Paul Brislen: It's up to you to avoid spyware defiling your PC

Lately, when I tell people I'm a technology journalist, the first question they ask is "what's all this 'spyware' stuff?"

Spyware, more so than viruses, worms or operating system security flaws, seem to be having a huge impact on end users of all kinds.

Dell Computers reported this week that nearly 20 per cent of all its help desk calls relate to spyware. A University of Washington study claimed 5 per cent of its own machines were running at least four pieces of spyware.

So what is spyware and why has it become such a plague?

Spyware is a catch-all term for nasty little programs that are installed on a user's PC without consent. Spyware can range from cookies, the small pieces of code that identify a user's machine to a website, right through to software that logs every keystroke and sends that potentially sensitive information to a third party in the hope of catching your user names, passwords, account details etc.

Cookies aren't really as bad as many think. They are often used by websites to give the user direct access to subscription-only pages. The New York Times, for example, identifies me every time I go to the page and automatically logs me in. They get to track my movements around the site and gather handy demographics, or they would if I hadn't registered as William Gates esquire, age 7 from Kansas.

Real spyware, however, is far less benign. Hotbar is the classic example of this. Users of Microsoft Internet Explorer or Outlook Express download this small application thinking it's simply going to allow them to personalise their email with tiny animated graphics and other cute touches.

The software also monitors surfing habits and reports back to base so the information can be on-sold to marketing companies. Hotbar slows down connection speeds, particularly for dial-up customers, as the software tries to send its information back to base whenever you connect and also crashes PCs with some operating systems.

But Hotbar is the tip of the iceberg. Some spyware doesn't have any visible presence for the end user. There's no added tab on the browser window, no icon in the system tray. This kind is very difficult to get rid of. They often come with a separate installation file that means the program will reinstall itself even after you've removed it.

Where spyware turns particularly nasty, however, is in the underground world of online porn. British computer publication the Register reported a particularly nasty brand of spyware that not only throws graphic pornographic images on to the screen but also installs bookmarks for porn sites, hijacks the browser's home page and changes it to a very unpleasant porn site and resists any attempts to remove the software. All this from a visit to a page that looked on the surface to be full of games for young children.

How can you tell if you're infected? If your PC or connection starts to run more slowly, if you get a lot of "pop-up" ads or if you find your homepage isn't what it used to be or you find new bookmarks in your "Favourites" folder, you've probably lost control of your PC.

While not foolproof, there are two applications that can be downloaded free and should deal with all but the most unusual spyware installation.

The first is LavaSoft's Ad-Aware. With it the user can scan the hard drive for a known list of spyware applications. The first time this happens on an infected machine can be tedious as the user has to wade through a lengthy list of cookies, applications and files none of which are obviously "good" or "bad".

My decision was to call them all spyware and to quarantine the lot. If I discover I need anything and I've moved it by mistake, it's a relatively easy job to go back and re-authorise that file.

The second application is Spybot Search and Destroy which works in a similar manner to Ad-Aware but looks for a different type of nasty.

One word of warning: Users need both of these applications plus anti-virus software, plus a firewall. They also need to keep operating systems fully updated as well. And, just like anti-virus software, it only works if you keep the signature files updated.

If all that sounds too much like hard work, don't forget that this is predominantly a Microsoft user problem. Switch to a different browser, such Firefox, or a different operating system, such Apple's one, and 99 per cent of these problems disappear.

Microsoft is working on the problem and plans to launch its own anti-spyware application soon and governments are also taking an interest.

Many are considering legislation. Ultimately, it is the user who must beware. A Word of Warning: Don't download the program on offer from Ad Aware as it contains even more spyware than you get rid of.