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Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.


Threat LevelLow threatDamageHighDistributionNot widespread


MS10-049 is not categorized as virus, worm, Trojan or backdoor. It is a group of critical vulnerabilities in the SChannel on Windows 2008/7/Vista/2003/XP, which allows arbitrary code to be remotely executed and spoofing.

The SChannel is part of the security package that helps provide an authentication service to provide secure communications between client and server.

The addressed vulnerabilities are:

  • TLS/SSL Renegotiation vulnerability: it is a spoofing vulnerability that exists in the TLS/SSL protocol implemented in the Windows SChannel authentication component.

    If exploited successfully, it could allow an attacking user to introduce information on a TLS/SSL protected connection.

    This vulnerability is usually exploited by setting up a man-in-the-middle attack between a client and server, interrupting their connection as soon as an SSL renegotiation attempt takes place.
  • SChannel Malformed Certificate Request Remote Code Execution vulnerability: this remote code execution vulnerability exists because SChannel does not sufficiently validate certificate request messages sent by the server.

    If exploited successfully, MS10-049 allows hackers to gain remote control of the affected computer with the same privileges as the logged on user.

    This vulnerability is usually exploited by hosting a specially crafted website and convincing users to access it. The link to the malicious website can be distributed using different means, like email or instant messaging programs.


If you have a 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.