MS10-051 is not categorized as virus, worm, Trojan or backdoor. It is a critical vulnerability in XML Core Services, which allows arbitrary code to be remotely executed in the vulnerable computer. The affected version is XML Core Services 3.0.
The vulnerability is due to the way in which XML Core Services handles HTTP responses.
If exploited successfully, MS10-051 allows hackers to gain remote control of the affected computer with the same privileges as the logged on user. If this user had administrator rights, the hacker could take complete control of the system: create, modify or delete files, install programs, create new user accounts, etc.
This vulnerability is usually exploited by hosting a specially crafted website designed to invoke XML through Internet Explorer, and enticing users to access it. The link to the malicious website can be distributed via email or instant messaging programs.
If you have XML Core Services 3.0 on Windows 2008/7/Vista/2003/XP, it is recommended to download and apply the security patch for this vulnerability. Click here to access the web page for downloading the patch.
Bear in mind that this security bulletin replaces a previous one, called MS08-069.