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 5.3
- ATTENTION: Exploitable remotely/low skill level to exploit
- Vendor: Siemens
- Equipment: SIMATIC Controller Web Servers
- Vulnerability: Uncaught Exception
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service condition.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Siemens reports the vulnerability affects the web server of the following SIMATIC controllers:
- SIMATIC ET 200SP Open Controller (incl. SIPLUS variants): Version 20.8
- SIMATIC S7-1500 Software Controller: Version 20.8
3.2 VULNERABILITY OVERVIEW
An attacker can send a specially crafted HTTP request to the products web server, which may cause a denial-of-service condition.
- CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Germany
Siemens reported this vulnerability to CISA.
Siemens has released updates for the affected products and recommends updating to the latest version:
- SIMATIC ET 200SP Open Controller (incl. SIPLUS variants): Update to v21.8
- SIMATIC S7-1500 Software Controller: Update to v21.8
Siemens notes that if the PC Station web server does not restart automatically, a Windows reboot is required. This can be done while the control system is running as the PLC control functionality is not affected.
As a general security measure, Siemens strongly recommends users protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure the environment according to Siemens’ operational guidelines for industrial security and follow the recommendations in the product manuals.
For more information, please see Siemens Security Advisory SSA-700697
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.
For any questions related to this report, please contact the CISA at:
Toll Free: 1-888-282-0870
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.
Please share your thoughts.
We recently updated our anonymous product survey; we'd welcome your feedback.