---

Computer viruses are malicious programs that can self-replicate and cause damage to the data stored on a computer or cripple its performance. Viruses usually spread from computer to computer via internet, network or removable data carriers such as CDs, DVDs and USB flash drives. First created as experiments and pranks, the modern viruses often have more sinister purposes, such as to take control of a computer and use it for specific tasks creating botnets, steal sensitive information like credit card numbers or passwords, or cripple a computer or network. Learn more about the history, nature and threat of computer viruses in this book.

---