Typically owners of machines that are part of a botnet are completely unaware that their computer has been hijacked. It has been suggested that 95% of all attacks mounted by botnet are from home computers; mainly because most people do not understand how to or why they should secure their PC.

Botnets are most commonly used to send spam and harvest private data from infected machines. However, they are also used to swamp websites with requests to knock them offline – known as a DDoS or Distributed Denial of Service. Additionally, some botnet PCs are used to host phishing sites and other illegal content.

So how can you avoid having your PC being hijacked?
Here’s a simple checklist:

• Never run a program or open a document that arrives via email unless you are sure that it comes from a trusted source. Beware that a program or document sent to you by a friend may well have been obtained from an unreliable source
• Don’t download and run programs or documents from untrusted websites
• Use anti-spyware and anti-virus programs
• On at least a weekly basis update anti-virus and spyware products
• Install a firewall and make sure it is switched on. Most broadband routers contain a firewall. Ensure that it is switched on. Don’t play with your router settings unless you know what you’re doing.
• Password-protect wireless router connections. If they’re not protected, people in neighbouring houses and people in the street with hand-held devices can get into your network.
• Make sure updates to your operating system are installed
• Educate yourself and family about the risks

You might think that it will never happen to you, but it will be a different story when the police or FBI come knocking on your door because your PC has been used to spam millions of email addresses.