MyDoom variant discovered, spreading

A new variant of MyDoom was discovered on July 26, 2004. Antivirus vendors are split on what to call it. Antivirus vendors Sophos and McAfee refer to the variant as MyDoom.O, while vendors Trend Micro and F-Secure have dubbed it MyDoom.M. The worm contains a backdoor component that some analysts say appears to search out other infected systems.
MyDoom.O/M description