CVE-2025-36537: TeamViewer Privilege Escalation Vulnerability

CVE-2025-36537 Overview

CVE-2025-36537 is an Incorrect Permission Assignment for Critical Resource vulnerability affecting the TeamViewer Client (Full and Host) in TeamViewer Remote and Tensor products prior to version 15.67 on Windows. This security flaw allows a local unprivileged user to trigger arbitrary file deletion with SYSTEM privileges by leveraging the MSI rollback mechanism. The vulnerability specifically affects Remote Management features including Backup, Monitoring, and Patch Management.

Critical Impact

Local privilege escalation enabling arbitrary file deletion with SYSTEM privileges through MSI rollback abuse

Affected Products

• TeamViewer Remote Client (Full) prior to version 15.67 on Windows
• TeamViewer Remote Client (Host) prior to version 15.67 on Windows
• TeamViewer Tensor Client prior to version 15.67 on Windows

Discovery Timeline

• 2025-06-24 - CVE-2025-36537 published to NVD
• 2025-06-26 - Last updated in NVD database

Technical Details for CVE-2025-36537

Vulnerability Analysis

This vulnerability is classified under CWE-732 (Incorrect Permission Assignment for Critical Resource), indicating a fundamental flaw in how the TeamViewer Client manages file permissions during MSI installer operations. The vulnerability requires local access and involves manipulating the Windows MSI rollback mechanism to achieve unauthorized file operations.

The attack has a local attack vector, meaning an attacker must already have access to the target system. However, once exploited, the impact is significant as the vulnerability allows operations to be performed with SYSTEM-level privileges, the highest privilege level on Windows systems. This makes it particularly dangerous in enterprise environments where lower-privileged users could escalate their access.

Root Cause

The root cause of this vulnerability lies in improper permission assignment during MSI installer operations in the TeamViewer Client. During the MSI rollback process, the application fails to properly validate or restrict file operations, allowing unprivileged users to manipulate the process to delete arbitrary files with elevated SYSTEM privileges.

The vulnerability is limited to the Remote Management features (Backup, Monitoring, and Patch Management), suggesting these components have specific MSI handling code paths that do not properly enforce permission boundaries during rollback operations.

Attack Vector

The attack exploits the Windows MSI rollback mechanism, which is designed to restore a system to its previous state if an installation fails. An attacker with local access and low privileges can manipulate this mechanism within the TeamViewer Client to:

1. Initiate an MSI operation involving the vulnerable Remote Management features
2. Trigger a rollback condition during the installation process
3. Leverage the SYSTEM-level execution context of the MSI rollback to delete arbitrary files

The vulnerability mechanism involves abusing the trust relationship between the MSI installer service (which runs as SYSTEM) and the file operations it performs during rollback. Detailed technical information is available in the TeamViewer Security Bulletin TV-2025-1002.

Detection Methods for CVE-2025-36537

Indicators of Compromise

• Unexpected file deletions in protected system directories or application folders
• Anomalous MSI rollback events in Windows Event Logs involving TeamViewer components
• Process execution chains showing low-privileged user accounts triggering SYSTEM-level file operations
• Suspicious activity involving TeamViewer Remote Management features (Backup, Monitoring, Patch Management)

Detection Strategies

• Monitor Windows Installer logs for abnormal rollback activity associated with TeamViewer MSI packages
• Implement file integrity monitoring on critical system files and directories
• Track process creation events where msiexec.exe spawns child processes with SYSTEM privileges
• Alert on unusual TeamViewer service behavior, particularly around the Remote Management components

Monitoring Recommendations

• Enable verbose logging for Windows Installer operations in enterprise environments
• Deploy endpoint detection rules to identify MSI rollback abuse patterns
• Monitor for privilege escalation attempts from unprivileged user accounts
• Review TeamViewer Client activity logs for anomalous Remote Management operations

How to Mitigate CVE-2025-36537

Immediate Actions Required

• Upgrade TeamViewer Remote and Tensor clients to version 15.67 or later immediately
• Audit systems for any signs of exploitation, particularly unexpected file deletions
• Review user access to systems running vulnerable TeamViewer versions
• Consider temporarily disabling Remote Management features (Backup, Monitoring, Patch Management) until patching is complete

Patch Information

TeamViewer has addressed this vulnerability in version 15.67 of the TeamViewer Client for both Remote and Tensor products. Organizations should update all affected installations as soon as possible. The official security bulletin is available at the TeamViewer Trust Center.

Workarounds

• Restrict local access to systems running vulnerable TeamViewer versions to trusted users only
• Disable the Remote Management features (Backup, Monitoring, Patch Management) if not required for business operations
• Implement application whitelisting to control MSI execution contexts
• Deploy additional endpoint protection monitoring for privilege escalation attempts

# Verify TeamViewer version on Windows systems
# Check installed version via registry
reg query "HKLM\SOFTWARE\TeamViewer" /v Version

# Or check via PowerShell for enterprise deployment verification
Get-ItemProperty "HKLM:\SOFTWARE\TeamViewer" | Select-Object Version