CVE-2022-46144 is a vulnerability identified in multiple Siemens SCALANCE industrial network devices, specifically models SC622-2C, SC626-2C, SC632-2C, SC636-2C, SC642-2C, SC646-2C, WAM763-1, WAM766-1 (including US and EEC variants), and WUM763-1, WUM766-1 (including USA variants). These devices are widely used in industrial control systems (ICS) and critical infrastructure networks for secure communication and network segmentation. The vulnerability arises from improper control of a resource through its lifetime (CWE-664). Specifically, the affected devices do not correctly handle command-line interface (CLI) commands after a user forcefully terminates an SSH session. This improper resource management can cause the CLI accessed via SSH or serial interface to become unresponsive. The issue affects all firmware versions prior to V2.3 or V3.0 depending on the device model, and for some wireless models, all versions prior to V2.0.0. Exploitation requires an authenticated attacker with access to the device's CLI via SSH or serial interface. Although no public exploits are currently known, successful exploitation could disrupt device management and network operations by rendering the CLI unresponsive, potentially impacting the availability and maintainability of critical network infrastructure. Siemens has not yet published patches or mitigations at the time of this report. The vulnerability was published on December 13, 2022, and is classified under CWE-664, indicating a failure to properly manage resource lifetimes leading to potential denial of service conditions.

For European organizations, especially those operating critical infrastructure such as energy grids, manufacturing plants, transportation networks, and utilities, this vulnerability poses a significant risk to operational continuity. Siemens SCALANCE devices are commonly deployed in industrial environments across Europe for secure and reliable network communication. An attacker with authenticated access could exploit this vulnerability to cause denial of service by making the CLI unresponsive, thereby preventing administrators from managing or troubleshooting the affected devices. This could delay incident response, complicate network reconfiguration, and potentially lead to extended downtime or degraded network segmentation, increasing exposure to further attacks. The impact on confidentiality and integrity is limited as exploitation requires authentication and does not directly enable data exfiltration or manipulation. However, the availability impact is notable, as loss of CLI access can hinder operational control and recovery efforts. Given the critical role of these devices in industrial networks, even temporary disruptions can have cascading effects on production processes and safety systems. The lack of known exploits reduces immediate risk, but the vulnerability remains a concern for organizations with Siemens SCALANCE devices in their operational technology (OT) environments.

1. Immediate mitigation should focus on restricting authenticated access to the affected devices. Implement strict access controls, including multi-factor authentication and network segmentation, to limit CLI access to trusted personnel only. 2. Monitor SSH session terminations and CLI responsiveness closely to detect abnormal behavior indicative of exploitation attempts. 3. Where possible, avoid forcefully terminating SSH sessions; instead, use proper session closure procedures to prevent triggering the vulnerability. 4. Maintain up-to-date backups of device configurations to enable rapid recovery if CLI access is lost. 5. Engage with Siemens support channels to obtain official patches or firmware updates as they become available and prioritize their deployment. 6. Consider deploying network-level protections such as intrusion detection systems (IDS) tuned to detect anomalous SSH session behaviors targeting SCALANCE devices. 7. Conduct regular security audits and penetration testing focused on OT network devices to identify and remediate similar resource management issues proactively. 8. Document and train operational staff on incident response procedures specific to loss of CLI access to minimize downtime during exploitation scenarios.