MydoomIsolated Date: 2004Estimated cost: $38 billionMydoom was created by an anonymous programmer, Mydoom was a nasty little virus that mostly affected Windows XP. Mydoom is a Worm that infects Windows operating systems and was used extensively in a variety of attacks, such as the hacks on Sony Pictures in 2014. The first infected email was sent in late 2006. It was famously known for infecting in the compromise of hundreds of millions of email addresses and hundreds of millions of users. Mydoom infected 25% of whole emails in 2004. Mydoom used to have a ransom function that was to be paid in the form of gift certificates or some sort of digital currency in order to gain access to infected computers. Mydoom is another virus that was created to trick users into getting infected with malware. It caused so much damage to computers and people that it has become one of the most infamous viruses ever.