GEN:SID 1:230
Message DDOS shaft client login to handler
Summary This event is generated when a DDoS Shaft client communicates with a Shaft handler.  It is also possible that this event may be generated when any host attempts to discover or detect a Shaft handler.
Impact Attempted DDoS. If the listed source IP is in your network, it may be a Shaft client or a host attempting to discover Shaft handlers.  If the listed destination IP is in your network, it may be a Shaft handler.
Detailed Information The Shaft DDoS uses a tiered structure of compromised hosts to coordinate and participate in a distributed denial of service attack. At the highest level, clients communicate with handlers to direct them to launch attacks.  A client may communicate with a handler via TCP destination port 20432.
Affected Systems Any Shaft compromised host.
Attack Scenarios A Shaft client needs to communicate with handlers to direct attacks.
Ease of Attack Simple. Shaft code is freely available.
Corrective Action Perform proper forensic analysis on the suspected compromised host to discover the means of compromise.

Rebuild a confirmed compromised host.

Use a packet-filtering firewall to block inappropriate traffic to the network to prevent hosts from being compromised.

Additional References Arachnids:
http://www.whitehats.com/info/IDS254
Rule References arachnids: 254
url: security.royans.net/info/posts/bugtraq_ddos3.shtml