A problem with the Microsoft SmartScreen malware-thwarting technology in Internet Explorer 8 rendered countless users unable to access all kinds of sites throughout the day on November 4.
Microsoft officials seem to have licked the problem by the end of the work day on the East Coast, but had posted no explanation as to its cause.
There are numerous tweets from frustrated IE users attempting to access banks, financial sites and other Web properties, noting that those sites were being reported as malicious by IE 8 even though they were not.
SmartScreen Filter is a feature introduced in Internet Explorer 8 designed to help users avoid "socially engineered malware phishing websites and online fraud." The filter checks sites against a "dynamically updated list" of reporting phishing/malware sites, and checks software downloads against reported sites. If a user tries to visit a site that is marked as malicious, a screen pops up advising that user not to continue to the unsafe site.
Update: Microsoft is providing the following statement but no further details as to which sites were affected or what caused the problem. From a spokesperson:
"The SmartScreen Filter was unintentionally blocking a group of websites sites earlier today. The issue has been resolved and we apologize to the customers and sites that were affected. We understand the root cause and have taken preventive action. We take security seriously and are committed to delivering a trusted browsing experience."