Spyware or adware can be deposited on a computer via an e-mail attachment or as a web site download. It tends to make computers sluggish and less efficient, which is very frustrating for users.
The FTC is thought to have taken the action following a complaint earlier in the year by US rights group the Center for Democracy and Technology, filing suit on Thursday against Seismic Entertainment Productions Inc and SmartBot Net Inc, together with their operator, New Hampshire based Sanford Wallace.
The suit, filed in the US District Court for the District of New Hampshire, alleges that Seismic and SmartBot Net advertise anti-spyware software called Spy Wiper and Spy Deleter by means of pop-up ads that are shown to internet users who visit web sites controlled by the companies.
But the FTC says the defendants have also exploited vulnerabilities in Microsoft's Internet Explorer web browser, that allows them to secretly install software onto users' computers that can change their home page, modify the Internet Explorer search engine, download adware and spyware, and cause pop-up ads to bombard the computer screen.
"Defendants' course of conduct in marketing the Spy Wiper and Spy Deleter software has compelled consumers to either spend $30 to purchase the advertised software, or otherwise spend substantial time and money to resolve these problems with their computers," says the suit.
The FTC has asked the court for an injunction and for the recovery of "ill-gotten gains".
In a statement on one of his web sites, Sandford Wallace confirmed that he and his companies would be cooperating with the investigation. "If in fact it is found that any of our methods are in violation of any current laws, we will immediately cease such activities," he said.
The suit comes shortly after Congress passed two bills aimed at tackling the problem of spyware.
The "Securely Protect Yourself Against Cyber Trespass Act", or SPY ACT, proposes to protect individuals from unknowingly downloading spyware by requiring that consumers be given notice of and consent to the software being downloaded. It also seeks to impose heavy financial penalties for violations of the Act.
The Internet Spyware (I-Spy) Prevention Act on the other hand takes a narrow approach to the issue, aiming to criminalise those who deliberately access a computer without permission.