1. EXECUTIVE SUMMARY
- CVSS v3 8.6
- ATTENTION: Exploitable remotely/low skill level to exploit
- Vendor: Mitsubishi Electric
- Equipment: MELSEC iQ-R Series
- Vulnerability: Uncontrolled Resource Consumption
2. UPDATE INFORMATION
This updated advisory is a follow-up to the advisory update titled ICSA-20-282-02 Mitsubishi Electric MELSEC iQ-R Series (Update A) that was published October 29, 2020, to the ICS webpage on us-cert.cisa.gov.
3. RISK EVALUATION
Successful exploitation of this vulnerability could result in a denial-of-service condition due to uncontrolled resource consumption.
4. TECHNICAL DETAILS
4.1 AFFECTED PRODUCTS
The following MELSEC iQ-R series modules are affected:
- R00/01/02CPU, Firmware Versions 20 and earlier
- R04/08/16/32/120(EN)CPU, Firmware Versions 52 and earlier
- R08/16/32/120SFCPU, Firmware Versions 22 and earlier
——— Begin Update B Part 1 of 2 ———
- R08/16/32/120PCPU, Firmware Versions 25 and earlier
——— End Update B Part 1 of 2 ———
- R16/32/64MTCPU, All versions
4.2 VULNERABILITY OVERVIEW
4.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400
An uncontrolled resource consumption (CWE-400) vulnerability resulting in a denial-of-service condition may be caused when an attacker sends specially crafted packets to MELSEC iQ-R series modules.
CVE-2020-16850 has been assigned to this vulnerability. A CVSS v3 base score of 8.6 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H).
4.3 BACKGROUND
- CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Japan
4.4 RESEARCHER
Yossi Reuven of SCADAfence reported this vulnerability to Mitsubishi Electric.
5. MITIGATIONS
The following modules have been patched:
- R00/01/02CPU: Firmware Versions 21 or later
- R04/08/16/32/120CPU, R04/08/16/32/120ENCPU: Firmware Versions 53 or later
- R08/16/32/120SFCPU: Firmware Versions 23 or later
——— Begin Update B Part 2 of 2 ———
- R08/16/32/120PCPU: Firmware Versions 26 or later
——— End Update B Part 2 of 2 ———
Mitsubishi Electric plans to release a patch during the coming months, and this publication will be updated with that patch information once available. Please contact a Mitsubishi Electric representative for additional details.
Mitsubishi Electric recommends users take the following mitigation measures to minimize the risk of exploiting this vulnerability:
- Use a firewall or virtual private network (VPN), etc., to prevent unauthorized access if Internet access is required.
- Use within a LAN and block access from untrusted networks and hosts through firewalls.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
- Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
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.
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