finger_users.md

Vulnerable Application

Finger is an older protocol which displays information about users on a machine. This can be abused to verify if a user is valid on that machine. The protocol itself was designed in the 1970s, and is run in cleartext.

The following was done on Kali linux:

1. apt-get install inetutils-inetd fingerd

2. Start the service: /etc/init.d/inetutils-inetd start

Verification Steps

1. Install fingerd

2. Start msfconsole

3. Do: use auxiliary/scanner/finger/finger_users

4. Do: set rhosts

5. Do: run

Options

USERS_FILE

The USERS_FILE is a newline delimited list of users and defaults to unix_users.txt included with metasploit.

Scenarios

A run against the configuration from these docs

  msf > use auxiliary/scanner/finger/finger_users
  msf auxiliary(finger_users) > set rhosts 127.0.0.1
  rhosts => 127.0.0.1
  msf auxiliary(finger_users) > run
  
  [+] 127.0.0.1:79          - 127.0.0.1:79 - Found user: root
  [+] 127.0.0.1:79          - 127.0.0.1:79 Users found: root
  [*] Scanned 1 of 1 hosts (100% complete)
  [*] Auxiliary module execution completed

Confirming using NMAP

Utilizing the finger script

  # nmap -p 79 --script finger 127.0.0.1
  
  Starting Nmap 7.40 ( https://nmap.org ) at 2017-04-26 19:35 EDT
  Nmap scan report for localhost (127.0.0.1)
  Host is up (0.000039s latency).
  PORT   STATE SERVICE
  79/tcp open  finger
  | finger: Login     Name       Tty      Idle  Login Time   Office     Office Phone\x0D
  | root      root       tty2      16d  Apr 10 19:17 (:0)\x0D
  |_root      root      *pts/3      1d  Apr 25 19:11 (192.168.2.175)\x0D
  
  Nmap done: 1 IP address (1 host up) scanned in 0.42 seconds