23 - Pentesting Telnet

Basic Information

Telnet is a network protocol that gives users a UNsecure way to access a computer over a network.

Default port: 23

23/tcp open  telnet


nc -vn <IP> 23

All the interesting enumeration can be performed by nmap:

nmap -n -sV -Pn --script "*telnet* and safe" -p 23 <IP>

The script telnet-ntlm-info.nse will obtain NTLM info (Windows versions).

In the TELNET Protocol are various "options" that will be sanctioned and may be used with the "DO, DON'T, WILL, WON'T" structure to allow a user and server to agree to use a more elaborate (or perhaps just different) set of conventions for their TELNET connection. Such options could include changing the character set, the echo mode, etc. (From the telnet RFC) I know it is possible to enumerate this options but I don't know how, so let me know if know how.

Config file


HackTricks Automatic Commands

Protocol_Name: Telnet    #Protocol Abbreviation if there is one.
Port_Number:  23     #Comma separated if there is more than one.
Protocol_Description: Telnet          #Protocol Abbreviation Spelled out

  Name: Notes
  Description: Notes for t=Telnet
  Note: |
    wireshark to hear creds being passed
    tcp.port == 23 and ip.addr != myip


  Name: Banner Grab
  Description: Grab Telnet Banner
  Command: nc -vn {IP} 23

  Name: Nmap with scripts
  Description: Run nmap scripts for telnet
  Command: nmap -n -sV -Pn --script "*telnet*" -p 23 {IP}

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