A new Internet Explorer exploit in the wild that will allow a malicious website to run malware on your computer. The IE vulnerability stems from an invalid pointer reference that when exploited allows an attacker to execute malicious shell code on underlying machines. The malware caused exploited machines to download further malicious scripts that installed a backdoor.

Microsoft remains committed to taking the appropriate action to help protect our customers. We released Security Advisory 979352 to provide customers with actionable guidance and tools to help with protections against exploit of this vulnerability. Microsoft has not seen widespread customer impact, rather only targeted and limited attacks exploiting IE 6 at this time. Our teams are currently working to develop an update and we will take appropriate action to protect customers when the update has met the quality bar for broad distribution. That may include releasing the update out of band.

It is important to note that complex attacks targeting specific corporate networks are becoming more prevalent in the threat landscape, therefore organizations should follow defense-in-depth best practices, and deploy multiple layers of protection to improve their security posture. In addition, Protected Mode in IE 7 on Windows Vista and later significantly reduces the ability of an attacker to impact data on a user's machine. Customers should also enable Data Execution Prevention (DEP) which helps mitigate online attacks. DEP is enabled by default in IE 8 but must be manually enabled in prior versions.

Customers can also set Internet and Local intranet security zone settings to "High" to prompt before running ActiveX Controls and Active Scripting in these zones or configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. You can find details on implementing these settings in the advisory.