perfact::mpa Insecure Direct Object Reference

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Advisory ID: SYSS-2015-069  
Product: perfact::mpa  
Manufacturer: PerFact Innovation GmbH & Co. KG  
Affected Version(s): Custom versions using PerFact DB_Utils (Toolkit) < v3.2  
Tested Version(s): Custom version with PerFact DB_Utils (Toolkit) < v3.2  
Vulnerability Type: Insecure Direct Object References (CWE-932)  
Risk Level: High  
Solution Status: Fixed  
Manufacturer Notification: 2015-12-18  
Solution Date: 2016-01-18  
Public Disclosure: 2016-02-29  
CVE Reference: Not yet assigned  
Authors of Advisory: Matthias Deeg and Sven Freund (SySS GmbH)  
  
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Overview:  
  
The software solution perfact::mpa is a software architecture that, for  
instance, is used to build web applications for the secure and reliable  
remote maintenance of machines via the Internet (see [1]).  
  
According to the manufacturer, remote control software built with  
perfact::mpa impresses through the following features:  
  
* location-independent and central monitoring,  
* maintenance and error management,  
* authorized remote access, and  
* integrated documentation of incidents and services.  
  
Due to improper authorization checks, any logged in user can download  
valid VPN configuration files of arbitrary existing remote sessions.  
  
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Vulnerability Details:  
  
The SySS GmbH found out that any logged in user is able to download  
valid VPN configuration files of arbitrary existing remote sessions.  
  
All an intruder needs to know is the URL with the dynamic parameter   
"brsessid". Due to the modification of this incremental increasing  
integer value, it is possible to enumerate and download a valid  
VPN configuration file for every existing remote session.  
  
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Proof of Concept (PoC):  
  
The following URL is an exemplary request to download a valid VPN  
configuration file for the remote session identified by the ID  
"brsessid":  
  
https://<HOST>/<PATH>/MPA2/RoleSession/Link/connect?brsess_id=<BRSESSID>&brvpnnode_id=1  
  
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Solution:  
  
According to information by the PerFact Innovation GmbH & Co. KG, the  
described security issue has been fixed in PerFact DB_Utils (toolkit)  
software version 3.2.  
  
Please contact the manufacturer for further information or support.  
  
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Disclosure Timeline:  
  
2015-12-18: Vulnerability reported to manufacturer  
2016-01-18: Response from manufacturer with detailed information about  
the reported security vulnerability and its solution status  
2016-02-05: E-mail to manufacturer according two open questions  
2016-02-05: Response from manufacturer with further information  
2016-02-29: Public release of security advisory  
  
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References:  
  
[1] Product Web Site for perfact::mpa  
http://perfact.de/mpa/index_html  
[2] SySS Security Advisory SYSS-2015-069  
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2015-069.txt  
[3] SySS Responsible Disclosure Policy  
https://www.syss.de/en/responsible-disclosure-policy/  
  
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Credits:  
  
This security vulnerability was found by Matthias Deeg and Sven Freund  
of the SySS GmbH.  
  
E-Mail: matthias.deeg (at) syss.de  
Public Key: https://www.syss.de/fileadmin/dokumente/Materialien/PGPKeys/Matthias_Deeg.asc  
Key fingerprint = D1F0 A035 F06C E675 CDB9 0514 D9A4 BF6A 34AD 4DAB  
  
E-Mail: sven.freund (at) syss.de  
Public Key: https://www.syss.de/fileadmin/dokumente/Materialien/PGPKeys/Sven_Freund.asc  
Key fingerprint = DCDB 7627 C1E3 9CE8 62DF 2666 8A5F A853 415D 46DC  
  
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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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