The Finger is a simple but very widely used tool for enumeration made use of by hackers and security testers alike. It enables one to check for who is logged in to a Unix system with the help of one single solitary lonely command. The tool is both a server and a client. The tool’s daemon (fingered) works with TCP port number 79.
It can expose info for the attacker to exploit and abuse such as the login names, login times, root, etc. People who have some experience working with UNIX may have come across the use of the Finger for the purpose of determining who was running some process that looked like it had taken over the Operating System (OS).
This could be by creating some endless loop or causing another process or more to freeze up. Prior to stopping the process, the administrator may want to find out about the owner of the process and to be in contact with him or her so as to get to know what is running and subsequently stop the problem from coming back.
Nessus can also be used for Unix system enumeration purposes. For instance, when scanning a system with the Red Hat Linux 5 Enterprise, the tool shows that an mDNS daemon listening in exposes info like the hostname of the system as well as the list of its running services.
Nessus will give info like which Linux process is listening in on the port in question, the Nessus ID, the Synopsis of the whole enumeration process, the description of the service in question, the solution to the problem, the risk factor (such as the level of risk that is involved in this vulnerability ends up compromising the system), the plugin output such as the computer name, the ethernet address, the computer type, and the OS it is running. As can be seen from this info, a lot of can be utilized.