CVE-2025-5191 in Utility for DRP-A100
Summary
by MITRE • 08/25/2025
An Unquoted Search Path vulnerability has been identified in the utility for Moxa’s industrial computers (Windows). Due to the unquoted path configuration in the SerialInterfaceService.exe utility, a local attacker with limited privileges could place a malicious executable in a higher-priority directory within the search path. When the Serial Interface service starts, the malicious executable could be run with SYSTEM privileges. Successful exploitation could allow privilege escalation or enable an attacker to maintain persistence on the affected system. While successful exploitation can severely impact the confidentiality, integrity, and availability of the affected device itself, there is no loss of confidentiality, integrity, or availability within any subsequent systems.
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Analysis
by VulDB Data Team • 08/25/2025
The vulnerability identified as CVE-2025-5191 represents a critical unquoted search path weakness in Moxa's industrial computer utility software, specifically within the SerialInterfaceService.exe component. This flaw resides in the Windows environment where the service executable is configured without proper quotation of the search path, creating a predictable execution flow that malicious actors can exploit. The vulnerability is classified under CWE-428 which specifically addresses unquoted search paths, a well-known weakness that has been documented in numerous industrial control systems and embedded environments. The root cause stems from improper configuration management where the system's PATH environment variable contains directories without proper quotation marks, allowing the operating system to search through multiple directories in sequence when resolving executable paths.
The technical exploitation of this vulnerability occurs through a privilege escalation attack vector that leverages the service's automatic execution behavior. When the Serial Interface service starts automatically during system boot or manual invocation, the Windows loader searches through the configured PATH directories without proper path quotation. A local attacker with standard user privileges can place a malicious executable file in a directory that appears earlier in the search path than the legitimate SerialInterfaceService.exe location. This malicious binary, when executed by the service, runs with SYSTEM privileges due to the service's elevated execution context. The attack requires minimal privileges and leverages the inherent trust relationships within the Windows security model, making it particularly dangerous in industrial environments where system integrity is paramount. The vulnerability specifically affects Moxa industrial computers, which are commonly deployed in critical infrastructure environments where maintaining system security and availability is essential.
The operational impact of this vulnerability extends beyond simple privilege escalation, creating potential for persistent compromise and system compromise within industrial control environments. Successful exploitation enables attackers to maintain long-term access to affected systems, potentially allowing them to manipulate industrial processes or exfiltrate sensitive operational data. The vulnerability's presence in industrial computing environments is particularly concerning because these systems often operate continuously and may lack the robust security monitoring found in traditional enterprise environments. While the immediate impact affects only the local device itself, the potential for lateral movement within industrial networks remains significant, as compromised industrial computers can serve as launching points for attacks on connected systems. The vulnerability does not directly compromise downstream systems, but the local compromise represents a significant threat to the overall security posture of industrial operations. This type of vulnerability aligns with ATT&CK technique T1068 which describes local privilege escalation techniques, and T1543 which addresses establishing persistence through service creation or modification.
Mitigation strategies for CVE-2025-5191 should focus on immediate path configuration correction and ongoing monitoring of system integrity. The primary remediation involves properly quoting the search paths in the Windows service configuration to prevent ambiguous path resolution. System administrators should verify that all executable paths in service configurations are properly enclosed in quotation marks, ensuring that the operating system resolves paths correctly without searching through multiple directories. Additionally, implementing least privilege principles and reducing the number of directories in the system PATH variable can significantly limit exploitation opportunities. Regular security assessments should include verification of service configurations and PATH environment variables to prevent similar issues from emerging in other system components. Network segmentation and monitoring solutions should be deployed to detect anomalous execution patterns that might indicate exploitation attempts. Organizations should also consider implementing application whitelisting policies to prevent unauthorized executables from running on industrial systems, particularly in environments where such controls are not already in place. The vulnerability serves as a reminder of the critical importance of proper configuration management in industrial environments where security is often overlooked in favor of operational continuity.