ICS Advisory

3S CODESYS Gateway Null Pointer Exception Vulnerability

Last Revised
Alert Code


Ashish Kamble of Qualys, Inc has identified a null pointer exception vulnerability in 3S-Smart Software Solutions GmbH’s CODESYS Gateway Server. 3S-Smart Software Solutions GmbH has produced a new version to mitigate this vulnerability. Ashish Kamble has tested the new version to validate that it resolves the vulnerability.

This vulnerability could be exploited remotely.


The following Gateway Server versions are affected:

  • CODESYS Gateway Server, Version and prior versions.


Null pointer exceptions cause the server to crash creating a denial of service.

Impact to individual organizations depends on many factors that are unique to each organization. NCCIC/ICS-CERT recommends that organizations evaluate the impact of this vulnerability based on their operational environment, architecture, and product implementation.


3S-Smart Software Solutions GmbH is headquartered in Kempten, Germany, and has distributors in more than 10 countries worldwide.

The affected product, CODESYS Gateway Server, is a software-defined server. This server is primarily found in the Critical Manufacturing and Energy sectors. 3S-Smart Software Solutions GmbH estimates that these products are used worldwide.



NULL POINTER EXCEPTIONCWE-476: NULL Pointer Dereference, http://cwe.mitre.org/data/definitions/476.html, web site last accessed October 20, 2015.

The server fails in handling certain HTTP POST/GET requests leading to a null pointer exception causing the server process to crash. The result of the crash would be a denial of service.

CVE-2015-6484NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-6484, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory. has been assigned to this vulnerability. A CVSS v3 base score of 7.5 and a temporal score of 6.5 have been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:R).CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:R, web site last accessed October 20, 2015.



This vulnerability could be exploited remotely.


No known public exploits specifically target this vulnerability.


An attacker with a low skill would be able to exploit this vulnerability.


3S-Smart Software Solutions GmbH has released a new version of CODESYS, Version, which addresses the null pointer exception vulnerability. CODESYS, Version is available at the following location with a valid user account:

https://www.codesys.com/download/download-center.html (link is external)

For additional information about the new version of CODESYS or questions about the vulnerability, the CODESYS Support Team’s contact information is as follows:


ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of these vulnerabilities. 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.

ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT web page at: http://ics-cert.us-cert.gov/content/recommended-practices. 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 ICS‑CERT 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 (http://ics-cert.us-cert.gov/).

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


3S-Smart Software Solutions