Rule:--Sid:4249--Summary:This event is generated when an attempt is made to exploit a knownvulnerability in Microsoft systems using Microsoft DistributedTransaction Coordinator (MSDTC). In particular this rule generates anevent when an attempt is made to exploit the function "BuildContextW"via the "IXnRemote" component.--Impact:Serious. Execution of arbitrary code leading to unauthorizedadministrative access to the target host.--Detailed Information:Microsoft DTC is used to manage transactions between networked machinesusing the Microsoft Windows operating system.A vulnerability in the implementation of DTC exists due to aprogramming error which may present an attacker with the opportunity toexploit the service and run code of their choosing on an affectedsystem.In particular this rule generates an event when an attempt is made toexploit the function "BuildContextW" via the "IXnRemote" component.--Affected Systems:	Microsoft systems using SMB.--Attack Scenarios:An attacker can supply extra data in the message from the servercontaining code of their choosing to be run on the client.--Ease of Attack:Simple.--False Positives:None known.--False Negatives:None known.--Corrective Action:Apply the appropriate vendor supplied patches.Turn off windows file and print services.Use Samba as an alternative file and print service.--Contributors:Sourcefire Vulnerability Research TeamBrian Caswell <bmc@sourcefire.com>Nigel Houghton <nigel.houghton@sourcefire.com>--Additional References:--