According to a report by security software firm Symantec, software that tricks users into believing it is protecting them could potentially be installed on tens of millions of machines. Users are encouraged to download such programs with fake security alert pop-ups (something you are likely familiar with) on websites that then go on to offer software to protect against attacks, sometimes free and even sometimes for a fee. Of course, these programs are exactly the kind of thing they claim to defend against, in some cases exposing machines to be taken over for use in botnets. Symantec found a considerable variety of scam software, carrying legitimate sounding names such as Antivirus 2010. It said that around 43 million downloads were attempted in one year, but couldn't be sure how many were successful. It was also surprised to find out how sophisticated some of the tactics used in order to get users to download the software were. For example, scam software makers have been known to operate affiliate models that allow agents convincing people to download the programs to earn money.
While I'm sure most of our members will already be wise to this kind of deception, it reinforces the need to be sure where your software is coming from, and that the source is a reputable one.