Files with dll suffix may be also encountered as files encrypted and renamed by the FSociety ransomware.
DLL file extension - FSociety ransomware affected file
What is dll file? How to open dll files?
File type specification:
File extension dll seems to be also related to a ransomware encountered first in November 2016. Much like other nefarious ransomware, it encrypts users files and changes the original suffix and demands a ransom from the user for the decryption keys.