CVE-2025-61871 in NAS Navigator2
Summary
by MITRE • 10/10/2025
NAS Navigator2 Windows version by BUFFALO INC. registers a Windows service with an unquoted file path. A user with the write permission on the root directory of the system drive may execute arbitrary code with SYSTEM privilege.
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Analysis
by VulDB Data Team • 10/12/2025
The vulnerability identified as CVE-2025-61871 affects NAS Navigator2 Windows version distributed by BUFFALO INC. This issue stems from a critical service registration flaw where the application creates a Windows service using an unquoted file path in the service configuration. The root cause lies in the improper handling of service installation parameters, specifically the absence of quotation marks around the file path string when registering the service with the Windows Service Control Manager. This configuration oversight creates a privilege escalation vector that can be exploited by malicious actors with write permissions on the system drive root directory.
The technical flaw manifests when a Windows service is registered without proper path quotation, allowing the Windows service manager to interpret the path incorrectly. When the system attempts to start the service, it traverses the directory structure looking for the executable file. If a malicious executable exists in a parent directory along the path, it will be executed instead of the legitimate service binary. This behavior occurs because Windows resolves unquoted paths by searching through each directory component in the path until it finds an executable file. The vulnerability specifically affects the system drive root directory where a user with write permissions can place malicious binaries that will be executed with SYSTEM privileges when the service starts.
The operational impact of this vulnerability is severe as it enables privilege escalation from a standard user account to SYSTEM level access without requiring additional exploitation techniques. An attacker with write permissions on the system drive root directory can simply place a malicious executable with the same name as the service path components, effectively hijacking the legitimate service execution. This creates a persistent backdoor that can be leveraged for further compromise, data exfiltration, or lateral movement within the network. The vulnerability is particularly dangerous because it requires minimal privileges to exploit and provides automatic execution with elevated privileges.
Mitigation strategies for CVE-2025-61871 should focus on both immediate remediation and long-term security hardening. The primary immediate fix involves re-registering the service with properly quoted file paths to prevent path traversal exploitation. Organizations should also implement strict access controls on system drive root directories, ensuring only authorized administrators have write permissions. Additionally, regular security audits should verify all installed services use proper path quoting and that service accounts have minimal required privileges. This vulnerability aligns with CWE-78 and CWE-427 categories related to improper handling of special characters in command line arguments and unquoted service paths. The attack pattern corresponds to techniques described in MITRE ATT&CK matrix under privilege escalation and persistence phases, specifically targeting service execution and registry modification tactics.