CVE-2022-35868 in TIA Multiuser Server
Summary
by MITRE • 02/14/2023
A vulnerability has been identified in TIA Multiuser Server V14 (All versions), TIA Multiuser Server V15 (All versions < V15.1 Update 8), TIA Project-Server (All versions < V1.1), TIA Project-Server V16 (All versions), TIA Project-Server V17 (All versions). Affected applications contain an untrusted search path vulnerability that could allow an attacker to escalate privileges, when tricking a legitimate user to start the service from an attacker controlled path.
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Analysis
by VulDB Data Team • 03/12/2023
This vulnerability resides within Siemens TIA Multiuser Server and TIA Project-Server products across multiple versions, representing a critical untrusted search path weakness that enables privilege escalation attacks. The flaw manifests when legitimate users are tricked into executing services from attacker-controlled directories, allowing adversaries to gain elevated system privileges through malicious code injection. This vulnerability directly maps to CWE-426 Untrusted Search Path, which is categorized under the broader category of privilege escalation vulnerabilities in the CWE taxonomy. The attack vector relies on social engineering techniques where users are deceived into launching services from compromised locations, exploiting the trust relationship between the system and its search paths.
The technical implementation of this vulnerability stems from improper handling of executable paths within the software installation and execution environments. When these applications start services or execute binaries, they traverse search paths without adequate validation of source authenticity or path integrity. This behavior creates opportunities for attackers to place malicious executables in directories that are searched before legitimate system directories, effectively hijacking the execution flow. The vulnerability is particularly dangerous because it leverages user interaction to achieve privilege escalation, making it difficult to detect through automated security scanning alone. Attackers can exploit this by placing malicious binaries in the search path, potentially including DLL files or executables that will be loaded or executed with elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can enable attackers to gain persistent access to industrial control systems and network infrastructure. In industrial environments where these Siemens products are deployed, such as manufacturing plants or process control facilities, the ability to escalate privileges can lead to complete system compromise and potential operational disruptions. The vulnerability affects multiple versions of both TIA Multiuser Server and TIA Project-Server, indicating a widespread issue that could impact numerous operational technology environments. Organizations using these products face significant risk of unauthorized access to critical industrial processes, potentially enabling attackers to manipulate production systems, access sensitive data, or cause physical damage to equipment.
Mitigation strategies for this vulnerability require immediate implementation of several security controls and system hardening measures. Organizations should implement strict path validation procedures and ensure that system search paths are properly secured against unauthorized modifications. The most effective immediate remediation involves applying the vendor-provided patches and updates, specifically targeting versions V15.1 Update 8 and later for TIA Multiuser Server, and V1.1 and later for TIA Project-Server. System administrators should also implement privilege separation techniques, ensuring that service accounts operate with minimal required privileges and that no write access exists in critical system directories. Network segmentation and access controls should be enforced to limit lateral movement, while monitoring systems should be configured to detect suspicious execution patterns or attempts to modify system paths. Additionally, regular security awareness training for personnel handling these systems can help prevent successful social engineering attacks that exploit this vulnerability, as user interaction remains a critical component of the attack chain.