The SecOps Group Exam CNSP Topic 12 Question 4 Discussion

Port 111/TCP is the default port for the RPC (Remote Procedure Call) portmapper service on Unix systems, which registers and manages RPC services.

Why A is correct: Running rpcinfo -p <hostname> queries the portmapper to list all registered RPC services, their programs, versions, and associated ports. This is a logical next step during a security audit or penetration test to identify potential vulnerabilities (e.g., NFS or NIS services). CNSP recommends this command for RPC enumeration.

Why other options are incorrect:

B . Telnet to the port to look for a banner: Telnet might connect, but RPC services don't typically provide a human-readable banner, making this less effective than rpcinfo.

C . Telnet to the port, send 'GET / HTTP/1.0' and gather information from the response: Port 111 is not an HTTP service, so an HTTP request is irrelevant and will likely fail.

D . None of the above: Incorrect, as A is a valid and recommended step.