Schneider Electric Invensys Positioner Buffer Overflow Vulnerability
ICSA： ICS Advisory (ICSA-15-055-03)
Ivan Sanchez from Nullcode Team has identified a buffer overflow security vulnerability in the DTM (Device Type Manager) software for Schneider Electric’s Invensys SRD Control Valve Positioner product line. Schneider Electric has produced a new version that mitigates this vulnerability.
The following Schneider Electric products are affected:
- DTM Version 3.1.6 and all previous versions used with SRD 960 and SRD 991 Control Valve Positioners.
An attacker who exploits this vulnerability may be able to execute arbitrary code.
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.
Schneider Electric’s corporate headquarters is located in Paris, France, and maintains offices in more than 100 countries worldwide.
The affected products, SRD 960 and SRD 991 Control Valve Positioners, operate pneumatic valve actuators. According to Schneider Electric, these products are deployed across several sectors including Critical Manufacturing, Energy, Water and Wastewater Systems, and others. Schneider Electric estimates that these products are used globally.
STACK-BASED BUFFER OVERFLOWa
The vulnerability identified includes a stack buffer overflow condition in a DLL file that could possibly result in remote code execution.
This vulnerability is not exploitable remotely and cannot be exploited without user interaction. The exploit is only triggered when a local user runs the vulnerable application and loads the malformed DLL file.
EXISTENCE OF EXPLOIT
No known public exploits specifically target this vulnerability.
Crafting a working exploit for this vulnerability would be difficult. Social engineering is required to convince the user to accept the malformed DLL file. Additional user interaction is needed to load the malformed file. This decreases the likelihood of a successful exploit.
Schneider Electric encourages customers using these products to download the latest version, V3.6.3, that mitigates this vulnerability. It can be found at the bottom of the following web site:
Schneider Electric’s security notice SEVD-2015-050-01 is available at the following location:
ICS-CERT encourages asset owners to take additional defensive measures to protect against this and other cybersecurity risks.
- 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 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. ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
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.
In addition, ICS-CERT recommends that users take the following measures to protect themselves from social engineering attacks:
- Do not click web links or open unsolicited attachments in email messages.
- Refer to Recognizing and Avoiding Email Scamsd for more information on avoiding email scams.
- Refer to Avoiding Social Engineering and Phishing Attackse for more information on social engineering attacks.
- a. CWE-121: Stack-based Buffer Overflow, http://cwe.mitre.org/data/definitions/121.html, web site last accessed February 24, 2015.
- b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-9206, 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:L/AC:H/Au:N/C:P/I:P/A:C, web site last accessed February 24, 2015.
- d. Recognizing and Avoiding Email Scams, http://www.us-cert.gov/reading_room/emailscams_0905.pdf, web site last accessed February 24, 2015.
- e. National Cyber Alert System Cyber Security Tip ST04-014, http://www.us-cert.gov/cas/tips/ST04-014.html, web site last accessed February 24, 2015.