Update 2013May09: Microsoft has issued a ‘Fix-It’ for this problem. This is a temporary, band-aid solution to the problem. It will be superseded by an actual patch at some point. The original bulletin about this issue has been updated to include information about the ‘Fix-It’.

Microsoft recently announced a new attack, targeted at a specific version of Internet Explorer, being exploited in the wild. More details are provided in the associated security advisory from Microsoft.

Only Internet Explorer version 8 is vulnerable to this attack, which begins when someone using IE8 is tricked into visiting a compromised web site. Once infected, the user’s computer can be remotely controlled by the attacker.

Anyone using Internet Explorer 8 is strongly urged to upgrade to IE9, or – if using Windows 7 or 8 – to IE10. If upgrading Internet Explorer is not an option, you can reduce the risk of infection by increasing the level of protection provided by the browser, as follows:

Set Internet and local intranet security zone settings to “High” to block ActiveX Controls and Active Scripting in these zones. This will help prevent exploitation but may affect usability; therefore, trusted sites should be added to the Internet Explorer Trusted Sites zone to minimize disruption.

Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and local intranet security zones. This will help prevent exploitation but can affect usability, so trusted sites should be added to the Internet Explorer Trusted Sites zone to minimize disruption.

Ars Technica has additional details.