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Advisory ID: SYSS-2017-018
Product: OTRS
Manufacturer: OTRS
Affected Version(s): OTRS 5.0.x, OTRS 4.0.x, OTRS 3.3.x
Fixed Version(s): OTRS 5.0.20, OTRS 4.0.24, OTRS 3.3.17
Tested Version(s): 5.0.19
Vulnerability Type: Access to Installation Dialog
Risk Level: High
Solution Status: Fixed
Manufacturer Notification: 2017-05-30
Solution Date: 2017-06-06
Public Disclosure: 2017-06-08
CVE Reference: CVE-2017-9324
Author of Advisory: Sebastian Auwärter, SySS GmbH

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Overview:

OTRS is a ticket management system.

The manufacturer describes the product as follows (see [1]):

"OTRS is one of the most flexible web-based ticketing systems used for 
Customer Service, Help Desk, IT Service Management. With a fast 
implementation and easy customization to your needs it helps you 
reducing costs and increasing the efficiency and transparency of your 
business communication."

Due to insufficient checking of privileges, it is possible to access 
the OTRS Install dialog of an already installed instance, which enables 
an authenticated attacker to change the database settings, superuser 
password, mail server settings, log file location and other parameters.

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Vulnerability Details:

The recommended way to install OTRS is to use the installation dialog 
found at http://vulnerablehost/otrs/installer.pl. After successful 
installation, OTRS prevents further use of this installer. Any 
authenticated user can access the installation functionality of OTRS 
by referencing the installer via a crafted url. The URLs that can be 
used to access the installer can be one of the following:

* http://vulnerablehost/otrs/index.pl?Action=Installer
* http://vulnerablehost/otrs/index.pl?Action=Installer;Subaction=Intro
* http://vulnerablehost/otrs/index.pl?Action=Installer;Subaction=Start
* http://vulnerablehost/otrs/index.pl?Action=Installer;Subaction=System

At the end of each "installation" step, the user is redirected to the 
start page. Therefore, the next step of the installation dialog must be 
called directly using the Intro, Start (Database) or System subaction, 
respectively.

By Using the installer tool, an attacker can change a variety of 
parameters, including the superuser password, database settings, mail 
server settings, log file location and instance ID.

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Proof of Concept (PoC):

On a newly installed instance of OTRS, logged in as any valid user, 
navigate to index.pl?Action=Installer;Subaction=Start to change the 
database parameters or to index.pl?Action=Installer;Subaction=System to 
get a superuser password.

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Solution:

This vulnerability is fixed in the latest versions of OTRS, and it is 
recommended to upgrade to the latest patch level.

Fixed releases can be found at:

https://www.otrs.com/category/release-and-security-notes-en/ 

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Disclosure Timeline:

2017-05-30: Vulnerability discovered
2017-05-30: Vulnerability reported to manufacturer by project member
2017-06-06: Vulnerability reported to manufacturer via security 
            advisory
2017-06-06: Fix provided by manufacturer
2017-06-06: Vulnerability disclosed by manufacturer
2017-06-08: Public release of the security advisory

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References:

[1] Product website for OTRS
    https://www.otrs.com/
[2] SySS Security Advisory SYSS-2017-018
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2017-018.txt
[3] SySS Responsible Disclosure Policy
    https://www.syss.de/en/news/responsible-disclosure-policy/

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Credits:

This security vulnerability was found by Sebastian Auwärter of SySS
GmbH.

E-Mail: sebastian-auwaerter@syss.de
Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Sebastian_Auwaerter.asc
Key Fingerprint: F98C 3E12 6713 19D9 9E2F BE3E E9A3 0D48 E2F0 A8B6

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Disclaimer:

The information provided in this security advisory is provided "as is" 
and without warranty of any kind. Details of this security advisory may
be updated in order to provide as accurate information as possible. The
latest version of this security advisory is available on the SySS Web
site.

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Copyright:

Creative Commons - Attribution (by) - Version 3.0
URL: http://creativecommons.org/licenses/by/3.0/deed.en

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