Rule:Backdoor.BackOrifice--Sid:112, 116--Summary:Backdoor.BackOrifice is a Trojan Horse.Server Port: 31337 although in later versions this port can be changedto a value between 1 and 65535Protocol: UDP although in later versions TCP can also be used--Impact:Possible theft of data and control of the targeted machine leading to acompromise of all resources the machine is connected to. This Trojanalso has the ability to delete data, steal passwords and disable themachine.--Detailed Information:This Trojan affects the following operating systems:	Windows 95	Windows 98	Windows ME	Windows NTThe Trojan changes system registry settings to add the BackOrifice severto programs normally started on boot. Due to the nature of this Trojanit is unlikely that the attacker's client IP address has been spoofed.The default name of the server application is UMGR32, which can bechanged on first use. The new application may be installed in the systemor system32 direcory and the original may also be deleted.Event messages relating to activity from this Trojan are:	SID	Message	---	-------	112	BackOrifice access (outgoing TCP connection)	116	BackOrifice access (incoming UDP connection)--Attack Scenarios:This Trojan may be delivered to the target in a number of ways. Thisevent is indicative of an existing infection being activated. Initialcompromise can be in the form of a Win32 installation program that mayuse the extension ".jpg" or ".bmp" when delivered via e-mail forexample.--Ease of Attack:This is Trojan activity, the target machine may already be compromised.Updated virus definition files are essential in detecting this Trojan.--False Positives:None Known--False Negatives:None Known--Corrective Action:Edit the system registry to remove the extra keys or restore apreviously known good copy of the registry.Affected registry keys are:	HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ServicesHKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServicesRegistry keys added may vary, look for spurious entries in the abovelocations.BackOrifice may hide the process from viewing inthe Windows taskmanager. A reboot of the infected machine is recommended.--Contributors:Original Rule Writer Max Vision <vision@whitehats.com>Sourcefire Research TeamBrian Caswell <bmc@sourcefire.com>Nigel Houghton <nigel.houghton@sourcefire.com>--Additional References:Whitehats arachNIDShttp://www.whitehats.com/info/IDS399Symantec Security Responsehttp://www.symantec.com/avcenter/venc/data/back.orifice2000.trojan.html--