3S CODESYS Gateway Server Buffer Overflow Vulnerability
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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.
The following Gateway Server versions are affected:
- CODESYS Gateway Server, Version 220.127.116.11 and prior versions.
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.
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.
HEAP-BASED BUFFER OVERFLOWa
Multiple heap-based buffer overflow vulnerabilities have been identified which may allow remote code execution.
This vulnerability could be exploited remotely.
EXISTENCE OF EXPLOIT
No known public exploits specifically target this vulnerability.
An attacker with low skill would be able to exploit this vulnerability.
3S-Smart Software Solutions GmbH has released a new version of CODESYS, Version 18.104.22.168, which addresses the heap-based buffer overflow vulnerability. CODESYS, Version 22.214.171.124 is available at the following location with a valid user account:
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:
- 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.
- a. CWE-122: Heap-based Buffer Overflow, http://cwe.mitre.org/data/definitions/122.html, web site last accessed September 15, 2015.
- b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-6460, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory.
- c. CVSS Calculator, http://nvd.nist.gov/cvss.cfm?version=2&vector=AV:N/AC:L/Au:N/C:P/I:P/A:P, web site last accessed September 15, 2015.
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