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AUSCERT External Security Bulletin Redistribution
ESB-2020.4042
Advisory (icsa-20-315-03) Schneider Electric PLC Simulator
for EcoStruxure Control Expert
13 November 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: Schneider Electric PLC Simulator for EcoStruxure Control Expert
Publisher: ICS-CERT
Operating System: Network Appliance
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2020-7538
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-20-315-03
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ICS Advisory (ICSA-20-315-03)
Schneider Electric PLC Simulator for EcoStruxure Control Expert
Original release date: November 10, 2020
Legal Notice
All information products included in https://us-cert.cisa.gov/ics are
provided"as is" for informational purposes only. The Department of Homeland
Security (DHS) does not provide any warranties of any kind regarding any
information contained within. DHS does not endorse any commercial product or
service, referenced in this product or otherwise. Further dissemination of this
product is governed by the Traffic Light Protocol (TLP) marking in the header.
For more information about TLP, see https://us-cert.cisa.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 7.5
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Schneider Electric
o Equipment: PLC Simulator for EcoStruxure Control Expert
o Vulnerability: Improper Check for Unusual or Exceptional Conditions
2. RISK EVALUATION
Successful exploitation of this vulnerability could cause a denial-of-service
condition, which could result in a failure of the EcoStruxture Control Expert
Simulator.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Schneider Electric reports the vulnerability affects the following PLC
simulators:
o PLC Simulator for EcoStruxure Control Expert, all versions
o PLC Simulator for Unity Pro (former name of EcoStruxure Control Expert),
all versions
3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER CHECK FOR UNUSUAL OR EXCEPTIONAL CONDITIONS CWE-754
A vulnerability exists that could cause a crash of the PLC simulator present in
EcoStruxure Control Expert software when receiving a specially crafted request
over Modbus.
CVE-2020-7538 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 ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities, Energy, Food and
Agriculture, Government Facilities, Transportation Systems, Water and
Wastewater Systems
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: France
3.4 RESEARCHER
Parity Dynamics Research Team reported this vulnerability to CISA.
4. MITIGATIONS
Schneider Electric has released Version 15.0 of the EcoStruxure Control Expert
software to mitigate this vulnerability. It is available for download on the
Schneider Electric website .
After downloading the fix, the following step is required to mitigate the
vulnerability:
o In the option dialog box of the PLC simulator, set the listening IP Address
to 127.0.0.1 (localhost), which will prevent remote network connections to
the PLC simulator.
The default listening IP address is: 0.0.0.0. The default setting exposes the
PLC to the vulnerability described in this advisory.
Schneider Electric recommends using appropriate patching methodologies when
applying these patches. It also strongly recommends the use of back-ups and
evaluating the impact of these patches in a test and development environment or
on offline infrastructure. Contact Schneider Electric's Customer Care Center
for assistance removing a patch.
If users choose not to apply the remediation provided above, they should
immediately apply the following mitigations to reduce the risk of exploit:
o Set up network segmentation and implement a firewall to block all
unauthorized access to Port 502/TCP
o Harden the engineering workstation running PLC Simulator for EcoStruxure
Control Expert
o Follow workstation, network, and site-hardening guidelines in the
Cybersecurity Best Practices guide .
Please see Schneider Electric Security Notification number SEVD-2020-315-01 for
more information.
CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
o Minimize network exposure for all control system devices and/or systems,
and ensure that they are not accessible from the Internet .
o Locate control system networks and remote devices behind firewalls, and
isolate them from the business network.
o 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.
CISA reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices
on the ICS webpage on us-cert.cisa.gov . 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
on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation
Strategies .
Organizations observing any suspected malicious activity should follow their
established internal procedures and report their findings to CISA for tracking
and correlation against other incidents.
No known public exploits specifically target this vulnerability.
For any questions related to this report, please contact the CISA at:
Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870
CISA continuously strives to improve its products and services. You can help by
choosing one of the links below to provide feedback about this product.
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