CVE-2022-46355 is a high-severity vulnerability affecting multiple versions of Siemens SCALANCE X204RNA industrial networking devices, specifically all versions prior to V3.2.7. The affected models include SCALANCE X204RNA (HSR), SCALANCE X204RNA (PRP), SCALANCE X204RNA EEC (HSR), SCALANCE X204RNA EEC (PRP), and SCALANCE X204RNA EEC (PRP/HSR). These devices are used in industrial automation and critical infrastructure environments to provide highly reliable Ethernet communication via High-availability Seamless Redundancy (HSR) and Parallel Redundancy Protocol (PRP). The vulnerability is classified under CWE-200, indicating an exposure of sensitive information to unauthorized actors. Specifically, the issue arises from the leakage of sensitive data through the HTTP Referer header. This means that when the device’s web interface or HTTP services are accessed, sensitive information may be inadvertently included in the Referer header sent to third parties or logged in places accessible to unauthorized users. The CVSS 3.1 base score of 7.5 reflects a high severity, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The impact is limited to confidentiality (C:H), with no impact on integrity or availability. No known exploits are reported in the wild as of the publication date. The vulnerability does not require authentication or user interaction, making it easier to exploit remotely by an attacker who can intercept or observe HTTP traffic or logs containing the Referer header. Since these devices are often deployed in industrial control systems (ICS) and critical infrastructure, exposure of sensitive information could aid attackers in reconnaissance or further exploitation steps.

For European organizations, especially those operating in industrial sectors such as manufacturing, energy, transportation, and utilities, this vulnerability poses a significant risk. Siemens SCALANCE X204RNA devices are widely used in European industrial environments due to Siemens’ strong market presence. Exposure of sensitive information could include network topology details, configuration parameters, or operational data that attackers can leverage to plan targeted attacks or disrupt industrial processes. Although the vulnerability does not directly impact system integrity or availability, the confidentiality breach can facilitate lateral movement, targeted intrusion, or espionage activities. This is particularly critical for organizations involved in critical infrastructure where industrial network security is paramount. The lack of required authentication and user interaction increases the risk of remote exploitation by malicious actors, including cybercriminals or state-sponsored groups. The vulnerability could also undermine compliance with European data protection regulations if sensitive operational data is exposed. Overall, the impact is primarily on confidentiality but with potentially severe downstream consequences for operational security and industrial resilience.

1. Immediate upgrade of all affected SCALANCE X204RNA devices to firmware version 3.2.7 or later, where the vulnerability is patched, is the most effective mitigation. 2. Implement network segmentation and strict access controls to limit exposure of device management interfaces to trusted internal networks only. Avoid exposing these devices or their web interfaces to the public internet or untrusted networks. 3. Deploy network monitoring and intrusion detection systems capable of detecting unusual HTTP traffic patterns or unauthorized access attempts to industrial network devices. 4. Use encrypted communication channels (e.g., HTTPS with strong TLS configurations) to minimize the risk of HTTP header interception and leakage. 5. Review and sanitize HTTP Referer headers in proxy or gateway devices where possible to prevent sensitive information leakage. 6. Conduct regular security audits and vulnerability assessments of industrial network devices to identify and remediate similar information exposure issues proactively. 7. Establish incident response plans specific to industrial control system environments to quickly address potential exploitation attempts. These mitigations go beyond generic advice by focusing on industrial network-specific controls, firmware management, and HTTP header handling.