
Firefox in 117 instances failed to flag a phishing site when IE7 did catch it. The Microsoft browser let 243 URLs slip through that Firefox would stop.
Paid for by Mozilla, the study was performed by Smartware, a technology, strategy and marketing firm. The test methodology and results were audited by security testing provider iSEC Partners.
The test fed a series of known phishing URLs from PhishTank to the browsers over a period of two weeks late October and early November.
The study follows a September study by Microsoft which gave top marks to Internet Explorer 7. The study didn't test Firefox 2 but compared the browser to a series of seven third party security applications.
The Microsoft study was performed by 3Sharp, a company specialising in messaging architectures that has no track record in market research and security analysis.
A study's results are available on the Mozilla Developer Centre website.