In Pictures: 20 notorious worms, viruses and botnets

The earliest worms and viruses were created for geeky fun and did little harm - oh, how times have changed. Here are 20 worms, viruses and botnets that show the evolution of malware, from Creeper to Flame.

Conficker

The massive number of machines infected by Conficker got everyone's attention, says Haley. The real interesting thing about it, though, and what caused even more fear was the great unknown: What would happen when the resulting botnet woke up on a date specified in the threat's code.

Fortunately, it did not live up to people's worst expectations.

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