CVE-2021-37190 is an information disclosure vulnerability identified in Siemens SINEMA Remote Connect Server versions prior to 3.0 SP2. The vulnerability is classified under CWE-200, which pertains to the exposure of sensitive information to unauthorized actors. Specifically, this flaw allows an attacker to retrieve VPN connection details associated with a known user without requiring authentication or user interaction. The vulnerability has a CVSS v3.1 base score of 4.3, indicating a medium severity level. The attack vector is adjacent network (AV:A), meaning the attacker must have access to the same or a logically adjacent network segment as the vulnerable server. The attack complexity is low (AC:L), and no privileges (PR:N) or user interaction (UI:N) are required to exploit this vulnerability. The impact is limited to confidentiality (C:L), with no impact on integrity or availability. SINEMA Remote Connect Server is used primarily in industrial environments to provide secure remote access to industrial control systems (ICS) and operational technology (OT) networks via VPN connections. The exposure of VPN connection details could enable attackers to gain insights into the network topology, user credentials, or VPN configurations, potentially facilitating further targeted attacks or lateral movement within critical infrastructure networks. No known exploits in the wild have been reported, and Siemens has not provided specific patch links in the provided data, though the vulnerability is addressed in version 3.0 SP2 and later. Given the nature of the product and its deployment in critical infrastructure sectors, this vulnerability represents a moderate risk that requires timely remediation to prevent information leakage that could aid attackers in reconnaissance and subsequent exploitation phases.

For European organizations, particularly those operating in critical infrastructure sectors such as energy, manufacturing, transportation, and utilities, this vulnerability poses a risk of sensitive information leakage that could undermine network security. Exposure of VPN connection details may allow adversaries to map network access points, identify privileged users, or gather configuration data that can be leveraged to bypass security controls or escalate attacks. This is especially concerning for industrial control systems where remote access is tightly controlled and where compromise can lead to operational disruptions or safety hazards. Although the vulnerability does not directly impact system integrity or availability, the confidentiality breach can serve as a stepping stone for more severe attacks. European organizations relying on Siemens SINEMA Remote Connect Server for secure remote access should consider this vulnerability a moderate threat that could facilitate espionage, sabotage, or cyber-physical attacks if exploited in conjunction with other vulnerabilities or attack vectors.

1. Upgrade SINEMA Remote Connect Server to version 3.0 SP2 or later, where this vulnerability has been addressed. 2. Restrict network access to the SINEMA Remote Connect Server by implementing strict network segmentation and firewall rules to limit access only to trusted and necessary adjacent network segments. 3. Monitor network traffic for unusual or unauthorized attempts to access VPN connection information, employing intrusion detection systems (IDS) or security information and event management (SIEM) solutions tailored for ICS/OT environments. 4. Implement strong authentication and authorization controls for VPN users and administrators to reduce the risk of credential compromise. 5. Conduct regular security audits and vulnerability assessments focused on remote access infrastructure to identify and remediate similar information disclosure issues. 6. Educate operational technology personnel about the risks associated with information disclosure vulnerabilities and the importance of timely patching and network hygiene. 7. If immediate patching is not feasible, consider deploying compensating controls such as VPN connection logging and alerting, and isolating the SINEMA Remote Connect Server from less secure network zones.