“Microsoft has released a warning about a new kind of browser-based attack. The attack mimics genuine pages generated by browsers, such as Internet Explorer, Firefox and Chrome, and tricks users into installing a fake anti-virus software. When users visit a compromised website running a malicious code, a genuine looking pop-up surfaces on their web browser, alerting them that their security defences are down and they need to install the an anti-virus software to contain the virus….”
Source: Team Cymru Internet Security News