CVE-2021-20587 in FA Engineering Software
Summary
by MITRE • 02/20/2021
Heap-based buffer overflow vulnerability in Mitsubishi Electric FA Engineering Software (C Controller module setting and monitoring tool all versions, CPU Module Logging Configuration Tool all versions, CW Configurator all versions, Data Transfer all versions, EZSocket all versions, FR Configurator all versions, FR Configurator SW3 all versions, FR Configurator2 all versions, GT Designer3 Version1(GOT1000) all versions, GT Designer3 Version1(GOT2000) all versions, GT SoftGOT1000 Version3 all versions, GT SoftGOT2000 Version1 all versions, GX Configurator-DP version 7.14Q and prior, GX Configurator-QP all versions, GX Developer all versions, GX Explorer all versions, GX IEC Developer all versions, GX LogViewer all versions, GX RemoteService-I all versions, GX Works2 version 1.597X and prior, GX Works3 version 1.070Y and prior, M_CommDTM-HART all versions, M_CommDTM-IO-Link all versions, MELFA-Works all versions, MELSEC WinCPU Setting Utility all versions, MELSOFT EM Software Development Kit (EM Configurator) all versions, MELSOFT Navigator all versions, MH11 SettingTool Version2 all versions, MI Configurator all versions, MT Works2 all versions, MX Component all versions, Network Interface Board CC IE Control utility all versions, Network Interface Board CC IE Field Utility all versions, Network Interface Board CC-Link Ver.2 Utility all versions, Network Interface Board MNETH utility all versions, PX Developer all versions, RT ToolBox2 all versions, RT ToolBox3 all versions, Setting/monitoring tools for the C Controller module all versions and SLMP Data Collector all versions) allows a remote unauthenticated attacker to cause a DoS condition of the software products, and possibly to execute a malicious program on the personal computer running the software products although it has not been reproduced, by spoofing MELSEC, GOT or FREQROL and returning crafted reply packets.
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Analysis
by VulDB Data Team • 06/13/2025
This heap-based buffer overflow vulnerability exists within Mitsubishi Electric's comprehensive suite of factory automation engineering software tools, affecting numerous products including C Controller modules, CPU logging configurations, GT Designer3 versions, GX Works2 and GX Works3 environments, and various communication utilities. The vulnerability stems from improper input validation in the handling of network communication protocols, specifically when processing reply packets from devices such as MELSEC, GOT, or FREQROL systems. The flaw allows an attacker to craft malicious packets that, when processed by the vulnerable software, can trigger memory corruption in heap-allocated buffers. This represents a critical security weakness that falls under the CWE-121 heap-based buffer overflow category, where insufficient bounds checking permits memory writes beyond allocated buffer boundaries.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it potentially enables arbitrary code execution on the affected system. Attackers can exploit this weakness by spoofing legitimate industrial communication devices and sending crafted network responses that trigger the buffer overflow during packet processing. The vulnerability affects a broad range of Mitsubishi automation software products, making it particularly dangerous in industrial environments where these tools are commonly used for system configuration, monitoring, and development. Given the nature of industrial control systems, this could result in significant operational disruptions, data integrity compromises, and potential safety hazards in manufacturing environments. The attack vector requires no authentication and can be executed remotely, aligning with ATT&CK technique T1190 for exploit public-facing application and T1059 for command and scripting interpreter.
Mitigation strategies for this vulnerability must address both immediate protection and long-term security posture improvements. Organizations should prioritize applying vendor patches and updates as soon as they become available, since Mitsubishi Electric has released fixes for this specific vulnerability. Network segmentation and access controls should be implemented to limit exposure of these engineering tools to untrusted networks, particularly in industrial environments where direct network access may be unnecessary. The implementation of network monitoring solutions capable of detecting anomalous packet patterns and spoofing attempts can provide early warning capabilities. Additionally, organizations should consider disabling unnecessary network communication features within the affected software, implementing strict input validation controls, and conducting regular security assessments of industrial control system environments. System hardening measures including disabling unused protocols, implementing network access control lists, and maintaining current antivirus signatures should be deployed to reduce the attack surface and mitigate potential exploitation attempts.