CVE-2025-13824 is a vulnerability classified under CWE-763 (Release of Invalid Pointer or Reference) found in Rockwell Automation's Micro820®, Micro850®, and Micro870® programmable logic controllers (PLCs). The issue stems from improper processing of malformed CIP packets during fuzzing, which causes the controller firmware to dereference invalid pointers or references. This leads the device to enter a hard fault state, indicated by a solid red Fault LED, rendering the controller unresponsive and effectively causing a denial of service. Upon power cycling, the device transitions to a recoverable fault state, flashing the MS and Fault LEDs red and reporting fault code 0xF019. Recovery requires manual intervention to clear the fault. The vulnerability is remotely exploitable without authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The CVSS score of 8.7 reflects the high impact on availability, with no confidentiality or integrity impact. The affected firmware versions include V23.011 and below for Micro820®, V12.013 and lower for Micro850®, and V14.011 and lower for Micro870®. No patches or exploits are currently publicly available, but the vulnerability poses a significant risk to industrial environments relying on these controllers for automation and control.

For European organizations, especially those operating in critical infrastructure sectors such as manufacturing, energy, water treatment, and transportation, this vulnerability poses a significant risk of operational disruption. The affected Rockwell Automation Micro series controllers are widely used in industrial automation across Europe. Exploitation could lead to denial of service conditions, halting production lines or critical processes, potentially causing financial losses, safety hazards, and regulatory non-compliance. The lack of confidentiality or integrity impact reduces risks related to data breaches but does not diminish the threat to availability and operational continuity. Given the remote exploitability without authentication, attackers could disrupt operations from outside the network perimeter if proper network segmentation and protections are not in place. This is particularly concerning for European organizations with legacy or unpatched industrial control systems (ICS) that may not have robust security monitoring or incident response capabilities.

1. Immediate assessment and inventory of all Rockwell Automation Micro820®, Micro850®, and Micro870® controllers to identify affected firmware versions. 2. Apply vendor-provided patches or firmware updates as soon as they become available; monitor Rockwell Automation advisories closely. 3. Implement strict network segmentation to isolate ICS networks from corporate and external networks, limiting exposure to potentially malicious CIP packets. 4. Deploy intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection tuned for CIP protocol traffic to detect malformed packets. 5. Restrict network access to controllers using firewalls and access control lists (ACLs), allowing only trusted management stations and devices. 6. Establish monitoring and alerting for fault LED indicators and fault codes on controllers to enable rapid detection of exploitation attempts or faults. 7. Develop and test incident response procedures for controller faults and recovery, including automated fault clearing if supported. 8. Conduct regular security audits and penetration testing focused on ICS environments to identify and remediate similar vulnerabilities proactively.