"YOU are surfing the net, and stop at a sports site you regularly visit to read the latest headlines. You are always careful to avoid sites that appear suspect, so you feel safe online. Unbeknownst to you, though, and to the innocent owner of the website, a piece of malicious code has been added to the page you are viewing. This uploads software onto your computer via your browser, turning it into a "zombie" PC under the remote control of a malicious user.
While installing firewalls and antivirus software on your computer may keep it safe from conventional threats such as worms and viruses, these security tools do not inspect data downloaded through browsers - a loophole that attackers can exploit. "The firewall is dead," says Google security specialist Niels Provos.
As a result of this loophole, PCs are increasingly becoming infected with "bot" software, creating networks of zombie computers, or botnets."
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