We are seeing the criminals behind fake anti-virus continuing to customize their social engineering attacks to be more believable to users and presumably more successful.
Last week I wrote about fake Firefox malware warnings leading users to rogue security software. This week they've started to imitate Microsoft Update.
The page is nearly an exact replica of the real Microsoft Update page with one major exception... It only comes up when surfing from Firefox on Windows. The real Microsoft Update requires Internet Explorer.
The same site was also hosting the traditional Windows XP explorer scanner we have seen for years, as well as a new Windows 7 scanner.
Similar to spam messages that have corrected their grammar and use correct imagery and CSS, the attackers selling fake anti-virus are getting more professional.
They use high quality graphics and are using information from our UserAgent strings that are sent by the browser to customize your malware experience.
Just like visiting your bank you should only trust security alerts in your browser if you initiated a check with Microsoft, Adobe, Sophos or any other vendor for updates to their software.