CVE-2024-36980 is an out-of-bounds read vulnerability classified under CWE-125, discovered in the OpenPLC_v3 Runtime's EtherNet/IP PCCC parser functionality. OpenPLC is an open-source industrial control system platform used to implement programmable logic controllers (PLCs) in various automation environments. The vulnerability arises from an incorrect comparison in the parser code that processes EtherNet/IP PCCC protocol messages, allowing an attacker to read memory outside the intended buffer boundaries. By sending a series of specially crafted EtherNet/IP requests, an unauthenticated remote attacker can trigger this flaw, leading to a denial of service (DoS) condition where the OpenPLC runtime crashes or becomes unresponsive. This vulnerability does not impact confidentiality or integrity directly but severely affects availability, which is critical in industrial control systems. The CVSS v3.1 base score of 7.5 reflects a network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality or integrity impact (C:N/I:N), and high availability impact (A:H). No known public exploits or patches are currently available, making proactive mitigation essential. This is the first identified instance of this specific incorrect comparison leading to an out-of-bounds read in OpenPLC_v3.

The primary impact of CVE-2024-36980 is denial of service, which can cause industrial control systems running OpenPLC_v3 to crash or become unresponsive. For European organizations, especially those operating critical infrastructure such as manufacturing plants, energy grids, water treatment facilities, and transportation systems that utilize OpenPLC for automation, this vulnerability poses a significant operational risk. Disruption of PLC operations can halt production lines, cause safety system failures, or interrupt essential services, potentially leading to economic losses and safety hazards. Since the vulnerability can be exploited remotely without authentication or user interaction, attackers can launch attacks from outside the network perimeter, increasing the threat surface. Although no data confidentiality or integrity is compromised, the loss of availability in industrial environments can have cascading effects on supply chains and public safety. The lack of known exploits in the wild provides a window for mitigation, but the high severity score indicates that exploitation is feasible and impactful.

1. Network Segmentation: Isolate OpenPLC devices and their management interfaces from general enterprise networks and the internet. Use VLANs and firewalls to restrict EtherNet/IP traffic to trusted sources only. 2. Intrusion Detection and Prevention: Deploy network monitoring tools capable of detecting anomalous EtherNet/IP traffic patterns and malformed PCCC requests indicative of exploitation attempts. 3. Access Controls: Restrict access to OpenPLC runtime systems to authorized personnel and systems only, using strong authentication and VPNs for remote access. 4. Patch Management: Monitor OpenPLC project updates closely for patches addressing CVE-2024-36980 and apply them promptly once available. 5. Incident Response Planning: Prepare and test response procedures for potential DoS incidents affecting industrial control systems to minimize downtime. 6. Vendor Engagement: Engage with OpenPLC developers or vendors for guidance, potential workarounds, or interim fixes. 7. Configuration Hardening: Disable or limit EtherNet/IP PCCC parser functionality if not required for operational needs to reduce attack surface. 8. Logging and Forensics: Enable detailed logging on OpenPLC devices to facilitate detection and investigation of suspicious activities related to this vulnerability.