MS07-031 is not categorized as virus, worm, Trojan or backdoor. It is a critical vulnerability in the Windows Schannel Security Package on Windows 2003/XP/2000 computers, which allows arbitrary code to be remotely executed in the vulnerable computer or Denial of Service attacks to be launched.
The Schannel (Secure Channel) is part of the security package that provides an authentication service to allow secure communications between client and server.
If exploited successfully, on Windows XP computers, MS07-031 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.
On Windows 2003/2000 computers, the vulnerability could cause the affected system to automatically restart.
This vulnerability is usually exploited by hosting a specially crafted website and enticing users into visiting it.
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.