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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.4044 Advisory (icsa-20-317-01) Mitsubishi Electric MELSEC iQ-R Series 13 November 2020 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Mitsubishi Electric MELSEC iQ-R Series Publisher: ICS-CERT Operating System: Network Appliance Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2020-5666 Original Bulletin: https://us-cert.cisa.gov/ics/advisories/icsa-20-317-01 - --------------------------BEGIN INCLUDED TEXT-------------------- ICS Advisory (ICSA-20-317-01) Mitsubishi Electric MELSEC iQ-R Series Original release date: November 12, 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 6.8 o ATTENTION: Exploitable remotely o Vendor: Mitsubishi Electric o Equipment: MELSEC iQ-R series o Vulnerability: Uncontrolled Resource Consumption 2. RISK EVALUATION Successful exploitation of this vulnerability could cause a denial-of-service condition for the affected products. 3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS Mitsubishi Electric reports the vulnerability affects the following MELSEC iQ-R series CPU module products: o R00/01/02 CPU Firmware versions from 05 to 19 o R04/08/16/32/120(EN) CPU Firmware versions from 35 to 51 3.2 VULNERABILITY OVERVIEW 3.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400 A denial-of-service vulnerability due to uncontrolled resource consumption exists in MELSEC iQ-R series CPU modules. This vulnerability does not affect products when the "To Use or Not to Use Web Server" parameter of CPU modules is set to "Not Use." The default setting is "Not Use." CVE-2020-5666 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 ). 3.3 BACKGROUND o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing o COUNTRIES/AREAS DEPLOYED: Worldwide o COMPANY HEADQUARTERS LOCATION: Japan 3.4 RESEARCHER Xiaofei.Zhang, a researcher from China, reported this vulnerability to Mitsubishi Electric. 4. MITIGATIONS Mitsubishi Electric has issued the following firmware versions to address this issue: o R00/01/02CPU firmware Versions 20 or later o R04/08/16/32/120(EN)CPU firmware Versions 52 or later Mitsubishi Electric also recommends the following practices: o If the web server function is not needed, change the setting for "To Use or Not to Use Web Server" to "Not Use." o Use a firewall or virtual private network (VPN), etc., to prevent unauthorized access when Internet access is required. o Use within a trusted LAN and block access from untrusted networks and hosts through firewall. For more information about this vulnerability and the associated mitigations, please see the vulnerability information on the Mitsubishi website . 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. High skill level is needed to exploit. 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. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. 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Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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