Land rapid7#8298, docs for aux scanner finger

Author: dmohanty-r7

documentation/modules/auxiliary/scanner/finger/finger_users.md

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+## 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](https://nmap.org/nsedoc/scripts/finger.html) script
+
+  ```
+    # nmap -p 79 -sC 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
+  ```