opened, downloads and installs Skull on the victim's computer.
Skull encrypts the victims' files and then demands the payment of a ransom in exchange for decrypting the victim's files. Skull delivers its ransom note in an HTML file named 'How_To_Decrypt_Your_Files.html,' dropped on the infected computer's desktop. The ransom note delivered simply says:
All your files have been encrypted! If you read this file, that's mean all your files was encrypted by the Skull Ransomware.