Telnet Service Banner Detection - Metasploit


This page contains detailed information about how to use the auxiliary/scanner/telnet/telnet_version metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Table Of Contents
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Module Overview

Name: Telnet Service Banner Detection
Module: auxiliary/scanner/telnet/telnet_version
Source code: modules/auxiliary/scanner/telnet/telnet_version.rb
Disclosure date: -
Last modification time: 2020-06-11 13:09:25 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: telnet
Target network port(s): 23
List of CVEs: -

Detect telnet services

Module Ranking and Traits

Module Ranking:

  • normal: The exploit is otherwise reliable, but depends on a specific version and can't (or doesn't) reliably autodetect. More information about ranking can be found here.

Basic Usage

This module is a scanner module, and is capable of testing against multiple hosts.

msf > use auxiliary/scanner/telnet/telnet_version
msf auxiliary(telnet_version) > show options
    ... show and set options ...
msf auxiliary(telnet_version) > set RHOSTS ip-range
msf auxiliary(telnet_version) > exploit

Other examples of setting the RHOSTS option:

Example 1:

msf auxiliary(telnet_version) > set RHOSTS 192.168.1.3-192.168.1.200

Example 2:

msf auxiliary(telnet_version) > set RHOSTS 192.168.1.1/24

Example 3:

msf auxiliary(telnet_version) > set RHOSTS file:/tmp/ip_list.txt

Required Options

  • RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'

Knowledge Base

Description

This module will scan a range of machines and prints the banner, usually containing the version of any telnet servers that are running on it.

Verification Steps

  1. Do: use auxiliary/scanner/telnet/telnet_version
  2. Do: set RHOSTS [IP]
  3. Do: set THREADS [number of threads]
  4. Do: run

Scenarios

msf > use auxiliary/scanner/telnet/telnet_version 
msf auxiliary(scanner/telnet/telnet_version) > set RHOSTS 1.1.1.0/24
RHOSTS => 1.1.1.0/24
msf auxiliary(scanner/telnet/telnet_version) > set THREADS 254
THREADS => 254
msf auxiliary(scanner/telnet/telnet_version) > run

[*] 1.1.1.2:23 TELNET (GSM7224) \x0aUser:
[*] 1.1.1.56:23 TELNET Ubuntu 8.04\x0ametasploitable login:
[*] 1.1.1.116:23 TELNET Welcome to GoodTech Systems Telnet Server for Windows NT/2000/XP (Evaluation Copy)\x0a\x0a(C) Copyright 1996-2002 GoodTech Systems, Inc.\x0a\x0a\x0aLogin username:
[*] Scanned 254 of 256 hosts (099% complete)
[*] Scanned 255 of 256 hosts (099% complete)
[*] Scanned 256 of 256 hosts (100% complete)
[*] Auxiliary module execution completed
msf auxiliary(scanner/telnet/telnet_version) >

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Msfconsole Usage

Here is how the scanner/telnet/telnet_version auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/telnet/telnet_version

msf6 auxiliary(scanner/telnet/telnet_version) > show info

       Name: Telnet Service Banner Detection
     Module: auxiliary/scanner/telnet/telnet_version
    License: Metasploit Framework License (BSD)
       Rank: Normal

Provided by:
  hdm <[email protected]>

Check supported:
  No

Basic options:
  Name      Current Setting  Required  Description
  ----      ---------------  --------  -----------
  PASSWORD                   no        The password for the specified username
  RHOSTS                     yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT     23               yes       The target port (TCP)
  THREADS   1                yes       The number of concurrent threads (max one per host)
  TIMEOUT   30               yes       Timeout for the Telnet probe
  USERNAME                   no        The username to authenticate as

Description:
  Detect telnet services

Module Options

This is a complete list of options available in the scanner/telnet/telnet_version auxiliary module:

msf6 auxiliary(scanner/telnet/telnet_version) > show options

Module options (auxiliary/scanner/telnet/telnet_version):

   Name      Current Setting  Required  Description
   ----      ---------------  --------  -----------
   PASSWORD                   no        The password for the specified username
   RHOSTS                     yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT     23               yes       The target port (TCP)
   THREADS   1                yes       The number of concurrent threads (max one per host)
   TIMEOUT   30               yes       Timeout for the Telnet probe
   USERNAME                   no        The username to authenticate as

Advanced Options

Here is a complete list of advanced options supported by the scanner/telnet/telnet_version auxiliary module:

msf6 auxiliary(scanner/telnet/telnet_version) > show advanced

Module advanced options (auxiliary/scanner/telnet/telnet_version):

   Name                 Current Setting  Required  Description
   ----                 ---------------  --------  -----------
   CHOST                                 no        The local client address
   CPORT                                 no        The local client port
   ConnectTimeout       10               yes       Maximum number of seconds to establish a TCP connection
   Proxies                               no        A proxy chain of format type:host:port[,type:host:port][...]
   SSL                  false            no        Negotiate SSL/TLS for outgoing connections
   SSLCipher                             no        String for SSL cipher - "DHE-RSA-AES256-SHA" or "ADH"
   SSLVerifyMode        PEER             no        SSL verification method (Accepted: CLIENT_ONCE, FAIL_IF_NO_PEER_CERT, NONE, PEER)
   SSLVersion           Auto             yes       Specify the version of SSL/TLS to be used (Auto, TLS and SSL23 are auto-negotiate) (Accepted: Auto, TLS, SSL23, SSL3, TLS1, TLS1.1, TLS1.2)
   ShowProgress         true             yes       Display progress messages during a scan
   ShowProgressPercent  10               yes       The interval in percent that progress should be shown
   TelnetBannerTimeout  25               yes       The number of seconds to wait for the initial banner
   TelnetTimeout        10               yes       The number of seconds to wait for a reply from a Telnet command
   VERBOSE              false            no        Enable detailed status messages
   WORKSPACE                             no        Specify the workspace for this module

Auxiliary Actions

This is a list of all auxiliary actions that the scanner/telnet/telnet_version module can do:

msf6 auxiliary(scanner/telnet/telnet_version) > show actions

Auxiliary actions:

   Name  Description
   ----  -----------

Evasion Options

Here is the full list of possible evasion options supported by the scanner/telnet/telnet_version auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(scanner/telnet/telnet_version) > show evasion

Module evasion options:

   Name                Current Setting  Required  Description
   ----                ---------------  --------  -----------
   TCP::max_send_size  0                no        Maxiumum tcp segment size.  (0 = disable)
   TCP::send_delay     0                no        Delays inserted before every send.  (0 = disable)

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Error Messages

This module may fail with the following error messages:

Error Messages

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

A network issue has occurred: <E.MESSAGE>

Here is a relevant code snippet related to the "A network issue has occurred: <E.MESSAGE>" error message:

35:	        banner_santized = Rex::Text.to_hex_ascii(banner.to_s)
36:	        print_good("#{ip}:#{rport} TELNET #{banner_santized}")
37:	        report_service(:host => rhost, :port => rport, :name => "telnet", :info => banner_santized)
38:	      end
39:	    rescue ::Rex::ConnectionError, ::Errno::ECONNRESET => e
40:	      print_error("A network issue has occurred: #{e.message}")
41:	      elog("A network issue has occurred", error: e)
42:	    rescue Timeout::Error => e
43:	      print_error("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.")
44:	      elog("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.", error: e)
45:	    rescue ::Exception => e

A network issue has occurred

Here is a relevant code snippet related to the "A network issue has occurred" error message:

36:	        print_good("#{ip}:#{rport} TELNET #{banner_santized}")
37:	        report_service(:host => rhost, :port => rport, :name => "telnet", :info => banner_santized)
38:	      end
39:	    rescue ::Rex::ConnectionError, ::Errno::ECONNRESET => e
40:	      print_error("A network issue has occurred: #{e.message}")
41:	      elog("A network issue has occurred", error: e)
42:	    rescue Timeout::Error => e
43:	      print_error("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.")
44:	      elog("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.", error: e)
45:	    rescue ::Exception => e
46:	      print_error("#{e} #{e.backtrace}")

<TARGET_HOST>:<RPORT>, Server timed out after <TO> seconds. Skipping.

Here is a relevant code snippet related to the "<TARGET_HOST>:<RPORT>, Server timed out after <TO> seconds. Skipping." error message:

38:	      end
39:	    rescue ::Rex::ConnectionError, ::Errno::ECONNRESET => e
40:	      print_error("A network issue has occurred: #{e.message}")
41:	      elog("A network issue has occurred", error: e)
42:	    rescue Timeout::Error => e
43:	      print_error("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.")
44:	      elog("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.", error: e)
45:	    rescue ::Exception => e
46:	      print_error("#{e} #{e.backtrace}")
47:	      elog(e)
48:	    end

<TARGET_HOST>:<RPORT>, Server timed out after <TO> seconds. Skipping.

Here is a relevant code snippet related to the "<TARGET_HOST>:<RPORT>, Server timed out after <TO> seconds. Skipping." error message:

39:	    rescue ::Rex::ConnectionError, ::Errno::ECONNRESET => e
40:	      print_error("A network issue has occurred: #{e.message}")
41:	      elog("A network issue has occurred", error: e)
42:	    rescue Timeout::Error => e
43:	      print_error("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.")
44:	      elog("#{target_host}:#{rport}, Server timed out after #{to} seconds. Skipping.", error: e)
45:	    rescue ::Exception => e
46:	      print_error("#{e} #{e.backtrace}")
47:	      elog(e)
48:	    end
49:	  end

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See Also

Check also the following modules related to this module:

Authors

hdm

Version

This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.

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