A Mozilla-commissioned study has given the anti-fraud features in the Firefox 2 browser high marks, finding they are much more effective than those in Internet Explorer 7.

The study, commissioned by Firefox maker Mozilla and carried out by SmartWare, comes on the heels of a Microsoft-commissioned study that found just the opposite - concluding that IE 7 led the pack.

The SmartWare study, released on Tuesday, used 1,040 phishing sites as verified by the PhishTank community-powered anti-phishing service. It found that Firefox 2's blacklist feature blocked about 79 percent of the sites, while IE 7's whitelist-based Auto Check OFF blocked 16 of the sites, less than 2 percent.

The study also compared Firefox 2's Ask Google feature, which checks sites against a Google-provided list of phishing sites, with IE 7's Auto Check ON, finding that the Firefox feature blocked 848 of the sites compared with 690 for IE 7.

SmartWare noted that there were large gaps in which sites were blocked, with 243 cases where Firefox blocked a site but IE didn't, and 117 cases where IE blocked a site that was given the all-clear by Firefox.

The browsers were tested over a period of two weeks using a custom web application tied into PhishTank's XML feed of scam URLs.

Last month's Microsoft-funded study measured things quite differently, generating an "accuracy" score based on detection rates as well as other factors such as false positives and the effectiveness of the action taken when a site is flagged.

In that study, IE 7 ended up with a score of 172, only four ahead Netcraft’s toolbar which scored 168. Firefox was a distant third with 106, eBay fourth on 92, Earthlink ScamBlocker fifth on 76, GeoTrust Trustwatch sixth with 67, Netscape 8.1 seventh with 56, and McAfee SiteAdvisor coming in last place with an almost useless 3.