GEN:SID 1:209
Message BACKDOOR w00w00 attempt
Summary w00w00 is a Trojan Horse utilizing Telnet. This event is generated when
an attacker attempts to connect to a w00w00 server using Telnet.
Impact Possible theft of data and control of the targeted machine leading to a
compromise of all resources the machine is connected to. This Trojan
also has the ability to delete data, steal passwords and disable the
machine.
Detailed Information This Trojan affects UNIX operating systems:

Due to the nature of this Trojan it is unlikely that the attacker's
client IP address has been spoofed.
Affected Systems  
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 may be due to the exploitation of another vulnerability and
the attacker is leaving another way into the machine for further use.
Ease of Attack This is Trojan activity, the target machine may already be compromised.
Corrective Action Disallow Telnet access from external sources.

Delete the Trojan and kill any associated processes.
Additional References Whitehats arachNIDS
http://www.whitehats.com/info/IDS510
Rule References arachnids: 510