Average Lifespan of Bot-Infected Computers

During the first six months of 2007, the lifespan of the average bot-infected computer was four days. This is an increase from the previous period, when the average lifespan was three days. The median lifespan of a bot-infected computer during both periods was one day. This indicates that the majority of bot-infected computers only participate in attacking behavior for a short period, after which they are either identified and disinfected, or are used for activities other than carrying out Internet attacks, such as hosting spam zombies or phishing Web sites.

Source: Symantec Internet Security Threat Report, Vol. XII