Spyware, trojans, dialers and viruses can cripple your PC's performance, destroy data and compromise your security. Find out how to identify if your PC is at risk and how to lock it down from attacks in the future by reading this factsheet.

What is spyware?

Spyware is software which can track what you do on a computer and report it back to another computer. With the widespread use of Broadband, spyware has an easy route back to its precipitator. Most spyware is quite benign - almost all applications will 'call home' to check for new versions, including your operating system. There are, however more advanced and aggressive spyware applications which can try to take over your PC, perhaps by forcing your web browser to another search engine page, or by displaying popups. Worse still, some spyware can store every keystroke on your computer, passing this back to its owner - this could include usernames and passwords, along with the websites that you may have entered them into. Still feel safe doing your banking online? Some applications will install a phone dialer which will change your dialup settings - instead of dialing your standard local rate number it'll dial a premium rate number, sometimes several Pounds per minute - you will only find out when you get your bill unless you notice the number's changed, and don't expect the phone company to reimburse you!

Where does spyware come from?

The main spread of spyware comes from the human weakness to get something for nothing. Free toolbars, wallpapers, smileys, application add-ons or 'cracked' software often contain spyware or viruses. So if you download ANYTHING, try to make sure it comes from a reputable source, scan it for viruses and perhaps do a google search to see if anyone else has had problems with this application. Note that some programs require the 'spyware' in order to run, so it's possible that the program will stop working, or work incorrectly after spyware removal, however I have never had this happen to any mainstream program, and this is a warning that most Antispyware apps mention just to cover themselves.

What are viruses?

Viruses have been around for a long time, and have actually become less destructive (at least in my opinion). Going back 15 years it was not uncommon for a virus to wipe out the boot sector of the hard disc, similar to ripping out the index of a book. Nowadays viruses can corrupt files but most concentrate on their own propagation and stealth. They'll try to bypass or even disable your antivirus software and firewall, send themselves out to all of your address book and perhaps deliver another payload - some even turn your PC into a 'zombie' to perform predefined tasks. This might either be a SPAM attack or a DoS (Denial of Service) attack, where any infected PC sends out junk data to one specific server. If enough PCs do this it effectively swamps the server so that it cannot respond to legitimate traffic, bringing it down. Make sure all of your anti virus software is updated to keep out of harms way.