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TLP:WHITE

Advisory (ICSA-15-258-02)

3S CODESYS Gateway Server Buffer Overflow Vulnerability

Original release date: September 15, 2015

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OVERVIEW

NCCIC/ICS-CERT received a report from HP’s Zero Day Initiative (ZDI) concerning a heap-based buffer overflow vulnerability in 3S-Smart Software Solutions GmbH’s CODESYS Gateway Server. This vulnerability was reported to ZDI by security researcher Josep Pi Rodriguez. 3S-Smart Software Solutions GmbH has produced a new version to mitigate this vulnerability.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

The following Gateway Server versions are affected:

  • CODESYS Gateway Server, Version 2.3.9.46 and prior versions.

IMPACT

Successful exploitation of this vulnerability could cause a buffer overflow condition that may allow remote code execution.

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

BACKGROUND

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 product is primarily found in products in the Critical Manufacturing and Energy sectors. 3S-Smart Software Solutions GmbH estimates that these products are used worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

HEAP-BASED BUFFER OVERFLOWa

Multiple heap-based buffer overflow vulnerabilities have been identified which may allow remote code execution.

CVE-2015-6460b has been assigned to this vulnerability. ZDI has assigned a CVSS v2 base score of 7.5; the CVSS vector string is (AV:N/AC:L/Au:N/C:P/I:P/A:P).c

VULNERABILITY DETAILS

EXPLOITABILITY

This vulnerability could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target this vulnerability.

DIFFICULTY

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

MITIGATION

3S-Smart Software Solutions GmbH has released a new version of CODESYS, Version 2.3.9.47, which addresses the heap-based buffer overflow vulnerability. CODESYS, Version 2.3.9.47 is available at the following location with a valid user account:

https://www.codesys.com/download/download-center.html

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

https://www.codesys.com/support-training/codesys-support/inquiry-per-phone-e-mail.html

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

  • Using application whitelisting will not prevent memory-based attacks, such as exploiting buffer overflows vulnerabilities, but it can prevent shellcode from running executables that have not been authorized, thereby limiting the impact of memory-based attacks that call files.
  • 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.


Contact Information

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

Email: NCCICCUSTOMERSERVICE@hq.dhs.gov
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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