According to the Redmond, Wash., developer, IE7 users may see their PCs bog down as the filter evaluates multiframe pages for fraud indicators. On pages with a large number of frames, or when the user browses several frames in a short time, IE7's processor appetite spikes.
"When you use Windows Internet Explorer 7 to visit a Web page, the computer may respond very slowly as the Phishing Filter evaluates Web page contents," Microsoft said in a support document it posted Tuesday.
IE 7's anti-phishing filter was touted by Microsoft as one of several security enhancements to the new browser. The filter checks each site against a list of known or likely fraudulent pages kept on a Microsoft-run server. Mozilla Corp.'s Firefox 2.0, on the other hand, checks visited sites against a list of potentially dangerous sites kept on the PC. Microsoft and Mozilla have made conflicting claims that their anti-phishing tool is the best in the business.
The patch, which was not automatically pushed to IE7 users running Windows XP SP2 or Windows Server 2003, or posted on the list of possible fixes on Microsoft Update, can be downloaded from the Microsoft site. Users must be running a legitimate copy of Windows to grab the patch.