Compromised systems can be either the Web servers that host Web sites or your Internet connected PC. Criminals compromise computers by installing viruses, trojan horses and crimeware. These programs can be used to turn your computer into a spamming server or to monitor your online activity to gain access to personal information. A non-properly patch computer or non-firewall computer can be found and attacked within minutes of going online!

More systems are being compromised by automated tools that scan (Mass Scanning) and search for vulnerable systems in which to exploit. Compromised systems can be either the Web servers that host Web sites or broadband connected PCs, which have been compromised, and where a web server has been set up. With automated techniques criminals scan specific network ranges searching for computers that do not have a firewall or are not properly patched. Once the criminals compromise a computer, they install a so called IRC BOT - also called zombie or drone - on it.

Networks of computers "hijacked" by malicious code are called BOTNETS.  BOTNETS can be used as a super computer to attack Web sites or for stealing information and identity theft. In addition, the horsepower of botnets can host phishing Web sites, spam millions of users, distribute malicious code or be used to sell or extort companies with Denial Of Service attacks.