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Advisory (ICSA-16-336-02A)

Moxa NPort Device Vulnerabilities (Update A)

Original release date: December 01, 2016 | Last revised: March 21, 2017

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This updated advisory is a follow-up to the original advisory titled ICSA-16-336-02 Moxa NPort Device Vulnerabilities that was published December 1, 2016, on the NCCIC/ICS-CERT web site.

Security researchers Reid Wightman of RevICS Security, Mikael Vingaard, and Maxim Rupp have identified vulnerabilities in Moxa’s NPort serial device servers. Moxa has produced new firmware versions to mitigate these vulnerabilities.

These vulnerabilities could be exploited remotely.


--------- Begin Update A Part 1 of 2 --------

Moxa reports that the vulnerability affects the following versions of NPort:

  • NPort 5110 versions prior to 2.7,
  • NPort 5130/5150 Series versions prior to 3.7,
  • NPort 5200 Series versions prior to 2.9,
  • NPort 5400 Series versions prior to 3.12,
  • NPort 5600 Series versions prior to 3.8,
  • NPort 5100A Series & NPort P5150A versions prior to 1.4,
  • NPort 5200A Series versions prior to 1.4,
  • NPort 5150AI-M12 Series versions prior to 1.3,
  • NPort 5250AI-M12 Series versions prior to 1.3,
  • NPort 5450AI-M12 Series versions prior to 1.3,
  • NPort 5600-8-DT Series versions prior to 2.5,
  • NPort 5600-8-DTL Series versions prior to 2.5,
  • NPort IA5450A versions prior to v1.4,
  • NPort 6000 series versions prior to 1.16, and
  • NPort 6110 series all versions

--------- End Update A Part 1 of 2 ----------


Successful exploitation of these vulnerabilities could lead to the complete compromise of an affected system.

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


Moxa is a Taiwan-based company that maintains offices in several countries around the world, including the US, UK, India, Germany, France, China, Russia, and Brazil.

The affected products, NPort devices, connect serial devices to Ethernet networks. According to Moxa, NPort devices are deployed across several sectors including Critical Manufacturing, Energy, and Transportation Systems. Moxa estimates that these products are used worldwide.




Administration passwords can be retried without authenticating.

CVE-2016-9361b has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).c


Firmware can be updated over the network without authentication, which may allow remote code execution.

CVE-2016-9369e has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).f


Buffer overflow vulnerability may allow an unauthenticated attacker to remotely execute arbitrary code.

CVE-2016-9363h has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L).i


User-controlled input is not neutralized before being output to web page.

CVE-2016-9371k has been assigned to this vulnerability. A CVSS v3 base score of 6.1 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).l


Requests are not verified to be intentionally submitted by the proper user.

CVE-2016-9365n has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).o


An attacker can freely use brute force to determine parameters needed to bypass authentication.

CVE-2016-9366q has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).r


A configuration file contains parameters that represent passwords in plaintext.

CVE-2016-9348t has been assigned to this vulnerability. A CVSS v3 base score of 3.3 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N).u


The amount of resources requested by a malicious actor is not restricted, leading to a denial-of-service caused by resource exhaustion.

CVE-2016-9367w has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).x



These vulnerabilities could be exploited remotely.


No known public exploits specifically target these vulnerabilities.


An attacker with low skill would be able to exploit these vulnerabilities.


--------- Begin Update A Part 2 of 2 --------

Moxa has released new firmware versions, which address the identified vulnerabilities in all but one of the affected NPort devices. Moxa recommends installing the new firmware version.

  • NPort 5110 Version 2.7:


  • NPort 5130/5150 Series Version 3.7:


  • NPort 5200 Series Version 2.9:


  • NPort 5400 Series Version 3.12:


  • NPort 5600 Series Version 3.8:


  • NPort 5100A Series & NPort P5150A Version 1.4:


  • NPort 5200A Series Version 1.4:


  • NPort 5150AI-M12 Series Version 1.3:


  • NPort 5250AI-M12 Series Version 1.3:


  • NPort 5450AI-M12 Series Version 1.3:


  • NPort 5600-8-DT Series Version 2.5:


  • NPort 5600-8-DTL Series Version 1.4:


  • NPort IA5450A Version 1.4:


  • NPort 6000 Series Version 1.16:


--------- End Update A Part 2 of 2 ----------

Moxa has reported that the NPort 6110 device was discontinued in December 2008 and will not have patches released to address these vulnerabilities. Moxa recommends that customers using the NPort 6110 should upgrade the affected device.

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

  • Ensure that Ports 161/UDP, 4800/UDP, and 4900/TCP are only accessible by trusted systems and that restricting access to Ports 4800/UDP and 4900/TCP will impact remote systems administration.
  • Ensure that all unused ports are disabled.
  • 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.

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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