Rule:--Sid:3256--Summary:This rule generates an event when an attempt is made to exploit a known vulnerability in Microsoft RPC DCOM.--Impact:Execution of arbitrary code leading to full administrator access of the machine. Denial of Service (DoS).--Detailed Information:A vulnerability exists in Microsoft RPC DCOM such that execution of arbitrary code or a Denial of Service condition can be issued against a host by sending malformed data via RPC.The Distributed Component Object Model (DCOM) handles DCOM requests sentby clients to a server using RPC. A malformed request to an RPC port will result in a buffer overflow condition that will present the attacker with the opportunity to execute arbitrary code with the privileges of the local system account.--Affected Systems:	Windows NT 4.0	Windows NT 4.0 Terminal Server Edition	Windows 2000	Windows XP	Windows Server 2003--Attack Scenarios:An attacker may make a request for a file with an overly long filename via a network share.--Ease of Attack:Simple. Expoit code exists.--False Positives:None known.--False Negatives:None known.--Corrective Action:Apply the appropriate vendor supplied patches.Block access to RPC ports 135, 139 and 445 for both TCP and UDP protocols from external sources using a packet filtering firewall.--Contributors:Sourcefire Research TeamBrian Caswell <bmc@sourcefire.com>Nigel Houghton <nigel.houghton@sourcefire.com>--Additional References:--