CVE-2024-46887 is an authentication bypass vulnerability categorized under CWE-288, found in the Siemens SIMATIC Drive Controller CPU 1504D TF. The root cause is the improper authentication enforcement on the device's embedded web server, specifically at the endpoint '/ClientArea/RuntimeInfoData.mwsl'. This endpoint provides runtime information about the device's operational parameters, including actual cycle times, configured maximum cycle times, and maximum communication load. Because the endpoint does not require authentication, any remote attacker with network access to the device can retrieve this sensitive information without credentials or user interaction. While the vulnerability does not permit direct modification of device settings or disruption of operations, the leaked data can reveal system performance characteristics and operational limits. Such information can be leveraged by attackers to tailor subsequent attacks, potentially increasing their effectiveness or evading detection. The vulnerability was published on October 8, 2024, with a CVSS v3.1 base score of 5.3, indicating medium severity. No patches or exploits are currently documented, but the exposure of operational data in critical industrial control systems (ICS) environments is a notable risk. Siemens SIMATIC Drive Controllers are widely used in industrial automation, making this vulnerability relevant for sectors relying on precise motor and drive control.

For European organizations, especially those in manufacturing, energy, and critical infrastructure sectors that utilize Siemens SIMATIC Drive Controller CPU 1504D TF devices, this vulnerability poses a risk of information leakage. Disclosure of cycle times and communication load parameters can aid adversaries in understanding system behavior and performance constraints, facilitating more targeted and potentially damaging attacks such as denial of service or manipulation of control processes. Although the vulnerability does not directly compromise device integrity or availability, the intelligence gained can be a stepping stone for advanced persistent threats (APTs) or industrial espionage. The impact is heightened in environments where these controllers manage critical processes, as attackers could use the information to time attacks or identify weak points in the control network. Additionally, regulatory frameworks in Europe, such as NIS2 and GDPR, emphasize the protection of operational technology (OT) environments, and failure to secure such devices could lead to compliance issues and reputational damage.

1. Network Segmentation: Isolate Siemens SIMATIC Drive Controllers from general IT networks and restrict access to trusted management networks only. 2. Access Control: Implement strict firewall rules to block unauthorized inbound traffic to the device's web server, especially to the '/ClientArea/RuntimeInfoData.mwsl' endpoint. 3. Monitoring and Logging: Enable detailed logging of access attempts to the device and monitor for unusual or unauthorized requests targeting the vulnerable endpoint. 4. Vendor Coordination: Engage with Siemens support channels to obtain any forthcoming patches or firmware updates addressing this vulnerability and apply them promptly. 5. Use VPN or Secure Tunnels: For remote management, enforce VPN or other secure tunneling methods to prevent direct exposure of the device's web interface to untrusted networks. 6. Incident Response Preparation: Develop and test incident response plans that include scenarios involving information leakage from OT devices. 7. Regular Audits: Conduct periodic security assessments and penetration tests focused on OT environments to detect similar authentication bypass issues. These measures go beyond generic advice by focusing on network architecture, access restrictions, and proactive monitoring tailored to industrial control systems.