CVE-2026-33253: SANUPS SOFTWARE Unquoted Path Vulnerability

CVE-2026-33253 Overview

CVE-2026-33253 is an unquoted service path vulnerability in SANUPS SOFTWARE provided by SANYO DENKI CO., LTD. The software registers Windows services with unquoted file paths, allowing a user with write permission on the root directory of the system drive to execute arbitrary code with SYSTEM privilege. This classic Windows privilege escalation technique can be exploited by local attackers to gain complete control over affected systems.

Critical Impact

Local attackers with write access to the system drive root can escalate privileges to SYSTEM level, potentially leading to full system compromise.

Affected Products

• SANUPS SOFTWARE by SANYO DENKI CO., LTD.

Discovery Timeline

• 2026-03-25 - CVE CVE-2026-33253 published to NVD
• 2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-33253

Vulnerability Analysis

This vulnerability (CWE-428: Unquoted Search Path or Element) occurs when Windows services are registered with executable paths that contain spaces but are not enclosed in quotation marks. When Windows attempts to start such a service, it parses the unquoted path and may execute a malicious binary placed strategically in the path hierarchy before reaching the intended executable.

For example, if a service is registered with a path like C:\Program Files\SANYO DENKI\SANUPS\service.exe, Windows will attempt to execute binaries in the following order: C:\Program.exe, C:\Program Files\SANYO.exe, and finally the intended executable. An attacker with write permissions to the system drive root (C:\) can place a malicious executable named Program.exe to intercept service execution.

Root Cause

The root cause of this vulnerability is improper service registration in SANUPS SOFTWARE. During installation, the software registers Windows services with executable paths that contain spaces but fails to enclose these paths in quotation marks. This configuration oversight allows the Windows service control manager to misinterpret the path and potentially execute unintended binaries.

Attack Vector

The attack requires local access to the system and write permissions on the root directory of the system drive (typically C:\). An attacker exploits this vulnerability by:

1. Identifying the unquoted service path in the Windows registry
2. Placing a malicious executable at a path that Windows will attempt to execute before the legitimate service binary
3. Waiting for the service to restart (either through system reboot or manual restart)
4. The malicious executable runs with SYSTEM privileges when the service control manager attempts to start the service

Since Windows services typically run with SYSTEM privileges, successful exploitation grants the attacker the highest level of access on the local system.

Detection Methods for CVE-2026-33253

Indicators of Compromise

• Unexpected executable files in the root of the system drive (e.g., C:\Program.exe, C:\SANYO.exe)
• Anomalous processes spawning with SYSTEM privileges from unusual locations
• Modification timestamps on suspicious executables in path segments of the vulnerable service

Detection Strategies

• Query Windows services for unquoted paths using PowerShell: Get-WmiObject Win32_Service | Where-Object { $_.PathName -match '^[^"].*\s.*[^"]$' }
• Monitor file creation events in the root of system drives and C:\Program Files\ subdirectories
• Implement application whitelisting to prevent unauthorized executables from running
• Use SentinelOne's behavioral AI to detect privilege escalation attempts and anomalous service execution patterns

Monitoring Recommendations

• Enable Windows Security Event logging for service installation and modification (Event IDs 4697, 7045)
• Configure file integrity monitoring on system drive root directories
• Deploy endpoint detection and response (EDR) solutions to identify suspicious process hierarchies
• Alert on any new executable creation in C:\ or early path segments of Program Files

How to Mitigate CVE-2026-33253

Immediate Actions Required

• Review all SANUPS SOFTWARE service registrations for unquoted paths
• Apply vendor-provided patches or updates as soon as available
• Restrict write permissions on the system drive root directory to administrators only
• Audit and remove any suspicious executables from path segments that could be exploited

Patch Information

SANYO DENKI CO., LTD. has released documentation addressing this vulnerability. Administrators should review the official security advisories and apply the recommended fixes. For detailed patch information, refer to the JVN Security Advisory JVN90835713 and the vendor's product documentation available in English and Japanese.

Workarounds

• Manually correct the service path by adding quotation marks around the executable path in the Windows registry
• Remove write permissions from the system drive root for non-administrative users
• Implement application control policies to prevent execution of unauthorized binaries
• Consider running affected services under dedicated service accounts with minimal privileges until patches are applied

# PowerShell command to identify unquoted service paths
Get-WmiObject Win32_Service | Where-Object { $_.PathName -match '^[^"].*\s.*[^"]$' } | Select-Object Name, PathName