Advisory ID: SYSS-2019-021
Product: Cynap
Manufacturer: WolfVision
Affected Version(s): 1.18g, 1.28j
Tested Version(s): 1.18g, 1.28j
Vulnerability Type: Use of Hard-coded Cryptographic Key (CWE-321)
Risk Level: High
Solution Status: Fixed
Manufacturer Notification: 2019-05-03
Solution Date: 2019-06-19
Public Disclosure: 2019-07-04
CVE Reference: CVE-2019-13352
Authors of Advisory: Manuel Stotz, Gerhard Klostermeier (SySS GmbH)

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Overview:

WolfVision Cynap is a wireless collaboration and presentation system.

The manufacturer describes the product as follows [1]:

"Cynap is a stand-alone all-in-one wireless collaboration and
presentation system which includes a built-in media player, web
conferencing, on-board recording and streaming , BYOD screen sharing
for all mobile devices, and annotation functionality, making it the
ideal device to form the centrepiece of new and adapted classrooms and
meeting spaces."

Due to the use of a hard-coded cryptographic key, an attacker can
generate support PINs for resetting the administrative user password in
order to gain administrative access to the device.

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Vulnerability Details:

SySS GmbH found out that the WolfVision Cynap wireless collaboration
and presentation system uses a static, hard-coded cryptographic secret
for generating support PINs used for the provided 'forgot password'
functionality.

By knowing this static secret and the corresponding algorithm for
calculating support PINs, an attacker can reset the password of the
administrative user account "ADMIN" and thus gain unauthorized access to
the affected Cynap device via a network connection.

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Proof of Concept (PoC):

SySS GmbH developed a software tool for generating support PINs either
in online or offline mode.

The following output of the software tools illustrates a successful
attack resulting in a reset password for the administrative user
account "ADMIN".

$ python ./wolfvision_cynap_keygen.py --online 192.168.40.109
WolfVision vSolution Cynap Keygen
               by
          Manuel Stotz
      Gerhard Klostermeier

[*] Launch keygen in online mode ... [OK]
[*] Gathering data ... [OK]
    [*] Serialnumber: <SERIAL NUMBER>
    [*] Support PIN: 447301
[*] Generating new Support PIN ... [OK]
    [+] New Support PIN: 723247
        [*] Account: ADMIN
        [*] Password: Password
[*] Bye!

A successful attack against a vulnerable WolfVision Cynap device gaining
administrative access is demonstrated in our SySS PoC video
"Administrating WolfVision Cynap the Hacker's Way" [5].

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Solution:

Install the firmware version 1.30j provided by the manufacturer
WolfVision [2].

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Disclosure Timeline:

2019-05-03: Vulnerability reported to manufacturer
2019-05-10: Vulnerability reported to manufacturer again
2019-05-13: Manufacturer confirms receipt of security advisory
2019-05-31: Manufacturer schedules firmware update 1.30j with fix for
            the reported security issue
2019-06-19: Release of firmware update 1.30j including security fix
2019-07-04: Public release of SySS security advisory
2019-07-08: Release of updated security advisory with assigned CVE ID

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References:

[1] Product website for WolfVision Cynap

https://www.wolfvision.com/vsolution/index.php/en/presentation-systems/cynap/cynap
[2] WolfVision firmware downloads
    https://wolfvision.com/vsolution/index.php/de/support/downloads
[3] SySS Security Advisory SYSS-2019-021

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2019-021.txt
[4] SySS Responsible Disclosure Policy
    https://www.syss.de/en/responsible-disclosure-policy/
[5] SySS Proof-of-Concept Video "Administrating WolfVision Cynap the
Hacker's Way"
    https://youtu.be/veEtiYAWvMY

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Credits:

This security vulnerability was found by Manuel Stotz and Gerhard
Klostermeier of SySS GmbH.

E-Mail: manuel.stotz (at) syss.de
Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Manuel_Stotz.asc
Key fingerprint = F051 5B74 7E70 193E 7F66 0133 E790 F68A BCE6 8C6D

E-Mail: gerhard.klostermeier (at) syss.de
Public Key:
https://www.syss.de/fileadmin/dokumente/PGPKeys/Gerhard_Klostermeier.asc
Key fingerprint = 8A9E 75CC D510 4FF6 8DB5 CC30 3802 3AAB 573E B2E7

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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