CVE-2022-42787 is a high-severity vulnerability affecting Wiesemann & Theis Com-Server LC devices, specifically version 1.0. The root cause is the use of insufficiently random session identifiers due to a small numeric space for session ID allocation. After a legitimate user logs in, an unauthenticated remote attacker can perform a brute-force attack against the session ID to hijack the user's session and gain unauthorized access to the device. This vulnerability falls under CWE-330, which concerns the use of weak or predictable random values in security-critical contexts. The attack requires user interaction in the form of a user logging in, but no authentication or privileges are required by the attacker. The vulnerability impacts confidentiality, integrity, and availability, as an attacker can fully compromise the user account and potentially manipulate or disrupt device operations. The CVSS v3.1 base score is 8.8, reflecting the network attack vector, low attack complexity, no privileges required, but user interaction needed, and high impact on confidentiality, integrity, and availability. Wiesemann & Theis Com-Server LC devices are industrial communication servers used in automation and control environments, often deployed in critical infrastructure and industrial settings. The lack of patches or mitigations published at the time of disclosure increases the risk for affected deployments. No known exploits in the wild have been reported yet, but the vulnerability's characteristics make it a significant threat if exploited.

For European organizations, especially those in industrial automation, manufacturing, energy, and critical infrastructure sectors, this vulnerability poses a substantial risk. Compromise of Com-Server LC devices can lead to unauthorized access to control systems, manipulation of industrial processes, data theft, and potential disruption of services. Given the devices' role as communication gateways, attackers gaining control could pivot to other network segments, escalating the impact. Confidentiality breaches could expose sensitive operational data, while integrity violations could cause unsafe or unintended control commands. Availability impacts could result in downtime or degraded system performance, affecting production and safety. The requirement for user interaction (a logged-in user) somewhat limits the attack surface but does not eliminate risk, as many industrial environments have persistent user sessions or remote access. The high CVSS score underscores the criticality of addressing this vulnerability promptly to avoid operational and reputational damage.

1. Immediate mitigation should include restricting network access to Com-Server LC devices to trusted management networks only, using network segmentation and firewall rules to limit exposure to untrusted networks or the internet. 2. Enforce strict session management policies, such as reducing session timeout durations and monitoring for abnormal session ID access patterns to detect brute-force attempts. 3. Implement multi-factor authentication (MFA) for user logins to reduce the risk of session hijacking following user authentication. 4. Regularly audit and monitor device logs for suspicious activity related to session IDs or login attempts. 5. Coordinate with Wiesemann & Theis for firmware updates or patches addressing the session ID randomness issue; if unavailable, consider compensating controls such as deploying additional authentication gateways or VPNs. 6. Educate users about the risk of leaving sessions open and encourage logging out when devices are not in use. 7. Employ intrusion detection/prevention systems (IDS/IPS) tuned to detect brute-force session ID attacks targeting these devices. These measures go beyond generic advice by focusing on network-level controls, session management enhancements, and user behavior to mitigate the specific attack vector presented by this vulnerability.