CVE-2025-9368 Overview
CVE-2025-9368 is a denial-of-service vulnerability affecting the Rockwell Automation 432ES-IG3 Series A GuardLink® EtherNet/IP Interface. A network-based attacker can trigger a condition that renders the device unresponsive. Recovery requires a manual power cycle, meaning operators must physically intervene to restore service. The flaw is categorized under CWE-770, Allocation of Resources Without Limits or Throttling. The vulnerability impacts availability only and does not affect confidentiality or integrity of data processed by the device.
Critical Impact
Remote, unauthenticated attackers can knock the GuardLink EtherNet/IP Interface offline. The device remains down until staff manually cycle power, disrupting safety-related industrial control operations.
Affected Products
- Rockwell Automation 432ES-IG3 Series A
- GuardLink® EtherNet/IP Interface module
- Industrial control deployments relying on the affected interface for safety signaling
Discovery Timeline
- 2025-12-09 - CVE-2025-9368 published to NVD
- 2026-04-15 - Last updated in NVD database
Technical Details for CVE-2025-9368
Vulnerability Analysis
The vulnerability resides in the GuardLink® EtherNet/IP Interface firmware running on the 432ES-IG3 Series A. Crafted network traffic directed at the interface causes the device to enter an unrecoverable state. Normal protocol handling logic fails to bound the resources consumed during request processing. Once exhausted, the device stops responding to EtherNet/IP traffic and safety-link operations. Unlike a transient stall, the condition persists until power is removed and reapplied, indicating watchdog and software-level recovery mechanisms do not engage.
The device's role in industrial safety chains amplifies the operational impact. A downed GuardLink interface can interrupt safety signaling between guard locks, light curtains, and controllers, forcing protective shutdowns on connected machinery. Refer to the Rockwell Automation Security Advisory SD1764 for vendor-confirmed technical specifics.
Root Cause
The root cause maps to CWE-770: the interface allocates resources to handle incoming network requests without enforcing throttling or upper bounds. An attacker who reaches the device on the network can exhaust those resources and leave the firmware unable to service legitimate traffic.
Attack Vector
Exploitation requires only network reachability to the affected interface. The attacker needs no credentials and no user interaction. A single attacker-controlled host on the operational technology (OT) network, or any pivot point with routing to the device, is sufficient to trigger the denial-of-service condition.
No public proof-of-concept code is available. See the Rockwell Automation advisory for vendor guidance.
Detection Methods for CVE-2025-9368
Indicators of Compromise
- Sudden loss of EtherNet/IP communication with one or more 432ES-IG3 Series A modules
- Safety controllers reporting GuardLink chain faults without a physical cause
- Devices that remain unresponsive on the network until a manual power cycle restores them
Detection Strategies
- Baseline EtherNet/IP traffic to the GuardLink interface and alert on anomalous source addresses or malformed packet patterns
- Correlate controller-side safety faults with simultaneous EtherNet/IP heartbeat loss to the interface
- Track unscheduled power-cycle events on 432ES-IG3 modules as a signal of post-incident recovery
Monitoring Recommendations
- Forward switch and firewall logs from the OT segment to a centralized analytics platform for cross-source correlation
- Monitor for unauthorized hosts initiating connections to TCP/UDP 44818 and 2222 on the affected subnet
- Alert on repeated connection resets or dropped sessions involving the GuardLink interface
How to Mitigate CVE-2025-9368
Immediate Actions Required
- Restrict network access to the 432ES-IG3 Series A interface to authorized engineering workstations and controllers only
- Place affected devices behind an industrial firewall or inside a dedicated cell/area zone per ISA/IEC 62443
- Review the Rockwell Automation Security Advisory SD1764 and apply vendor-provided remediation when available
Patch Information
Rockwell Automation has issued advisory SD1764 covering CVE-2025-9368. Consult the advisory for firmware updates, fixed versions, and any vendor-recommended configuration changes applicable to the 432ES-IG3 Series A GuardLink® EtherNet/IP Interface.
Workarounds
- Segment the OT network so the GuardLink interface is unreachable from enterprise IT and external networks
- Apply allow-list firewall rules permitting EtherNet/IP traffic only from known controller and engineering IP addresses
- Disable or block remote access paths into the cell/area zone hosting the device until a vendor fix is deployed
- Establish a documented manual recovery procedure so operations staff can quickly power-cycle the device if disruption occurs
# Example firewall allow-list restricting EtherNet/IP access to the GuardLink interface
# Replace addresses with site-specific controller and engineering workstation IPs
iptables -A FORWARD -s 10.20.30.10,10.20.30.11 -d 10.20.30.50 -p tcp --dport 44818 -j ACCEPT
iptables -A FORWARD -s 10.20.30.10,10.20.30.11 -d 10.20.30.50 -p udp --dport 2222 -j ACCEPT
iptables -A FORWARD -d 10.20.30.50 -p tcp --dport 44818 -j DROP
iptables -A FORWARD -d 10.20.30.50 -p udp --dport 2222 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
