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Advisory (ICSA-17-054-03)

Schneider Electric Modicon M340 PLC

Original release date: February 23, 2017

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CVSS v3 7.5

ATTENTION: Remotely exploitable/low-skill level to exploit

Vendor: Schneider Electric

Equipment: Modicon M340 PLC

Vulnerability: Resource Exhaustion


Schneider Electric reports that the vulnerability affects the following Modicon PLC products with firmware versions prior to Version 2.9:

  • BMXNOC0401,
  • BMXNOE0100,
  • BMXNOE0110,
  • BMXNOE0110H,
  • BMXNOR0200H,
  • BMXP341000,
  • BMXP342000,
  • BMXP3420102,
  • BMXP3420102CL,
  • BMXP342020,
  • BMXP342020H,
  • BMXP342030,
  • BMXP3420302,
  • BMXP3420302H, and
  • BMXP342030H.


Successful exploitation of this vulnerability may render the device unresponsive requiring a physical reset of the PLC.


Schneider Electric has released a new firmware version, Version 2.9, to mitigate the identified vulnerability, which is available at the following location:


Schneider Electric recommends that users upgrade to the latest firmware version.

NCCIC/ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of this vulnerability. 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. 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.

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.

No known public exploits specifically target this vulnerability. This vulnerability is not remotely exploitable.


A remote attacker could send a specially crafted set of packets to the PLC causing it to freeze, requiring the operator to physically press the reset button on the PLC in order to recover.

CVE-2017-6017 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).


Luis Francisco Martin Liras reported the issue to Schneider Electric.


Critical Infrastructure Sector(s): Defense Industrial Base; Energy; Government Facilities; Nuclear Reactors, Materials, and Waste; Transportation Systems; Water and Wastewater Systems

Countries/Areas Deployed: United States, China, Russia, and India.

Company Headquarters Location: Paris, France

Contact Information

For any questions related to this report, please contact ICS-CERT at:

Email: ics-cert@hq.dhs.gov
Toll Free: 1-877-776-7585
International Callers: (208) 526-0900

For industrial control systems security information and incident reporting: http://ics-cert.us-cert.gov

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