ICS Advisory (ICSA-21-068-05)

Siemens LOGO! 8 BM

Click to Tweet.
Click to send to Facebook.
Click to Share.

Legal Notice

All information products included in https://us-cert.cisa.gov/ics 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 https://us-cert.cisa.gov/tlp/.


 

1. EXECUTIVE SUMMARY

  • CVSS v3 5.5
  • ATTENTION: Low skill level to exploit
  • Vendor: Siemens
  • Equipment: LOGO! 8 BM
  • Vulnerability: Improper Handling of Exceptional Conditions

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service condition if a user is tricked into loading a malicious project file.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of LOGO! 8, a programmable logic controller, are affected:

  • LOGO! 8 BM (incl. SIPLUS variants): All versions

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER HANDLING OF EXCEPTIONAL CONDITIONS CWE-755

Control logic (CL) the LOGO! 8 could be manipulated in a way to cause the device executing the CL to improperly handle the manipulation and crash, resulting in a denial-of-service condition. The device must then be manually reset.

CVE-2020-25236 has been assigned to this vulnerability. A CVSS v3 base score of 5.5 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).

3.3 BACKGROUND

  • CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities, Transportation Systems
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Max Bäumler reported this vulnerability to Siemens.

4. MITIGATIONS

Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:

  • Siemens recommends limiting the possibilities to execute untrusted code if possible.

As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security and following the recommendations in the product manuals.

Additional information on industrial security for Siemens devices can be found at: https://www.siemens.com/industrialsecurity

For more information, please see Siemens Security Advisory SSA-783481

CISA also recommends users take the following measures to protect themselves from social engineering attacks:

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

CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.cisa.gov. 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 on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

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

No known public exploits specifically target this vulnerability. This vulnerability is not exploitable remotely.


Contact Information

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

Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  https://us-cert.cisa.gov/ics 
or incident reporting:  https://us-cert.cisa.gov/report

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

This product is provided subject to this Notification and this Privacy & Use policy.

Please share your thoughts.

We recently updated our anonymous product survey; we'd welcome your feedback.