|
If you use internet, there is over 90% chance your computer is infected with spyware - Source CNN |
Effects and behaviorsWindows-based computers can rapidly accumulate a great many spyware components. The consequences of a moderate to severe spyware infection (privacy issues aside) generally include a substantial loss of system performance (over 50% for bad infections), and major stability issues (crashes and hangs). Another common symptom involves difficulty in connecting to the Internet.Spyware infection occasions more visits to professional computer repairers than any other single cause. In many cases, the user has no awareness of spyware and assumes that the system performance, stability, and/or connectivity issues relate to hardware, to Windows installation problems, or to a virus. To have spyware professionally removed typically costs about $50 US. Owners of badly infected systems not infrequently buy an entire new computer system because the existing system "has become too slow".
Some spyware products have additional consequences. Stealth dialers may attempt to connect directly to a particular telephone number rather than to a user's own intended ISP: where connecting to the number in question involves long-distance or overseas charges, this can result in massive telephone bills which the user has no choice but to pay. A few spyware vendors, notably 180 Solutions, have written what the New York Times has dubbed "stealware" — spyware applications that redirect affiliate links to major online merchants such as eBay and Dell, effectively hijacking the commissions that the affiliates would have expected to earn in the process. Some other types of spyware (Targetsoft, for example) modify system files to make themselves harder to remove. (Targetsoft modifies the Winsock (Windows Sockets) files. The deletion of the spyware-infected file "inetadpt.dll" will interrupt normal networking usage.) Spyware, along with other threats, has led some former Windows users to move to other platforms such as Linux or Apple Macintosh. Spyware and cookiesAnti-spyware programs often report web advertisers' HTTP cookies as spyware. Cookies in themselves do not constitute application software, but simply consist of variables set by web sites (including advertisers). But cookies can serve to help track web-browsing activity, for instance to maintain a "shopping cart" for an online store or to maintain consistent user settings on a search engine.Only the web-site that sets cookies can accessed them. In the case of cookies associated with advertisements, the ostensible advertiser generally does not controlling the cookies: they come under the puview of a third-party site referenced by a banner ad image. Some web-browsers and privacy tools offer to reject cookies from sites other than the one that the user requested. Advertisers use cookies to track people's browsing among various sites carrying ads from the same firm -- and thus to build up a marketing profile of the person or family using the computer. For this reason many users object to such cookies, and for the same reason anti-spyware programs offer to remove them. Typical examples of spywareA few examples of common spyware programs may serve to illustrate the diversity of behaviors found in these attacks.CoolWebSearch, a group of programs, installs through the exploitation of Internet Explorer vulnerabilities. The programs direct traffic to advertisements on Web sites including coolwebsearch.com. To this end, they display pop-up ads, rewrite search engine results, and alter the infected computer's hosts file to direct DNS lookups to these sites. Internet Optimizer, also known as DyFuCa, redirects Internet Explorer error pages to advertising. When users follow a broken link or enter an erroneous URL, they see a page of advertisements. However, because passworded Web sites (HTTP Basic authentication) use the same mechanism as HTTP errors, Internet Optimizer makes it impossible for the user to access passworded sites. 180 Solutions transmits extensive information to advertisers about the web sites which users visit. It also alters HTTP requests for affiliate advertisements linked from a Web site, so that the advertisements make unearned profit for the 180 Solutions company. It opens pop-up ads that cover over the Web sites of competing companies. |
Only rarely does a single piece of software render a computer unusable. Rather, a computer rarely has only one infection. As the 2004 AOL study noted, if a computer has any spyware at all, it typically has dozens of different pieces installed. The cumulative effect, and the interactions between spyware components, typically cause the stereotypical symptoms reported by users -- a computer which slows to a crawl, overwhelmed by the many parasitic processes running on it. Moreover, some types of spyware disable software firewalls and anti-virus software, and reduce browser security settings, opening the system to further opportunistic infections, much like an immune deficiency disease.