ZDNet: Printer Friendly - Alarm growing over bot software:
"Known as bot software, the remote attack tools can seek out and place themselves on vulnerable computers, then run silently in the background, letting an attacker send commands to the system while its owner works away, oblivious. The latest versions of the software created by the security underground let attackers control compromised computers through chat servers and peer-to-peer networks, command the software to attack other computers and steal information from infected systems.

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What's new:
Internet security watchers warn that the most common kind of bot software has been upgraded. A new variant incorporates publicly available code for breaching security through a vulnerability on almost every Windows system sold in the past five years.

Bottom line:
Bot software has spread widely--just how quickly is difficult even for security experts to evaluate. Symantec puts the number of computers compromised in the hundreds of thousands. Other security experts have put the number in the millions. Moreover, with source code commonly available, bot software gets quickly updated to take advantage of the latest flaws.…"

http://zdnet.com.com/2100-1105_2-5202236.html?tag=adnews