MyDoom

MyDoom, also known as Novarg, is a computer worm that was first discovered on January 26, 2004. It is considered one of the fastest-spreading email worms in history, causing significant disruptions globally. MyDoom spreads by sending itself to email addresses found on an infected computer and creating a backdoor in the victim's operating system. This backdoor can then be used for a variety of malicious activities, such as launching Distributed Denial of Service (DDoS) attacks. The worm caused an estimated $38 billion in damages and remains one of the most infamous computer viruses to date.