Mitsubishi Electric MELSEC iQ-F Series (Update B)

1. EXECUTIVE SUMMARY

• CVSS v3 8.6
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Mitsubishi Electric
• Equipment: MELSEC iQ-F Series
• Vulnerabilities: Improper Input Validation

2. UPDATE INFORMATION

This updated advisory is a follow-up to the original advisory titled ICSA-22-139-01 Mitsubishi Electric MELSEC iQ-F Series that was published May 19, 2022, on the ICS webpage at cisa.gov/ics. 

3. RISK EVALUATION

Successful exploitation of these vulnerabilities could cause a denial-of-service condition by sending specially crafted packets. A system reset is required for recovery.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

The following versions of the MELSEC iQ-F series a CPU module are affected:

• MELSEC iQ-F FX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS with serial number 17X**** or later: All versions prior to 1.270
• MELSEC iQ-F FX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS with Serial number 179**** and prior: All versions prior to 1.073
• MELSEC iQ-F FX5UC-xMy/z x=32,64,96, y=T,R, z=D,DSS with serial number 17X**** or later: All versions prior to 1.270
• MELSEC iQ-F FX5UC-xMy/z x=32,64,96, y=T,R, z=D,DSS with Serial number 179**** and prior: All versions prior to 1.073
• MELSEC iQ-F FX5UC-32MT/DS-TS, FX5UC-32MT/DSS-TS, FX5UC-32MR/DS-TS: All versions prior to 1.270
• MELSEC iQ-F FX5UJ-xMy/z x=24,40,60, y=T,R, z=ES,ESS: All versions prior to 1.030
• MELSEC iQ-F FX5UJ-xMy/ES-A x=24,40,60, y=T.R: All versions prior to 1.031 (These products are sold in limited regions)

--------- Begin Update B part 1 of 2 ---------

• MELSEC iQ-F FX5S-xMy/z x=30,40,60,80, y=T.R, z=ES,ESS: Version 1.000 

--------- End Update B part 1 of 2 ---------

4.2 VULNERABILITY OVERVIEW

4.2.1    IMPROPER INPUT VALIDATION CWE-20

The affected product is vulnerable to a specially crafted packet, which may allow an attacker to cause a denial-of-service condition where a system reset is required for recovery.

CVE-2022-25161 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).

4.2.2    IMPROPER INPUT VALIDATION CWE-20

The affected product is vulnerable to a specially crafted packet, which may allow an attacker to cause a denial-of-service condition.

CVE-2022-25162 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

4.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Japan

4.4 RESEARCHER

Anton Dorfman of Positive Technologies reported these vulnerabilities to Mitsubishi Electric.

5. MITIGATIONS

Mitsubishi Electric has provided the following mitigations or workarounds: 

• MELSEC iQ-F FX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS with Serial number 17X**** or later update to v1.270 or later
• MELSEC iQ-F FX5U-xMy/z x=32,64,80, y=T,R, z=ES, DS, ESS, DSS with serial number 179**** and prior update to v1.073 or later
• MELSEC iQ-F FX5UC-xMy/z x=32,64,96, y=T,R, z=D,DSS with serial number 17X**** or later update to v1.270 or later
• MELSEC iQ-F FX5UC-xMy/z x=32,64,96, y=T,R, z=D,DSS with Serial number 179**** and prior update to v1.073 or later
• MELSEC iQ-F FX5UC-32MT/DS-TS, FX5UC-32MT/DSS-TS, FX5UC-32MR/DS-TS update to v1.270 or later
• MELSEC iQ-F FX5UJ-xMy/z x=24,40,60, y=T,R, z=ES,ESS update to v1.030 or later
• MELSEC iQ-F FX5UJ-xMy/ES-A x=24,40,60, y=T.R please contact a Mitsubishi Electric representative

--------- Begin Update B Part 2 of 2 ---------

• MELSEC iQ-F FX5S-xMy/z x-30,40,60,80, y=T.R, z=ES,ESS update to v1.001 or later 

--------- End Update B Part 2 of 2 ---------

Use a firewall or virtual private network to prevent unauthorized access when Internet access is required.

Use firewalls or an IP filter function to restrict connections to these products and prevent access from untrusted networks or hosts. For details on the IP filter function, refer to 12.1 IP Filter Function in MELSEC iQ-F FX5 User’s Manual (Ethernet Communication).

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 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 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 these vulnerabilities.