Microsoft Exchange GsmWriter Deserialization of Untrusted Data NTLM Relay Vulnerability

This vulnerability allows remote attackers to create a denial-of-service condition or relay NTLM credentials on affected installations of Microsoft Exchange. Authentication is required to exploit this vulnerability. The specific flaw exists within the lack of protection against deserialization of the GsmWriter class. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to create a denial-of-service condition on the system or to relay NTLM credentials.