GEN:SID 1:1270
Message RPC portmap rstatd request TCP
Summary This event is generated when an attempt is made through a portmap GETPORT request to discover the port where the Remote Procedure Call (RPC) rstatd is listening.

Impact Information disclosure.  This request is used to discover which port rstatd is using.  Attackers can also learn what versions of the rstatd protocol are accepted by rstatd.
Detailed Information The portmapper service registers all RPC services on UNIX hosts. It can be queried to determine the port where RPC services such as rstatd run.  The rstatd RPC service can be queried for performance statistics obtained from the kernel including network, disk, and CPU.  This can provide valuable information to determine which host may make a suitable target to participate in a particular attack.
Affected Systems All hosts running the UNIX portmapper.
Attack Scenarios An attacker can query the portmapper to discover the port where rstatd runs.  This may be a precursor to querying rstatd for usage statistics.
Ease of Attack Easy.  
Corrective Action Limit remote access to RPC services.

Filter RPC ports at the firewall to ensure access is denied to RPC-enabled machines.

Disable unneeded RPC services.
Additional References Arachnids:
http://www.whitehats.com/info/IDS10

Rule References arachnids: 10