Message-ID: <4b93505c-4ed5-05b4-4590-2b50969f32a5@sec-consult.com>
Date: Tue, 31 May 2022 10:13:02 +0000
From: "SEC Consult Vulnerability Lab,
 Research via Fulldisclosure" <fulldisclosure@...lists.org>
To: "fulldisclosure@...lists.org" <fulldisclosure@...lists.org>
Subject: [FD] SEC Consult SA-20220531-0 :: Backdoor account in Korenix
 JetPort 5601V3

SEC Consult Vulnerability Lab Security Advisory < 20220531-0 >
=======================================================================
               title: Backdoor account
             product: Korenix JetPort 5601V3
  vulnerable version: Firmware version 1.0
       fixed version: None
          CVE number: CVE-2020-12501
              impact: High
            homepage: https://www.korenix.com/
               found: 2020-04-06
                  by: T. Weber (Office Vienna)
                      SEC Consult Vulnerability Lab

                      An integrated part of SEC Consult, an Atos company
                      Europe | Asia | North America

                      https://www.sec-consult.com

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

Vendor description:
-------------------
"Korenix Technology, a Beijer group company within the Industrial Communication
business area, is a global leading manufacturer providing innovative, market-
oriented, value-focused Industrial Wired and Wireless Networking Solutions.
With decades of experiences in the industry, we have developed various product
lines [...].

Our products are mainly applied in SMART industries: Surveillance, Machine-to-
Machine, Automation, Remote Monitoring, and Transportation. Worldwide customer
base covers different Sales channels, including end-customers, OEMs, system
integrators, and brand label partners. [...]"

Source: https://www.korenix.com/en/about/index.aspx?kind=3


Business recommendation:
------------------------
The vendor stated that they "will not remove the hardcoded backdoor
account as it is needed for customer support and it can't be cracked in a reasonable
amount of time."


SEC Consult recommends not to use those devices in production environments and
to perform a thorough security review conducted by security professionals to
identify and resolve potential further critical security issues.


Vulnerability overview/description:
-----------------------------------
1) Backdoor Accounts (CVE-2020-12501)
Multiple different backdoor accounts were found during quick security checks
of different firmware files. One backdoor account was tested on a later bought
device to verify this specific finding. A telnet service is running on the
device by default. This increases the risk of exploitation on the local network.


Proof of concept:
-----------------
1) Backdoor Accounts (CVE-2020-12501)
The following account is available on at least one JetPort device of Korenix.
There might be more affected devices across this vendor. Westermo and Comtrol
devices may be affected too.

  * User "superrd", present on:
  - JetPort 5601V3
    More devices may be affected.

Two other users are present on the system according to "/etc/passwd". An
additional telnet-daemon is listening on port 19999.

root:<no password>
superrd:<not cracked>
admin:admin


By inspecting "/etc/passwd", the only user that is allowed to login
to the device is "superrd":

root::0:0:root:/root:/bin/false
superrd:$1$<redacted>:0:0::/root:/bin/sh
admin:$1$$CoERg7ynjYLsj2j4glJ34.:502:502::/:/bin/true


The listener has been identified by using "ps" and "netcat":
# ps
   PID  Uid     VmSize Stat Command
     1 root       1452 S   init [3]
[...]
   253 root       1780 S   /usr/bin/ser2net -p 600 -c /tmp/com2ip.conf
   254 root        288 S   /usr/sbin/telnetd -p 19999
   289 root        788 S   /usr/bin/dropbear
   297 root       1916 S   /usr/bin/thttpd -C /etc/thttpd.conf -cert /etc/thttpd

# netstat -tulen
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
[...]
tcp        0      0 0.0.0.0:19999           0.0.0.0:*               LISTEN
[...]

The vulnerability has been manually verified on an emulated device
by using the MEDUSA scalable firmware runtime.


Vulnerable / tested versions:
-----------------------------
The following product / firmware version has been tested:
* Korenix JetPort 5601V3     / 1.0


Vendor contact timeline:
------------------------
2020-04-14: Contacting CERT@VDE through info@...t.vde.com and requested support
             for the disclosure process due to the involvement of multiple
             vendors.
2020-04-15: Security contact responded, that the products were developed by
             Korenix Technologies.
2020-04-30: Security contact informed us, that some vulnerabilities were
             confirmed by the vendor.
2020-07-30: Call with Pepperl+Fuchs contact. Contact stated that the
             vulnerabilities were reported to Korenix.
2020-09-29: Call with Pepperl+Fuchs and CERT@VDE regarding status.
             Pepperl+Fuchs stated that they just have a sales contact from
             Korenix.
2020-10-05: Coordinated release of SA-20201005-0.
2020-10-05: Call with the helpdesk of Beijer Electronics AB. The contact stated
             that no case regarding vulnerabilities were opened and created one.
             The product owners of Westermo, Korenix and Beijer Electronics were
             informed via this inquiry. Set disclosure date to 2020-11-25.
2020-10-06: Restarted the whole responsible disclosure process by sending a
             request to the new security contact cs@...jerelectronics.com.
2020-10-07: Received an email from a Korenix representative which offered to
             answer questions about product security. Started responsible
             disclosure by requesting email certificate or whether plaintext can be
             used. Referred to the request to cs@...jerelectronics.com.
             No answer.
2020-11-11: Asked the representatives of Korenix and Beijer regarding the
             status.
             No answer.
2020-11-25: Phone call with security manager of Beijer. Sent advisories via
             encrypted archive to cs@...jerelectronics.com. Received
             confirmation of advisory receipt. Security manager told us that he
             can provide information regarding the timeline for the patches
             within the next two weeks.
2020-12-09: Asked for an update.
2020-12-18: Call with security manager of Beijer. Vendor presented initial
             analysis done by the affected companies.
2021-03-21: Security manager invited SEC Consult to have a status meeting.
2021-03-26: Agreed on an advisory split as other affected products will get
             patched later.
2021-04-12: Performed advisory split.
2021-05-26: Meeting regarding advisory publication. Agreed to release this
             advisory in Q4.
2021-06-01: Released related advisory SA-20210601-0.

2021-06-24: Beijer Electronics contact informs us that he leaves the company
             today. Refers us to new contact in CC.

2021-07-05: Follow-up meeting with new vendor contact regarding next steps.
2021-07-16: Contact from Beijer Electronics reached out to Korenix. Engineers
             from Korenix are still investigating the issues. JetWave 2311 went
             EoL, next status update in August 2021. JetPort will be fixed in
             Q1 2022.
2021-09-15: Asked for status update;
2021-09-20: Korenix will provide a time schedule for the patches by end of next
             week.
2021-09-28: Meeting regarding the schedule. Fixes will be available by end of
             the year for Korenix JetWave series.
2021-09-28: Update call with vendor; Fixes will be available in November.
2021-11-18: Contact had difficulties to get a response from Korenix. JetWave
             2212G 1.8.0 has been released, other fixes will be released in
             December.
2021-11-22: Vendor provides all other fixed versions, which have already been
             put online.
2021-12-17: Performed another advisory split.
2021-12-20: Update call with vendor. Identified another possibly affected
             device (JetWave 3420). Investigation will be started from Korenix
             as soon as possible.
2021-12-28: Vendor has rolled out an update for the JetWave 3420 V3 firmware.
2022-01-17: Informed vendor about the advisory release within the next two
             weeks.
2022-01-19: Call with vendor; agreed that advisory can be published for
             JetWave series.
2022-01-24: Informed vendor about advisory release on 2022-01-31.
2022-01-31: Released related advisory SA-20220131-0.
2022-02-22: Vendor says, that fixes are estimated to be completed by end of
             February.
2022-03-29: Most issues from the related advisories (SA-20201005-0, SA-20210601-0)
             are not applicable according to the vendor, only the backdoor account
             exists in the JetPort series. The JetPort series will not go end of life.

             The backdoor is needed in order to assist customers with problems and
             Korenix claims the password can't be cracked in a reasonable amount of time,
             hence it will not be fixed.

             Security contact states that there is no point in waiting and we can
             release the security advisory.

2022-04-05: Another call to clarify with security contact; Korenix will not remove
             the account as this issue is not considered as critical.
2022-05-18: Tried to re-send the advisory for final review which only contains the
             backdoor account information. Received auto-reply that our contact from
             Beijer Group (who did the coordination with Korenix) was no longer part
             of the company.
2022-05-31: Public release of security advisory.


Solution:
---------
None available. The vendor stated that they "will not remove the hardcoded backdoor
account as it is needed for customer support and it can't be cracked in a reasonable
amount of time."


Workaround:
-----------
None


Advisory URL:
-------------
https://sec-consult.com/vulnerability-lab/


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

SEC Consult Vulnerability Lab

SEC Consult, an Atos company
Europe | Asia | North America

About SEC Consult Vulnerability Lab
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult, an
Atos company. 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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EOF Thomas Weber / @2022
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