CVE-2025-9279 is a vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) affecting Rockwell Automation's ArmorStart® LT product, specifically versions V2.002 and below. The vulnerability manifests during the execution of Achilles EtherNet/IP Step Limit Storm tests, which are designed to stress-test EtherNet/IP devices. When these tests are run against vulnerable ArmorStart® LT devices, the system experiences unexpected reboots. This reboot causes the Link State Monitor—a critical component responsible for monitoring network link status—to go down temporarily for several seconds, resulting in a denial-of-service (DoS) condition. The vulnerability is remotely exploitable without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The CVSS v4.0 base score is 8.7, reflecting a high severity due to the potential for significant operational disruption in industrial environments. The root cause is uncontrolled resource consumption triggered by the test traffic, which overwhelms the device's capacity to maintain stable operation. No patches or exploit code are currently publicly available, but the vulnerability has been officially published and reserved since August 2025. Given the critical role of ArmorStart® LT in industrial automation and network monitoring, this vulnerability poses a risk to the availability and reliability of industrial control systems (ICS) and operational technology (OT) networks.

The primary impact of CVE-2025-9279 is denial-of-service caused by unexpected device reboots and temporary loss of the Link State Monitor functionality. For European organizations, especially those in manufacturing, energy, transportation, and critical infrastructure sectors that rely on Rockwell Automation's ArmorStart® LT for network monitoring and control, this can lead to operational disruptions, production downtime, and potential safety risks. The temporary loss of link state monitoring may delay detection of network issues or failures, increasing the risk of cascading failures in industrial processes. Additionally, the vulnerability can be exploited remotely without authentication, increasing the attack surface. Although no known exploits are currently in the wild, the high CVSS score indicates that attackers could leverage this vulnerability to disrupt industrial operations, potentially causing financial losses and impacting supply chains. The impact is heightened in environments where continuous network availability and real-time monitoring are critical for safety and compliance with regulatory standards.

1. Upgrade ArmorStart® LT devices to versions above V2.002 once Rockwell Automation releases a patch or updated firmware addressing CVE-2025-9279. 2. Until patches are available, implement strict network segmentation to isolate ArmorStart® LT devices from untrusted or test traffic sources, especially those performing EtherNet/IP stress tests like Achilles. 3. Deploy intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection capabilities tuned to identify and block EtherNet/IP Step Limit Storm test traffic patterns. 4. Restrict access to network management and testing tools to authorized personnel only, enforcing strong access controls and monitoring. 5. Conduct regular network traffic analysis to detect unusual spikes or patterns indicative of resource exhaustion attempts. 6. Develop and test incident response plans that include procedures for rapid recovery from device reboots and monitoring outages. 7. Collaborate with Rockwell Automation support for guidance and early access to patches or mitigation advisories. 8. Consider redundant monitoring systems to maintain visibility during potential outages caused by this vulnerability.