early 2000s

In January 2004, the MyDoom computer worm quickly spread to email inboxes in 168 countries, becoming one of the fastest-spreading pieces of malware in internet history. It exploited human behavior by enticing users to open email attachments that appeared to be delivery errors or system notifications. MyDoom replicated itself through email without corrupting files or destroying data, harvesting email addresses from infected computers to send copies to new victims. The two main variants, MyDoom.A and MyDoom.B, targeted the SCO Group and Microsoft, respectively, and demonstrated the potential for email worms to be weaponized for coordinated attacks. MyDoom primarily targeted Windows-based operating systems and used deceptive emails to propagate. Once infected, it installed a backdoor for unauthorized remote access, forming a botnet for further attacks. MyDoom's effectiveness was due to its alignment with user behavior and the limited security measures of the time, leading to significant disruptions in email communication and an estimated economic impact of approximately billion. Although no longer a current threat, MyDoom's legacy influenced modern email security protocols, leading to improved filtering, behavior-based detection, and multi-layered defense strategies.