A joint report from the Computer Emergency Response Team (Cert), tasked with issuing security warnings, and the U.S. State Department announces an alarming increase of 38% in the number of security flaws identified in 2005 as compared with 2004. A total of 5,198 vulnerabilities were discovered last year and their breakdown according to type of operating system is far from what one would imagine: whereas 812 vulnerabilities affected the Windows environment, 2,328 concerned Unix and Linux and 2,058 were present on several systems at once. It’s clear that no one is safe from software vulnerabilities, regardless of their operating system. Another study, conducted by the Indian consultancy firm Softscan, indicates that authors of viruses have made the most of this increase: more and more malcode is taking advantage of software vulnerabilities and is infecting systems using a simple Internet connection.
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.
