CVE-2019-6853: Schneider Electric – Andover Continuum Building Management System Controllers XSS

Schneider Electric Security Notification

Document Reference Number – SEVD-2019-316-01 V2.0

Andover Continuum Line of Controllers V2.0

12 November 2019 (27 November 2019)

Schneider Electric is aware of cross-site scripting vulnerability in its line of Andover Continuum
building management system controllers. The controllers act as the system coordinators for the
Continuum I/O modules, providing integrated global control and monitoring, history logging,
local and remote alarming.

Affected Product(s)
Andover Continuum controller models that support the ability to act as their own web server.
The Andover continuum controller models that provided built-in web server capability included,
but were not limited to, the following models 9680, 5740 and 5720, bCX4040, bCX9640, 9900,
9940, 9924, 9702, and 9200 and 9400 series controllers with the Web Server option enabled.

Vulnerability Details
CVE ID: CVE-2019-6853
CVSS v3.0 Base Score 6.1 | (Medium) | CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
A CWE-79 – A Failure to Preserve Web Page Structure vulnerability exists, which could enable
a successful “Cross-site Scripting” (XSS attack) when using the products’ web server.

Since Andover Continuum is a legacy product line from which customers have a clear path to
our new, state of the art EcoStruxure Building Operation, no firmware fix will be provided for this
issue. Rather, the device’s web server should be disabled to reduce risk, using one the methods
• Users of the 9680, 5740 and 5720, bCX4040, bCX9640, and 9702 models of networklevel controllers should disable the web server by setting the web server port to 0 via the
controller web page.
• Users of the 9400, 9410, 9900, 9940 and 9924 models of network controllers should
contact the Schneider Electric support group to obtain a unique file that will allow them to
disable the controllers’ web servers.
• Compensating controls will be needed to isolate its web browser ports, which would
disable the web server. Compensating controls could include incorporating firewalls with
access control lists, deep packet inspection and packet filtering.
A controller reboot is required to complete this operation.

Product Information
This notification applies the Andover Continuum line of building controllers.
Product Category – Building and Automation Control
Learn more about Schneider Electric’s product categories here:
How to determine if you are affected
All customers using the identified Continuum controllers are affected.

General Security Recommendations
We strongly recommend following industry cybersecurity best practices, such as:
• Locate control and safety system networks and remote devices behind firewalls, and
isolate them from the business network.
• Physical controls should be in place so that no unauthorized person would have access
to the ICS and safety controllers, peripheral equipment or the ICS and safety networks.
• All controllers should reside in locked cabinets and never be left in the “Program” mode.
• All programming software should be kept in locked cabinets and should never be
connected to any network other than the network for the devices that it is intended.
• All methods of mobile data exchange with the isolated network such as CDs, USB
drives, etc. should be scanned before use in the terminals or any node connected to
these networks.
• Laptops that have connected to any other network besides the intended network should
never be allowed to connect to the safety or control networks without proper sanitation.
• Minimize network exposure for all control system devices and/or systems, and ensure
that they are not accessible from the Internet.
• 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.

Schneider Electric recognizes the following researcher(s) for identifying and helping to
coordinate a response to this vulnerability:
CVE Researcher(s) Name
CVE-2019-6853 Ken Pyle, DFDR Consulting

For More Information
This document provides an overview of the identified vulnerability or vulnerabilities and actions
required to mitigate. For more details and assistance on how to protect your installation, please
contact your local Schneider Electric representative and/or Schneider Electric Industrial
Cybersecurity Services. These organizations will be fully aware of this situation and can support
you through the process.