Unix Command Shell, Bind TCP (via BusyBox telnetd) - Metasploit


This page contains detailed information about how to use the payload/cmd/unix/bind_busybox_telnetd metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

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Module Overview

Name: Unix Command Shell, Bind TCP (via BusyBox telnetd)
Module: payload/cmd/unix/bind_busybox_telnetd
Source code: modules/payloads/singles/cmd/unix/bind_busybox_telnetd.rb
Disclosure date: -
Last modification time: 2021-01-05 14:59:46 +0000
Supported architecture(s): cmd
Supported platform(s): Unix
Target service / protocol: -
Target network port(s): -
List of CVEs: -

Listen for a connection and spawn a command shell via BusyBox telnetd

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

msf > use payload/cmd/unix/bind_busybox_telnetd
msf payload(bind_busybox_telnetd) > show options
    ... show and set options ...
msf payload(bind_busybox_telnetd) > generate

To learn how to generate payload/cmd/unix/bind_busybox_telnetd with msfvenom, please read this.

Knowledge Base

The cmd/unix/bind_busybox_telnetd payload provides a bind TCP Unix command shell via BusyBox telnetd.

Vulnerable Application

cmd/unix/bind_busybox_telnetd should work on either 32 or 64-bit Linux platforms with BusyBox telnetd installed.

Options

LOGIN_CMD

The command telnetd will execute on connect. The default value is /bin/sh in order to provide a command shell.

Advanced

CommandShellCleanupCommand

The command to run before the session is closed. The default value is pkill telnetd and is used to avoid leaving a persistent command shell that does not require authentication.

Deploying cmd/unix/bind_busybox_telnetd

To set the payload:

  1. In msfconsole, load the exploit.
  2. Do: set PAYLOAD cmd/unix/bind_busybox_telnetd
  3. Do: exploit

Notes

The shell cleanup command should result in the payload automatically terminating the telnetd service as the session completes. However, intermittent behavior was observed and the source has not been identified. When closing a session please verify, via a port scan or other desired method, that the port is no longer open. If the port remains open, then the unauthenticated telnetd service is still running. Establish a connection to the unauthenticated telnetd service and manually terminate the process (pkill telnetd) to avoid leaving the host more insecure.

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Msfconsole Usage

Here is how the cmd/unix/bind_busybox_telnetd payload looks in the msfconsole:

msf6 > use payload/cmd/unix/bind_busybox_telnetd

msf6 payload(cmd/unix/bind_busybox_telnetd) > show info

       Name: Unix Command Shell, Bind TCP (via BusyBox telnetd)
     Module: payload/cmd/unix/bind_busybox_telnetd
   Platform: Unix
       Arch: cmd
Needs Admin: No
 Total size: 26
       Rank: Normal

Provided by:
  Matthew Kienow <matthew_kienow[AT]rapid7.com>

Basic options:
Name       Current Setting  Required  Description
----       ---------------  --------  -----------
LOGIN_CMD  /bin/sh          yes       Command telnetd will execute on connect
LPORT      4444             yes       The listen port
RHOST                       no        The target address

Description:
  Listen for a connection and spawn a command shell via BusyBox 
  telnetd

Module Options

This is a complete list of options available in the cmd/unix/bind_busybox_telnetd payload:

msf6 payload(cmd/unix/bind_busybox_telnetd) > show options

Module options (payload/cmd/unix/bind_busybox_telnetd):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   LOGIN_CMD  /bin/sh          yes       Command telnetd will execute on connect
   LPORT      4444             yes       The listen port
   RHOST                       no        The target address

Advanced Options

Here is a complete list of advanced options supported by the cmd/unix/bind_busybox_telnetd payload:

msf6 payload(cmd/unix/bind_busybox_telnetd) > show advanced

Module advanced options (payload/cmd/unix/bind_busybox_telnetd):

   Name                        Current Setting  Required  Description
   ----                        ---------------  --------  -----------
   AutoRunScript                                no        A script to run automatically on session creation.
   AutoVerifySession           true             yes       Automatically verify and drop invalid sessions
   CommandShellCleanupCommand  pkill telnetd    yes       A command to run before the session is closed
   CreateSession               true             no        Create a new session for every successful login
   InitialAutoRunScript                         no        An initial script to run on session creation (before AutoRunScript)
   VERBOSE                     false            no        Enable detailed status messages
   WORKSPACE                                    no        Specify the workspace for this module

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See Also

Check also the following modules related to this module:

Authors

Matthew Kienow <matthew_kienow[AT]rapid7.com>

Version

This page has been produced using Metasploit Framework version 6.1.36-dev. For more modules, visit the Metasploit Module Library.

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