This indicates an attack attempt against a double-free memory-corruption vulnerability in Microsoft Internet Explorer.
The vulnerability is due to the way the application manages certain HTTP responses. It could lead to a crash in the Internet Explorer or to remote code execution.
Affected Products
Internet Explorer 5.01 Service Pack 4 when installed on Microsoft Windows 2000 Service Pack 4 Internet Explorer 6 Internet Explorer 7
Recommended Actions
Please refer to the following website for the update or patch: http://www.microsoft.com/technet/security/bulletin/MS08-045.mspx