Vundo

The Vundo Trojan (commonly known as Vundo, Virtumonde or Virtumondo, and sometimes referred to as MS Juan) is either a Trojan horse or a computer worm that is known to cause popups and advertising for rogue antispyware programs, and sporadically other misbehavior including performance degradation and denial of service with some websites including Google and Facebook. It also is used to deliver other malware to its host computers. Later versions include rootkits and ransomware.