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AUSCERT External Security Bulletin Redistribution
ESB-2021.3345.2
Advisory (icsa-21-280-04) Mitsubishi Electric MELSEC iQ-R
Series C Controller Module
8 July 2022
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Mitsubishi Electric MELSEC iQ-R Series C Controller Module
Publisher: ICS-CERT
Operating System: Network Appliance
Resolution: Patch/Upgrade
CVE Names: CVE-2021-20600
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-21-280-04
Comment: CVSS (Max): 6.8 CVE-2021-20600 (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H)
CVSS Source: ICS-CERT
Calculator: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
Revision History: July 8 2022: Vendor updated advisory and released update
October 8 2021: Initial Release
- --------------------------BEGIN INCLUDED TEXT--------------------
ICS Advisory (ICSA-21-280-04)
Mitsubishi Electric MELSEC iQ-R Series C Controller Module (Update B)
Original release date: July 07, 2022
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 6.8
o ATTENTION: Exploitable remotely
o Vendor: Mitsubishi Electric
o Equipment: MELSEC iQ-R Series C Controller Module R12CCPU-V
o Vulnerability: Uncontrolled Resource Consumption
2. UPDATE INFORMATION
This updated advisory is a follow-up to the original advisory titled
ICSA-21-280-04 Mitsubishi Electric MELSEC iQ-R Series C Controller Module that
was published October 7, 2021, to the ICS webpage on us-cert.cisa.gov.
3. RISK EVALUATION
Successful exploitation of this vulnerability could prevent the module from
starting up. If successfully exploited, a system reset would be required for
recovery.
4. TECHNICAL DETAILS
4.1 AFFECTED PRODUCTS
The following modules of the MELSEC iQ-R Series C Controller Module are
affected:
- --------- Begin Update B Part 1 of 2 ---------
o R12CCPU-V: All versions
- --------- End Update B Part 1 of 2 ---------
4.2 VULNERABILITY OVERVIEW
4.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400
The potential for a denial-of-service condition exists in MELSEC iQ-R series C
Controller Module due to uncontrolled resource consumption caused by an
attacker sending a large number of packets to the module at start up in a short
time.
CVE-2021-20600 has been assigned to this vulnerability. A CVSS v3 base score of
6.8 has been calculated; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:N/S:C/
C:N/I:N/A:H ).
4.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Japan
4.4 RESEARCHER
Mitsubishi Electric Corporation reported this vulnerability to CISA.
5. MITIGATIONS
- --------- Begin Update B Part 2 of 2 ---------
Mitsubishi Electric recommends users update affected devices to Firmware
Version 17 or later. For specific update instructions and additional details
see the Mitsubishi Electric advisory .
- --------- End Update B Part 2 of 2 ---------
If a System WDT error occurs at start up, there is a possibility the C
Controller Module has been attacked. In this case, disconnect the LAN cable of
the module and restart. After confirming the module has started normally, make
a LAN connection.
Regardless of whether the above error occurred, Mitsubishi Electric recommends
users take the following mitigation measures to minimize the risk of exploiting
this vulnerability:
o Use a firewall or virtual private network (VPN), etc. to prevent
unauthorized access when Internet access is required.
o Use within a LAN and block access from untrusted networks and hosts through
firewalls.
For specific update instructions and additional details see the Mitsubishi
Electric advisory .
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 VPNs may have vulnerabilities and should be
updated to the most current version available. Also recognize VPN is only
as secure as its 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.
CISA also recommends users take the following measures to protect themselves
from social engineering attacks:
o Do not click web links or open unsolicited attachments in email messages.
o Refer to Recognizing and Avoiding Email Scams for more information on
avoiding email scams.
o Refer to Avoiding Social Engineering and Phishing Attacks for more
information on social engineering attacks.
No known public exploits specifically target this vulnerability. This
vulnerability has a high attack complexity.
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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