U.S. Flag Official website of the Department of Homeland Security
U.S. Department of Homeland Security Seal. ICS-CERT. Industrial Control Systems Cyber Emergency Response Team.

Advisory (ICSA-18-025-02B)

Siemens Desigo PXC (Update B)

Original release date: January 25, 2018 | Last revised: March 22, 2018

Legal Notice

All information products included in http://ics-cert.us-cert.gov are provided "as is" for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained within. DHS does not endorse any commercial product or service, referenced in this product or otherwise. Further dissemination of this product is governed by the Traffic Light Protocol (TLP) marking in the header. For more information about TLP, see http://www.us-cert.gov/tlp/.

CVSS v3 9.8

ATTENTION: Exploitable remotely/low skill level to exploit.

Vendor: Siemens

Equipment: Desigo PXC

Vulnerability: Improper Authentication


This updated advisory is a follow-up to the updated advisory titled ICSA-18-025-02A Siemens Desigo PXC that was published February 6, 2018, on the NCCIC/ICS-CERT website.


--------- Begin Update B Part 1 of 1 --------

This advisory covers only the Desigo PX Controller product line and not the Apogee PX Controller product line.

--------- End Update B Part 1 of 1 ----------

Siemens reports that the vulnerability affects the following versions of Desigo PXC:

  • Desigo Automation Controllers Compact PXC12/22/36-E.D all versions prior to V6.00.204,
  • Desigo Automation Controllers Modular PXC00/50/100/200-E.D all versions prior to V6.00.204,
  • Desigo Automation Controllers PXC00/64/128-U with Web module all versions prior to V6.00.204,
  • Desigo Automation Controllers for Integration PXC001-E.D all versions prior to V6.00.204, and
  • Desigo Operator Unit PXM20-E all versions prior to V6.00.204


Successful exploitation of this vulnerability could allow unauthenticated remote attackers to upload malicious firmware without prior authentication.


Siemens has provided an updated version that fixes the vulnerability for the affected products. Siemens recommends users update to the newest version V6.00.204 or a later version that can be obtained from Siemens customer support or a local partner.

As a general security measure, Siemens strongly recommends protecting network access to the devices with appropriate mechanisms. Siemens advises configuring the environment according to Siemens operational guidelines in order to run the devices in a protected IT environment.


For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-824231 at the following location:


NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

  • Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
  • Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
  • When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available in the NCCIC Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to NCCIC for tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability.



A remote attacker with network access to the device could potentially upload a new firmware image to the devices without prior authentication.

CVE-2018-4834 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).


Can Demirel and Melih Berk Eksioglu from Biznet Bilisim reported this vulnerability to Siemens.


Critical Infrastructure Sector: Commercial Facilities

Countries/Areas Deployed: Worldwide

Company Headquarters Location: Germany

Contact Information

For any questions related to this report, please contact the NCCIC at:

Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  http://ics-cert.us-cert.gov 
or incident reporting:  https://ics-cert.us-cert.gov/Report-Incident?

The NCCIC continuously strives to improve its products and services. You can help by choosing one of the links below to provide feedback about this product.

Was this document helpful?  Yes  |  Somewhat  |  No

Back to Top