ICS Advisory (ICSA-19-227-04)


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  • CVSS v3 7.5
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Siemens
  • Equipment: SINAMICS
  • Vulnerability: Uncontrolled Resource Consumption


Successful exploitation of this vulnerability may allow an attacker to perform a denial-of-service attack.



Siemens reports the vulnerability affects webservers of the following industrial products: 

  • SINAMICS GH150 v4.7 (Control Unit): All versions
  • SINAMICS GH150 v4.8 (Control Unit): All versions prior to v4.8 SP2 HF6
  • SINAMICS GL150 v4.7 (Control Unit): All versions
  • SINAMICS GL150 v4.8 (Control Unit): All versions prior to v4.8 SP2 HF7
  • SINAMICS GM150 v4.7 (Control Unit): All versions
  • SINAMICS GM150 v4.8 (Control Unit): All versions prior to v4.8 SP2 HF9
  • SINAMICS SL150 v4.7 (Control Unit): All versions
  • SINAMICS SL150 v4.8 (Control Unit): All versions
  • SINAMICS SM120 v4.7 (Control Unit): All versions
  • SINAMICS SM120 v4.8 (Control Unit): All versions
  • SINAMICS SM150 v4.8 (Control Unit): All versions



The webserver of the affected devices contains a vulnerability that may lead to a denial-of-service condition. An attacker may cause a denial-of-service situation, leading to a restart of the webserver of the affected device. The security vulnerability could be exploited by an attacker with network access to the affected systems. Successful exploitation requires no system privileges and no user interaction.

CVE-2019-6568 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).


  • CRITICAL INFRASTRUCTURE SECTORS: Chemical, Commercial Facilities, Critical Manufacturing, Energy, Food and Agriculture, Healthcare and Public Health, Transportation Systems, Water and Wastewater Systems


Siemens reported this vulnerability to CISA.


Siemens recommends users update to v4.8 SP2 HF9. The update can be obtained from a Siemens representative or via Siemens customer service.
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:

  • Restrict network access to the integrated webserver.
  • Deactivate the webserver if not required, and if deactivation is supported by the product. For SINAMICS products, webserver may be deactivated with parameter P8986 = 0

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.

Additional information on industrial security by Siemens can be found at:


For more information on the vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-530931 at the following location:


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

  • 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.

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.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.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.

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?

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