Firefox users have been flocking to the Netcraft website to download the security company's new anti-phishing toolbar.

The free toolbar, released Tuesday, was downloaded more than 60,000 times within hours of its release, according to Netcraft Internet Services Developer Paul Mutton. By comparison, the company's anti-phishing toolbar for Microsoft's Internet Explorer (IE) browser has been downloaded around 100,000 times since its release earlier this year, he said.

"This seems to indicate that the Firefox community is more interested in security," Mutton said.

An increase in phishing attacks has been grabbing the attention of Internet merchants, end users and security providers alike. Phishing is a type of online fraud in which criminals send e-mails that entice users into visiting Webs sites designed to look like those of a legitimate company, such as a bank or auction provider, for example. Users are asked to enter sensitive information such as a credit card number or passwords.

The scam is currently one of the most prevalent Internet threats, according to security researchers. And given the profit potential, online criminals are becoming more cunning in their attacks, by targeting scams at users of particular banks, or by geographical location, Mutton said.

Netcraft's anti-phishing toolbar seeks to thwart these kinds of threats by blocking access to reported phishing sites. Once the first recipients of a phishing email report the URL of a fake site, the site is blocked for toolbar users.

Netcraft checks each reported site to verify whether it is phony, in order to avoid blocking legitimate sites, Mutton said.

The toolbar also displays the hosting location and a risk rating for each site visited. While the product is free for Internet users, Netcraft licenses a version to organisations such as banks to put their own brand on.

Netcraft has no current plans to offer versions of the toolbar for other browsers.

"There's no other browser as popular as Firefox right now," Mutton said. The open source browser,has nowhere near the market share of IE, but has been steadily gaining users. As of 18 February, IE had a market share in the US of 89.9 percent, down from 92.9 percent in November, according to analytics firm WebSideStory.

Firefox, meanwhile, had grabbed 5.7 percent of the US market as of February, up from 3 percent in November. Internet companies have taken note of its rising popularity. Yahoo began offering a toolbar for Firefox earlier this year, and Google has snapped up one of its key developers. But with success has come a downside: Security researchers are reporting an increase in threats aimed at the alternative browser.

When it comes to phishing, at least, Netcraft hopes to have an answer. "People are showing a lot of interest in the Firefox toolbar," Mutton said.