Introduced into our computers without our knowledge, they slow down operations, display unwanted adverts or spy on our surfing habits: given their increasing presence, spyware (spy software) have lately become almost as much of a threat as viruses. They come in many guises and are sometimes teamed up with Trojan horses or techniques for identity theft. According to a recent study, 15% of spy software try to steal passwords or spy on keystrokes to access confidential information. This may only be a small percentage compared to other categories of spyware (20% of spy software "settle" for drawing up a technical profile of the infected machine and 60% have a commercial purpose) but it is nevertheless a significant amount and should spur you to protect your computer.
They are perhaps the most irritating of spyware, but not necessarily the most dangerous: adware are spy software that display unwanted adverts when you connect to the Internet. They not only impede web navigation but also make it considerably slower while adverts aimed at adults can sometimes contain shocking content. Adware can infiltrate computers either when you install free software that contains adware (as with some music file-sharing software) or when you visit booby-trapped web pages. In theory, their aim is to show adverts, preferably targeted to the interests of the Internet user. When they aren't paired with a Trojan horse - which also happens - the nuisance they cause is mainly limited to displaying unwanted adverts.
They may not necessarily contain viruses or Trojan horses, but spyware that change your web browser’s homepage really do behave like a malicious code. By exploiting software flaws, they can infiltrate a computer when a user simply visits a web page. Particularly difficult to eradicate, this new family of spyware/adware modifies the computer’s registry to change the web browser’s homepage, making it impossible to reset the homepage using standard methods. Some of this spyware also make it impossible to navigate on certain web sites. The best known of this type of spyware is CoolWebSearch, which directs users towards the site of the same name, but some versions also contain Trojan horses. All of which means that users must be extra-vigilant and not forget to update their software.
In contrast to easily-detected adware - it's hard to miss the tidal wave of ad windows appearing on your screen - "informer" spyware act very discreetly, usually without the Internet user even being unaware of it. These "informers" often have commercial objectives and collect information on the users' behavior (web pages visited, words used in search engines, etc.), but they still represent just as much of a threat. They are a risk to privacy and can sometimes collect information which is very useful to hackers, such as domain name, programs installed, security software used, the computer's IP address, the operating system version or even the status of security updates.
Some spyware make even more of a nuisance of themselves and install in the user's PC Trojan horses which then try to steal confidential information (passwords, bank card details…) or even serve as relay posts for other attacks. These are the most dangerous spyware as they also infiltrate your computer by exploiting security flaws found in the most common software.
Although the development of high-speed Internet connections has rendered these kinds of spyware almost obsolete, they are still a threat to those who connect via a modem and a standard telephone line. Known as ’dialers’, they dial high-cost phone numbers without your knowledge while you’re surfing the net - at great cost to your phone bill!
