CVE-2022-46352 is a high-severity vulnerability affecting multiple versions of Siemens SCALANCE X204RNA devices, specifically those versions prior to V3.2.7. These devices include SCALANCE X204RNA (HSR), SCALANCE X204RNA (PRP), and their EEC variants supporting HSR and PRP protocols. The vulnerability is classified under CWE-400, which pertains to uncontrolled resource consumption. The issue arises when specially crafted PROFINET DCP (Discovery and Configuration Protocol) packets are sent to the affected devices. These malformed packets can trigger a denial of service (DoS) condition by exhausting device resources, leading to unavailability or degraded performance of the network switch. The vulnerability requires no authentication or user interaction and can be exploited remotely over the network (AV:N, AC:L, PR:N, UI:N). The impact is limited to availability (A:H), with no direct confidentiality or integrity compromise. Siemens has addressed this vulnerability in firmware version 3.2.7 and later. No known exploits have been reported in the wild as of the publication date, December 13, 2022. The SCALANCE X204RNA series is widely used in industrial automation environments, particularly in critical infrastructure and manufacturing sectors, where High-availability Seamless Redundancy (HSR) and Parallel Redundancy Protocol (PRP) are employed to ensure network reliability and fault tolerance. An attacker exploiting this vulnerability could disrupt industrial communication networks by causing device outages, potentially halting production lines or critical processes dependent on these switches.

For European organizations, the impact of CVE-2022-46352 could be significant, especially in sectors relying heavily on industrial automation and critical infrastructure, such as manufacturing, energy, transportation, and utilities. The affected SCALANCE X204RNA devices are integral components in industrial Ethernet networks that require high availability and redundancy. A successful denial of service attack could lead to network outages, interrupting real-time communication between control systems and field devices. This disruption could cause production downtime, safety risks, and financial losses. Given the vulnerability does not affect confidentiality or integrity, the primary concern is operational availability. Moreover, since the exploit requires no authentication and no user interaction, attackers with network access—potentially including insiders or attackers who have breached perimeter defenses—could trigger the DoS condition. The lack of known exploits in the wild suggests limited immediate risk, but the critical role of these devices in industrial environments means that exploitation could have cascading effects on European industrial operations and supply chains.

1. Immediate firmware upgrade: Organizations should prioritize updating all affected SCALANCE X204RNA devices to firmware version 3.2.7 or later, which contains the patch for this vulnerability. 2. Network segmentation: Isolate industrial control system (ICS) networks from corporate and external networks to reduce exposure. Limit access to PROFINET DCP traffic to trusted devices only. 3. Traffic filtering: Implement deep packet inspection or protocol-aware firewalls to detect and block malformed or suspicious PROFINET DCP packets at network boundaries. 4. Monitoring and anomaly detection: Deploy network monitoring tools capable of recognizing unusual PROFINET DCP traffic patterns or spikes in resource consumption on SCALANCE devices. 5. Access control: Restrict network access to SCALANCE devices to authorized personnel and systems, employing strong network access controls and authentication mechanisms where possible. 6. Incident response readiness: Prepare for potential DoS incidents by establishing response procedures, including rapid device reboot or failover strategies to maintain network availability. 7. Vendor coordination: Maintain communication with Siemens for updates, advisories, and support related to SCALANCE devices and related vulnerabilities.