CVE-2023-4625 in MELSEC iQ-F
Summary
by MITRE • 11/06/2023
Improper Restriction of Excessive Authentication Attempts vulnerability in Mitsubishi Electric Corporation MELSEC iQ-F Series CPU modules Web server function allows a remote unauthenticated attacker to prevent legitimate users from logging into the Web server function for a certain period after the attacker has attempted to log in illegally by continuously attempting unauthorized login to the Web server function. The impact of this vulnerability will persist while the attacker continues to attempt unauthorized login.
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Analysis
by VulDB Data Team • 11/30/2023
The vulnerability identified as CVE-2023-4625 represents a critical weakness in the Mitsubishi Electric Corporation MELSEC iQ-F Series CPU modules that directly impacts the security posture of industrial control systems. This flaw resides within the web server function of these industrial automation devices, which are widely deployed in manufacturing environments, process control systems, and critical infrastructure applications. The vulnerability manifests as an improper restriction of excessive authentication attempts, creating a pathway for malicious actors to disrupt legitimate system access through deliberate abuse of the authentication mechanism.
The technical nature of this vulnerability stems from the absence of effective rate-limiting and account lockout mechanisms within the web server implementation. When an attacker attempts unauthorized login requests to the web interface, the system fails to adequately monitor or restrict the frequency of these attempts. This allows for continuous brute force or dictionary attack scenarios where the attacker can systematically try multiple credential combinations without triggering protective measures. The flaw specifically affects the authentication process of the web server function, which serves as the primary interface for system configuration, monitoring, and administrative access in these industrial controllers.
The operational impact of this vulnerability extends beyond simple denial of service to potentially compromise the integrity and availability of critical industrial processes. When exploited, the vulnerability enables an attacker to maintain persistent disruption of legitimate user access, effectively locking out authorized personnel from performing necessary system maintenance, configuration changes, or operational monitoring. This disruption can persist for extended periods as long as the attacker continues their unauthorized login attempts, potentially causing production delays, operational inefficiencies, or even safety risks in environments where timely system access is crucial for process control and emergency response procedures.
The vulnerability aligns with CWE-307 which specifically addresses improper restriction of excessive authentication attempts, and demonstrates characteristics consistent with attack patterns documented in the MITRE ATT&CK framework under the credential access and defense evasion domains. This weakness creates opportunities for attackers to perform persistent disruption attacks that can remain undetected while systematically degrading system availability. The impact is particularly concerning in industrial environments where system uptime and reliable access are paramount for operational continuity and safety compliance requirements.
Organizations should implement immediate mitigations including network segmentation to restrict access to these industrial controllers, deployment of intrusion detection systems to monitor for unusual authentication patterns, and implementation of network-level rate limiting for web traffic to the affected devices. Configuration changes should enforce strict authentication policies with account lockout mechanisms, implement strong access controls, and establish monitoring procedures to detect and respond to unauthorized access attempts. Additionally, regular security assessments and vulnerability management processes should be enhanced to identify and remediate similar weaknesses in industrial control system components. The vulnerability underscores the importance of applying security best practices to industrial environments where traditional cybersecurity measures may not be sufficient to protect against sophisticated attack vectors targeting operational technology infrastructure.