Microsoft recently posted Security Advisory (927892) for a critical vulnerability in Microsoft XML Core Services. This vulnerability was discovered in the field and allows for remote code execution. This equates to another means for drive-by attacks via Internet Explorer. Exploitation is not believed to be wide spread at this time, but we can expect exploit code to become public early in the week at which point exploitation will pick up exponentially.

Workarounds include setting the kill bit for the XMLHTTP 4.0 ActiveX Control and modifying Internet Explorer’s security settings. For more information, see:
http://www.microsoft.com/technet/security/advisory/927892.mspx

McAfee Avert Labs is currently analyzing this threat.