You may be familiar with spyware, as it has been in the news a lot in the last year or two, and finally the major software companies are responding with updates to their security software designed to defeat this annoying and potentially very damaging stuff.

While spyware is, to most people, a recent phenomenon in 2005, in fact what could be called spyware (see our definition above) effectively started back in 1996, on what at that time was the most popular ISP, America Online. There was a piece of malicious software designed to grab confidential information of subscribers, the so-called AOL Password Trojans.

Spyware is much more problematic than viruses for several important reasons:

1. The purpose of spyware is to gather information about you – the information may be fairly harmless or confidential, valuable and important
2. Spyware often works silently
3. Spyware is almost never an executable file
4. Spyware is almost entirely undetectable by traditional antivirus software methods, as well as invisible to most firewalls – so it needs to be dealt with on its own, and its presence (at least briefly) on your PC may not entirely avoidable
5. Spyware is everywhere including friendly sites, friendly software and other places, so while there are no good viruses there are some “good” or at least inert pieces of spyware

Spyware hides all over your computer system, and believe it or not, you may actually have agreed indirectly to let it!

You did it by enabling cookies on your Web browser. But disabling cookies may make certain sites not function at all and certain functions within sites unavailable such as most any login, so disabling cookies is usually not the best way to avoid spyware problems. Besides, cookies are often friendly and the spyware ones are easy to separate out with scanning software.

You also did it by downloading items like pictures, video clips and music from websites. But never downloading again isn’t too practical, right?

Most common places for spyware and its various subtypes to “hide” on your machine are:

· Temporary files, especially Temporary Internet Files/Browser Cache
· Cookies (these may be friendly items also)
· Favorites listings
· Registries (these are usually the most seriously bad items)
· In some cases as image files or within image files

A typical small business PC may have upwards of 100,000 files on it, so there are plenty of places for tiny non-executable files to hide.

Spyware comes from many, many places, but the most common kinds of sites are those that are for shopping or offer downloadable information, including:

· Shopping sites and portals
· Bulletin boards and information exchange sites
· Gaming sites
· Download sites
· “Lifestyle” sites such as those aimed at teenagers or brides to be
· Sites that rely on serving customer content
· Adult entertainment sites and portals

It may not be practical to avoid all of these, but a large percentage of spyware does come from these kinds of places.