ICS Advisory

IRZ RUH2 3G Firmware Overwrite Vulnerability (Update A)

Last Revised
Alert Code


This updated advisory is a follow-up to the original advisory titled ICSA-16-138-01 iRZ RUH2 3G Firmware Overwrite Vulnerability that was published May 17, 2016, on the NCCIC/ICS-CERT web site.

ICS-CERT has identified a firmware overwrite vulnerability in iRZ’s RUH2 device. iRZ has discontinued this product and no longer offers support.

This vulnerability could be exploited remotely. Exploits that target this vulnerability are known to be publicly available.


The following iRZ product is affected:

  • RUH2


An attacker could corrupt the firmware of the serial-to-Ethernet converters employed for substation communications and network routers.

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.


iRZ is a Russian-based company that maintains offices in several countries around the world, including China, Iran, Ukraine, Kazakhstan, France, Belgium, Switzerland, Italy, and Spain.

The affected product, RUH2, is a serial-to-network connector system. According to iRZ, RUH2s are deployed across several sectors including Commercial Facilities, Communications, Financial Services, Healthcare and Public Health, and others. iRZ estimates that this product is used primarily in Eastern Europe.



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

UNRESTRICTED UPLOAD OF FILECWE-434: Unrestricted Upload of File with Dangerous Type, http://cwe.mitre.org/data/definitions/434.html, web site last accessed December 22, 2016.

Authorized users can remotely update the firmware with an unvalidated patch.

CVE-2016-2309NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-2309, web site last accessed December 22, 2016. has been assigned to this vulnerability. A CVSS v3 base score of 7.2 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H).CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, web site last accessed December 22, 2016.

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



This vulnerability could be exploited remotely.


Exploits that target this vulnerability are publicly available.


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


iRZ recommends users replace the RUH2 with either the RUH2b or RUH3. Additional information on this vulnerability is available at:


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

This product is provided subject to this Notification and this Privacy & Use policy.