CVE-2019-18261 in PLC CS
Summary
by MITRE
In Omron PLC CS series, all versions, Omron PLC CJ series, all versions, and Omron PLC NJ series, all versions, the software does not implement sufficient measures to prevent multiple failed authentication attempts within in a short time frame, making it more susceptible to brute force attacks.
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Analysis
by VulDB Data Team • 03/12/2024
The vulnerability identified as CVE-2019-18261 affects Omron programmable logic controllers across multiple series including CS, CJ, and NJ series across all versions. This weakness represents a critical security flaw in industrial control systems that directly impacts the authentication mechanisms of these devices. The vulnerability stems from the absence of effective rate limiting or account lockout mechanisms within the PLC software implementations, creating an exploitable condition that undermines the fundamental security posture of these industrial devices. Organizations relying on these controllers for critical infrastructure operations face significant risks due to this implementation gap.
The technical flaw manifests as a lack of sufficient protection against repeated authentication attempts that occur within brief time intervals. This absence of protective measures allows attackers to systematically test numerous password combinations without triggering automatic account lockout or temporary access restrictions. The vulnerability directly maps to CWE-307 - "Improper Restriction of Excessive Authentication Attempts" which specifically addresses insufficient mechanisms to prevent automated authentication attacks. The flaw enables adversaries to conduct brute force attacks against the PLC authentication system with minimal risk of detection or account lockout, significantly reducing the time required to compromise authentication credentials.
The operational impact of this vulnerability extends beyond simple credential compromise to potentially enable full system control and disruption of industrial processes. Attackers who successfully exploit this weakness can gain unauthorized access to critical control systems, potentially leading to production disruption, safety hazards, or even physical damage to industrial equipment. The vulnerability is particularly concerning in industrial environments where PLCs control manufacturing processes, power generation, or other critical infrastructure operations. This weakness creates opportunities for attackers to execute malicious code, modify control parameters, or gain persistent access to industrial networks, representing a significant risk to operational technology security. The vulnerability aligns with ATT&CK technique T1110 - "Brute Force" which specifically addresses the use of repeated login attempts to gain unauthorized access to systems.
Mitigation strategies for this vulnerability should focus on implementing robust authentication controls and network segmentation measures. Organizations should deploy network access controls to restrict direct access to PLC devices, implement strong authentication mechanisms with account lockout policies, and establish monitoring for suspicious authentication patterns. Network segmentation can help limit the attack surface by preventing direct access to PLCs from external networks. Additionally, regular security assessments should be conducted to identify and remediate similar authentication weaknesses across industrial control systems. The implementation of multi-factor authentication where possible, along with regular credential rotation and comprehensive network monitoring, provides additional layers of protection against exploitation of this vulnerability.