OTPulse
FeedAboutContact

Mitsubishi Electric MELSEC-F Series

Plan Patch7.5ICS-CERT ICSA-22-013-01Jan 13, 2022
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary

The FX3U-ENET, FX3U-ENET-L, and FX3U-ENET-P502 communication modules contain a vulnerability in their network message handling that can be triggered by a specially crafted packet. Exploitation causes a denial-of-service condition that disrupts the module's communication function, preventing data exchange with remote systems. Affected firmware versions are 1.14 and earlier.

What this means
What could happen
A successful attack could disable communication functions on the FX3U-ENET module, preventing the PLC from exchanging data with remote devices or control systems. This could stop remote process monitoring and control until the device recovers or is manually reset.
Who's at risk
Energy sector operators running Mitsubishi Electric MELSEC-F series programmable logic controllers (PLCs) with FX3U-ENET, FX3U-ENET-L, or FX3U-ENET-P502 Ethernet communication modules are affected. This includes power generation, distribution, and water/wastewater treatment facilities that rely on these modules for remote monitoring and control.
How it could be exploited
An attacker with network access to the FX3U-ENET module can send a specially crafted network packet that triggers a denial-of-service condition in the module's communication stack. The attacker does not need credentials or any special privileges—only the ability to reach the module's network interface.
Prerequisites
  • Network access to the FX3U-ENET module's Ethernet port
  • No authentication or special configuration required
remotely exploitableno authentication requiredlow complexity attackno patch available for older firmware versionsaffects process communication
Exploitability
Low exploit probability (EPSS 0.4%)
Affected products (3)
3 with fix
ProductAffected VersionsFix Status
FX3U-ENET Firmware:≤ 1.141.16 or later
FX3U-ENET-L Firmware:≤ 1.141.16 or later
FX3U-ENET-P502 Firmware:≤ 1.141.16 or later
Remediation & Mitigation
0/6
Do now
0/1
WORKAROUNDConfigure firewall rules to restrict network access to FX3U-ENET modules from untrusted networks and hosts
Schedule — requires maintenance window
0/3

Patching may require device reboot — plan for process interruption

HOTFIXUpdate FX3U-ENET firmware to version 1.16 or later
HOTFIXUpdate FX3U-ENET-L firmware to version 1.16 or later
HOTFIXUpdate FX3U-ENET-P502 firmware to version 1.16 or later
Long-term hardening
0/2
HARDENINGDeploy the FX3U-ENET modules on isolated LANs separated from the corporate network and Internet
HARDENINGUse VPN or firewall to control access if Internet connectivity is required
View full CISA ICS-CERT advisory
↑↓ Navigate · Esc Close
API: /api/v1/advisories/76b41a6d-ba89-45da-8307-53453f2ab9bf