GEN:SID 1:160
Message BACKDOOR NetMetro Incoming Traffic
Summary This event is generated when incoming an data stream associated with the NetMetro Trojan Horse is detected.
Impact Limited control of the target host.
Detailed Information Due to the nature of this Trojan it is unlikely that the attacker's client IP address has been spoofed.

The server portion opens TCP port 5031 by default to establish a connection between client and server. This event indicates that a host external to the protected network running a NetMetro Trojan Server is communicating with a host on the protected network that may be controlling the Trojan.
Affected Systems Windows 95
    Windows 98
    Windows ME
    Windows NT
    Windows 2000
Attack Scenarios This Trojan may be delivered to the target in a number of ways. This event is indicative of an existing infection being activated. Initial compromise can be in the form of a Win32 installation program that may use the extension ".jpg" or ".bmp" when delivered via e-mail for example.
Ease of Attack This is Trojan activity, the target machine may already be compromised. Updated virus definition files are essential in detecting this Trojan.

The Trojan server is named NMS.exe.
Corrective Action A reboot of the infected machine is recommended. The Trojan does not start automatically at boot time nor does it change any system registry settings.
Additional References Whitehats arachNIDS
http://www.whitehats.com/info/IDS79

Dark-e:
http://www.dark-e.com/archive/trojans/NetMetro/index.html
Rule References arachnids: 79