CVE-2020-37100: Sync Breeze Privilege Escalation Flaw

CVE-2020-37100 Overview

Sync Breeze Enterprise 12.4.18 contains an unquoted service path vulnerability (CWE-428) that allows local attackers to execute arbitrary code with elevated system privileges. Attackers can exploit the unquoted binary path by placing malicious executables in specific file system locations to hijack the service startup process.

Critical Impact

Local privilege escalation allows attackers with limited user access to gain SYSTEM-level privileges, enabling complete system compromise through service path hijacking.

Affected Products

• Sync Breeze Enterprise 12.4.18
• Sync Breeze Enterprise (prior vulnerable versions)

Discovery Timeline

• 2026-02-03 - CVE CVE-2020-37100 published to NVD
• 2026-02-03 - Last updated in NVD database

Technical Details for CVE-2020-37100

Vulnerability Analysis

This vulnerability stems from improper handling of the Windows service executable path during service registration. When Sync Breeze Enterprise installs its Windows service, the binary path is stored in the registry without proper quotation marks around the path string. Windows service paths containing spaces that are not enclosed in quotes create an exploitable condition where the Service Control Manager (SCM) attempts to resolve the path ambiguously.

The vulnerability is classified under CWE-428 (Unquoted Search Path or Element), which occurs when a service executable path contains spaces but lacks proper quotation marks. This allows an attacker to place a malicious executable in a parent directory that Windows will execute instead of the intended service binary.

Root Cause

The root cause is the failure to enclose the service binary path in quotation marks during service installation. When the Sync Breeze service is registered with Windows, the ImagePath registry value under HKLM\SYSTEM\CurrentControlSet\Services\ stores the path without quotes. If the installation path contains spaces (such as C:\Program Files\Sync Breeze Enterprise\bin\syncbrs.exe), Windows parses this path incorrectly, attempting to execute files at intermediate locations before reaching the correct executable.

Attack Vector

The attack requires local access to the system where Sync Breeze Enterprise is installed. An attacker with low-privilege write access to certain directories in the service path can place a malicious executable that Windows will execute with SYSTEM privileges when the service starts.

For example, if the service path is C:\Program Files\Sync Breeze Enterprise\bin\syncbrs.exe, Windows will attempt to execute in order:

1. C:\Program.exe
2. C:\Program Files\Sync.exe
3. C:\Program Files\Sync Breeze\Enterprise\bin\syncbrs.exe

If an attacker can write a malicious Program.exe to C:\ or Sync.exe to C:\Program Files\, their code will execute with elevated SYSTEM privileges when the service restarts. Detailed technical information is available in the Exploit-DB advisory and the VulnCheck Advisory on SyncBreeze.

Detection Methods for CVE-2020-37100

Indicators of Compromise

• Unexpected executable files named Program.exe, Sync.exe, or similar in C:\ or C:\Program Files\ directories
• New or modified files in directories along the Sync Breeze service path
• Unusual process spawning from the Sync Breeze service with unexpected child processes
• Windows Event Log entries showing service failures followed by unexpected code execution

Detection Strategies

• Query Windows services for unquoted paths using wmic service get name,displayname,pathname,startmode | findstr /i "auto" | findstr /i /v "c:\windows\\" | findstr /i /v """ to identify vulnerable services
• Monitor file creation events in root and Program Files directories for suspicious executables
• Implement SentinelOne Singularity platform behavioral detection rules to identify privilege escalation attempts via service path manipulation
• Use registry monitoring to detect changes to service ImagePath values

Monitoring Recommendations

• Enable auditing on directories commonly exploited in unquoted service path attacks (C:\, C:\Program Files\)
• Configure SentinelOne to alert on new executable creation in high-risk filesystem locations
• Monitor Windows Security Event ID 4688 (Process Creation) for processes spawned by the Sync Breeze service with unexpected binary paths

How to Mitigate CVE-2020-37100

Immediate Actions Required

• Review the Sync Breeze service registry entry and manually add quotation marks around the ImagePath value
• Audit filesystem permissions to ensure non-administrative users cannot write to C:\ or C:\Program Files\ directories
• Scan the system for any suspicious executables that may have already been placed along the service path
• Consider upgrading to a patched version of Sync Breeze Enterprise if available from the official vendor site

Patch Information

Organizations should check the SyncBreeze Official Site for updated versions that address this vulnerability. Until a patch is applied, the registry-based workaround below should be implemented to properly quote the service path.

Workarounds

• Manually edit the service registry entry to add quotation marks around the executable path
• Restrict write permissions on all directories in the service path hierarchy
• Use Windows Group Policy to prevent unauthorized executable creation in system directories
• Implement application whitelisting to prevent unauthorized executables from running

# Registry fix to quote the service path (run as Administrator in PowerShell)
$serviceName = "syncbrs"
$regPath = "HKLM:\SYSTEM\CurrentControlSet\Services\$serviceName"
$currentPath = (Get-ItemProperty -Path $regPath -Name ImagePath).ImagePath
if ($currentPath -notmatch '^".*"$') {
    Set-ItemProperty -Path $regPath -Name ImagePath -Value "`"$currentPath`""
    Write-Host "Service path has been quoted successfully"
}