The government is warning parents and educators about a new threat on the internet: web sites that nearly duplicate legitimate ones, but whisk children and others into an electronic maze of pornography.

The Federal Trade Commission called the ploy “page-jacking,” describing it recently as the most pernicious example it has discovered in the 100 cases of internet deception it has investigated.

The agency showed how a consumer who tried to visit an internet site about a popular movie, Saving Private Ryan, was sent with no warning to web sites with lurid photographs advertising “barely legal Asian girls.”

When puzzled surfers try to close those browser windows, other windows that open automatically display different pornographic sites.

In extreme cases, those sites also temporarily can disable a web browser’s “back” and “forward” navigation buttons to make it even more difficult to leave them.

“Think about what it would be like if you saw your 7-year-old child looking at this, and she couldn’t turn if off and you couldn’t turn it off,” said Jodie Bernstein, director of the commission’s Bureau of Consumer Protection.

The FTC, alleging deception and unfair trade, said it obtained temporary restraining orders in U.S. District Court against Carlos Pereira, believed to be living in Portugal, and Guiseppe Nirta of Australia and his company, WTFRC Ltd.

Allen Asher, deputy chairman of the Australian Competition and Consumer Commission, confirmed that federal police there served search warrants.

The FTC said that some types of internet filtering software are effective in blocking these pornographic sites, especially software that analyzes text or images from a web page before displaying it.

Here’s how the scheme works:

• A company’s popular web site is digitally copied, including the hidden “meta tags” that help the internet’s search engines categorize its content, and published on different computers.

• A few lines of software code, called Javascript, are hidden within the duplicated web site to immediately redirect visitors elsewhere—often to pornographic sites that pay a few cents for online referrals—and to make it difficult for a person to shut down the browser software or surf elsewhere.

Bernstein recommended that parents and educators consider disabling Java script technology in their web browsers, a procedure that can require about a half-dozen mouse-clicks. But that also prevents legitimate sites from using the technology.

One victim compared page-jacking to opening a family restaurant, then finding an adult bookstore built across the street in an identical building and under the restaurant’s own marquee.

“It’s like some sleazeball has tunneled under your front door and set up a trap door,” said John G. Fischer of Irving, Texas, a lawyer for Adrenaline Vault, a web site that fell victim this spring. Youngsters looking there for details about software games instead found their computer screens filled with pornography.

The FTC said it helped uncover evidence of the scheme using its new internet lab, a suite with eight modern computers and four investigators whose job is to click and protect.

Don Blumenthal, who runs the lab, said the FTC uses a private internet provider as its investigators surf the web to avoid tipping companies that the government, with its familiar “” moniker, is visiting. The agency also is establishing secret eMail accounts for these digital detectives to cloak their online identities.

The FTC has taken a lead role among federal agencies enforcing U.S. laws on the internet, but its unclear how its lawyers and eight new computers will make more than a tiny dent in the fraud on the web, where criminals can organize operations overseas to thwart U.S. laws and can vanish and reappear under different names in a matter of hours.

Federal Trade Commission

Bureau of Consumer Protection