Botnets: What are They?

A botnet (also known as a zombie army) is a number of Internet computers that, although their owners are unaware of it, have been set up to forward transmissions (including spam or viruses) to other computers on the Internet.
Any such computer is referred to as a zombie - in effect, a computer "robot" or "bot" that serves the wishes of some master spam or virus originator. Most computers compromised in this way are home-based.
According to a report from antivirus labs, botnets - not spam, viruses, or worms - currently pose the biggest threat to the Internet. An average of 57,000 active bots was observed per day over the six months of 2006.
An attacker usually gains control by infecting the computers with a virus or other malicious code that gives the attacker access. Your computer may be part of a botnet even though it appears to be operating normally. Botnets are often used to conduct a range of activities, from distributing spam and viruses to conducting denial-of-service attacks.
The main problem with botnets is that they are hidden and may stay undetected unless you are specifically looking for certain activity.

What can you do to protect yourself?

• Use and maintain anti-virus software - Anti-virus software recognizes and protects your computer against most known viruses, so you may be able to detect and remove the virus before it can do any damage.
• Install a firewall - Firewalls may be able to prevent some types of infection by blocking malicious traffic before it can enter your computer and limiting the traffic you send.
• Use good passwords - Select passwords that will be difficult for attackers to guess, and use different passwords for different programs and devices.
• Keep software up-to-date - Install software patches so that attackers can't take advantage of known problems or vulnerabilities.
• Follow good security practices - Take appropriate precautions when using email and web browsers to reduce the risk that your actions will trigger an infection.