1. EXECUTIVE SUMMARY
- CVSS v3 7.5
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: Mitsubishi Electric
- Equipment: MELSEC and MELIPC Series
- Vulnerabilities: Uncontrolled Resource Consumption, Improper Handling of Length Parameter Inconsistency, Improper Input Validation
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow a remote attacker to cause a denial-of-service condition. Recovery requires a system reset.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of MELSEC series CPU modules and MELIPC Series Industrial Computers are affected:
- MELSEC iQ-R Series R00/01/02CPU: Firmware Versions 24 and prior
- MELSEC iQ-R Series R04/08/16/32/120(EN)CPU: Firmware Versions 57 and prior
- MELSEC iQ-R Series R08/16/32/120SFCPU: Firmware Versions 26 and prior
- MELSEC iQ-R Series R08/16/32/120PCPU: Firmware Versions 29 and prior
- MELSEC iQ-R Series R08/16/32/120PSFCPU: Firmware Versions 08 and prior
- MELSEC iQ-R Series R16/32/64MTCPU: Operating system software Versions 23 and prior
- MELSEC iQ-R Series R12CCPU-V: Firmware Versions 16 and prior
- MELSEC Q Series Q03UDECPU, Q04/06/10/13/20/26/50/100UDEHCPU: The first 5 digits of serial No. 23121 and prior
- MELSEC Q Series Q03/04/06/13/26UDVCPU: The first 5 digits of serial No. 23071 and prior
- MELSEC Q Series Q04/06/13/26UDPVCPU: The first 5 digits of serial No. 23071 and prior
- MELSEC Q Series Q12DCCPU-V, Q24DHCCPU-V(G), Q24/26DHCCPU-LS: The first 5 digits of serial No. 24031 and prior
- MELSEC Q Series MR-MQ100: Operating system software version F and prior
- MELSEC Q Series Q172/173DCPU-S1: Operating system software version W and prior
- MELSEC Q Series Q172/173DSCPU: Operating system software version Y and prior
- MELSEC Q Series Q170MCPU: Operating system software version W and prior
- MELSEC Q Series Q170MSCPU(-S1): Operating system software version Y and prior
- MELSEC L Series L02/06/26CPU(-P), L26CPU-(P)BT: The first 5 digits of serial No. 23121 and prior
- MELIPC Series MI5122-VW: Firmware Versions 05 and prior
3.2 Vulnerability Overview
3.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400
The product does not properly control the allocation and maintenance of a limited resource, and could thereby enable an actor to influence resource consumption, eventually leading to the exhaustion of available resources.
CVE-2021-20609 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
3.2.2 IMPROPER HANDLING OF LENGTH PARAMETER INCONSISTENCY CWE-130
The product parses a formatted message or structure, but does not handle or incorrectly handles a length field inconsistent with the actual length of the associated data.
CVE-2021-20610 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
3.2.3 IMPROPER INPUT VALIDATION CWE-20
The product receives input or data, but does not validate or incorrectly validates that the input has the properties required to process the data safely and correctly.
CVE-2021-20611 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
3.3 BACKGROUND
- CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Japan
3.4 RESEARCHER
Mitsubishi Electric reported these vulnerabilities to CISA.
4. MITIGATIONS
Mitsubishi Electric corrected the vulnerabilities in the following products and intends to do the same with other products.
- MELSEC iQ-R Series R00/01/02CPU: Firmware Versions 25 or later
- MELSEC iQ-R Series R04/08/16/32/120(EN)CPU: Firmware Versions 58 or later
- MELSEC iQ-R Series R08/16/32/120SFCPU: Firmware Versions 27 or later
- MELSEC iQ-R Series R08/16/32/120PCPU: Firmware Versions 30 or later
- MELSEC iQ-R Series R08/16/32/120PSFCPU: Firmware Versions 09 or later
- MELSEC iQ-R Series R16/32/64MTCPU: Operating system software Version 24 or later
- MELSEC iQ-R Series R12CCPU-V: Firmware Versions 17 or later
- MELSEC Q Series Q03UDECPU, Q04/06/10/13/20/26/50/100UDEHCPU: The first 5 digits of serial No. 23122 or later
- MELSEC Q Series Q03/04/06/13/26UDVCPU: The first 5 digits of serial No. 23072 or later
- MELSEC Q Series Q04/06/13/26UDPVCPU: The first 5 digits of serial No. 23072 or later
- MELSEC Q Series Q12DCCPU-V, Q24DHCCPU-V(G), Q24/26DHCCPU-LS: The first 5 digits of serial No. 24032 or later
- MELSEC Q Series MR-MQ100: Operating system software version G or later
- MELSEC Q Series Q172/173DCPU-S1: Operating system software version X or later
- MELSEC Q Series Q172/173DSCPU: Operating system software version Z or later
- MELSEC Q Series Q170MCPU: Operating system software version X or later
- MELSEC Q Series Q170MSCPU(-S1): Operating system software version Z or later
- MELSEC L Series L02/06/26CPU(-P), L26CPU-(P)BT: The first 5 digits of serial No. 23122 or later
- MELIPC Series MI5122-VW: Firmware Versions 06 or later
Mitsubishi Electric recommends users take the following mitigation measures to minimize the risk of an attacker exploiting these vulnerabilities:
- Use a firewall or virtual private network (VPN), etc. to prevent unauthorized access when Internet access is required.
- Use a LAN and block access from untrusted networks and hosts through firewalls.
- Use the remote password function or IP filter function to block access from untrusted hosts. For details on the remote password function and IP filter function, please refer to the following manual for each product.
- MELSEC iQ-R Ethernet User’s Manual (Application) 1.13 Security “Remote password” “IP filter”
- MELSEC iQ-R Motion Controller Programming Manual (Common) 6.2 Security Function “IP filter”
- MELSEC iQ-R C Controller Module User’s Manual (Application) 6.6 Security Function “IP filter”
- QnUCPU User’s Manual (Communication via Built-in Ethernet Port) CHAPTER 10 REMOTE PASSWORD
- MELSEC-L CPU Module User’s Manual (Built-In Ethernet Function) CHAPTER 11 REMOTE PASSWORD
- MELIPC MI5000 Series User’s Manual (Application) 11.3 IP Filter Function
For specific update instructions and additional details, see the [Mitsubishi Electric advisory].(https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-019_en.pdf).
CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Specifically, users should:
- Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the Internet.
- Locate control system networks and remote devices behind firewalls and isolate them from business networks.
- 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 at cisa.gov/ics. Several CISA products detailing cyber defense best 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 at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.
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