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Advisory (ICSA-16-061-02)

Rockwell Automation Allen-Bradley CompactLogix Reflective Cross-Site Scripting Vulnerability

Original release date: March 01, 2016 | Last revised: March 02, 2016

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This advisory is a follow-up to the alert titled ICS-ALERT-15-225-01A Rockwell Automation 1766-L32 Series Vulnerabilitya that was published August 13, 2015, on the NCCIC/ICS-CERT web site.

Independent researcher Aditya Sood has identified a cross-site scripting vulnerability in Rockwell Automation’s CompactLogix controller. This vulnerability has been publicly disclosed. Rockwell Automation has produced a new firmware version to mitigate this vulnerability.

This vulnerability could be exploited remotely.


Rockwell Automation reports that the vulnerability affects the following versions of the Allen‑Bradley CompactLogix controller platform:

  • 1769-L16ER-BB1B, Version 27.011 and earlier,
  • 1769-L18ER-BB1B, Version 27.011 and earlier,
  • 1769-L18ERM-BB1B, Version 27.011 and earlier,
  • 1769-L24ER-QB1B, Version 27.011 and earlier,
  • 1769-L24ER-QBFC1B, Version 27.011 and earlier,
  • 1769-L27ERM-QBFC1B, Version 27.011 and earlier,
  • 1769-L30ER, Version 27.011 and earlier,
  • 1769-L30ERM, Version 27.011 and earlier,
  • 1769-L30ER-NSE, Version 27.011 and earlier,
  • 1769-L33ER, Version 27.011 and earlier,
  • 1769-L33ERM, Version 27.011 and earlier,
  • 1769-L36ERM, Version 27.011 and earlier,
  • 1769-L23E-QB1B, Version 20.018 and earlier (Will be discontinued in June 2016), and
  • 1769-L23E-QBFC1B, Version 20.018 and earlier (Will be discontinued in June 2016).


A successful exploit using this vulnerability could affect the availability of the target device.

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.


Rockwell Automation is a US-based company that maintains offices around the world.

The affected products, CompactLogix, are controllers that include a web server. According to Rockwell Automation, these products are deployed across several sectors including Chemical, Critical Manufacturing, Food and Agriculture, Water and Wastewater Systems, and others. Rockwell Automation estimates that these products are used worldwide.




The vulnerability in the CompactLogix’s webserver allows an attacker to inject arbitrary JavaScript into an unsuspecting user’s web browser. The target of this type of attack is not the CompactLogix itself. Instead, the CompactLogix is a vehicle to deliver an attack to the web browser.

CVE-2016-2279c has been assigned to this vulnerability. A CVSS v3 base score of 6.1 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).d



This vulnerability could be exploited remotely.


This vulnerability was publicly disclosed; it is unknown if there are public exploits that specifically target this vulnerability.


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


Rockwell Automation recommends that users of 1769-L23E-QB1B migrate to 1769-L24ER-BB1B and users of 1769-L23E-QBFC1B migrate to 1769-L24ER-QBFC1B.

For the other affected versions listed above, Rockwell Automation recommends that users apply firmware Version 28.011+ available at:


For more detailed information, please see Rockwell Automation’s security notification (KB731098 ) at the following URL, with a valid account:


Rockwell Automation also recommends the following security practices:

  • Use trusted software, software patches, antivirus/antimalware programs and interact only with trusted web sites and attachments.
  • Employ training and awareness programs to educate users on the warning signs of a phishing or social engineering attack.
  • 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 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.

Contact Information

For any questions related to this report, please contact the NCCIC at:

Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  http://ics-cert.us-cert.gov 
or incident reporting:  https://ics-cert.us-cert.gov/Report-Incident?

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