MS07-035 is not categorized as virus, worm, Trojan or backdoor. It is a critical vulnerability in the Win32 API in Windows 2003/XP/2000, which allows to remotely execute arbitrary code in the vulnerable computer.
The Win 32 API (Application Programming Interface) provides applications with 32-bits services, such as a graphical user interface, access system resources, display graphics and formatted text, etc.
If exploited successfully, MS07-035 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 creating a specially crafted web page and enticing users into accessing it. The link to the website can be distributed using several methods, such as email, instant messaging programs, etc.
If you have a Windows 2003/XP/2000 computer, 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 vulnerability replaces a previous one, called MS06-051.