CVE-2022-50931: TeamSpeak 3.5.6 Privilege Escalation

CVE-2022-50931 Overview

CVE-2022-50931 is an insecure file permissions vulnerability affecting TeamSpeak 3 version 3.5.6. This vulnerability allows local attackers to replace executable files with malicious binaries due to improper permission controls on the application's installation directory. By exploiting this flaw, attackers can substitute legitimate system executables such as ts3client_win32.exe with custom malicious files, potentially gaining SYSTEM or Administrator-level access on affected systems.

Critical Impact

Local privilege escalation through insecure file permissions enables attackers to execute arbitrary code with elevated privileges by replacing TeamSpeak executables.

Affected Products

• TeamSpeak 3 version 3.5.6
• TeamSpeak 3 Client for Windows (32-bit and 64-bit)
• Systems with improperly configured installation directory permissions

Discovery Timeline

• 2026-01-13 - CVE CVE-2022-50931 published to NVD
• 2026-01-13 - Last updated in NVD database

Technical Details for CVE-2022-50931

Vulnerability Analysis

This vulnerability is classified under CWE-732 (Incorrect Permission Assignment for Critical Resource). The flaw stems from TeamSpeak 3.5.6 failing to properly restrict write access to its installation directory and executable files. When the application is installed with default settings, the file permissions may allow non-privileged local users to modify or replace critical executable files.

The attack requires local access to the system where TeamSpeak is installed. Once an attacker identifies the vulnerable installation, they can replace the legitimate ts3client_win32.exe or other executables in the TeamSpeak directory with a malicious binary. The next time a privileged user or the system launches the TeamSpeak application, the attacker's payload executes with elevated privileges.

Root Cause

The root cause of CVE-2022-50931 lies in improper file permission assignment during the TeamSpeak 3.5.6 installation process. The installer fails to enforce restrictive access controls on the application directory, leaving executable files writable by local users who should not have modification privileges. This violates the principle of least privilege and creates an opportunity for local privilege escalation attacks.

Attack Vector

The attack vector is local, requiring the attacker to have existing access to the target system. The exploitation process involves:

1. Identifying a TeamSpeak 3.5.6 installation with insecure file permissions
2. Creating a malicious executable payload designed to perform privileged operations
3. Replacing the legitimate TeamSpeak executable (e.g., ts3client_win32.exe) with the malicious binary
4. Waiting for a privileged user or scheduled task to execute the modified application
5. Gaining elevated privileges when the malicious payload runs in the privileged context

The vulnerability does not require user interaction beyond the normal execution of the TeamSpeak application, making it a practical avenue for privilege escalation in environments where TeamSpeak is commonly used.

Detection Methods for CVE-2022-50931

Indicators of Compromise

• Unexpected modifications to TeamSpeak executable files, particularly ts3client_win32.exe
• File hash mismatches for TeamSpeak binaries compared to known-good versions
• Unauthorized write access attempts to the TeamSpeak installation directory
• Process execution anomalies where TeamSpeak executables spawn unexpected child processes

Detection Strategies

• Implement file integrity monitoring (FIM) on the TeamSpeak installation directory to detect unauthorized modifications
• Monitor for changes to file permissions on critical application directories
• Deploy endpoint detection rules that alert on executable replacement in application directories
• Review Windows Security Event logs for file modification events (Event ID 4663) targeting TeamSpeak files

Monitoring Recommendations

• Configure SentinelOne to monitor for behavioral anomalies associated with privilege escalation attempts
• Establish baseline hashes for all legitimate TeamSpeak executables and alert on deviations
• Monitor for process execution chains that deviate from normal TeamSpeak behavior
• Implement real-time alerting for file modification events in protected application directories

How to Mitigate CVE-2022-50931

Immediate Actions Required

• Audit file permissions on all TeamSpeak installations and restrict write access to administrators only
• Verify the integrity of TeamSpeak executables by comparing file hashes against known-good values
• Update to the latest version of TeamSpeak from the official downloads page
• Review user access controls to ensure only authorized administrators can modify application files

Patch Information

Users should check the TeamSpeak Official Website for the latest security updates and patches addressing this vulnerability. Review the VulnCheck Advisory on TeamSpeak for additional technical details and remediation guidance. The Exploit-DB #50743 entry provides information about the exploitation technique that should be blocked.

Workarounds

• Manually configure restrictive NTFS permissions on the TeamSpeak installation directory, limiting write access to SYSTEM and Administrators only
• Run TeamSpeak from a protected directory location with enforced access controls
• Implement application whitelisting to prevent execution of unauthorized executables in the TeamSpeak directory
• Deploy endpoint protection solutions like SentinelOne that can detect and block suspicious executable modifications

# Windows PowerShell - Restrict permissions on TeamSpeak directory
# Run as Administrator
$teamSpeakPath = "C:\Program Files\TeamSpeak 3 Client"
icacls $teamSpeakPath /inheritance:r
icacls $teamSpeakPath /grant "SYSTEM:(OI)(CI)F"
icacls $teamSpeakPath /grant "Administrators:(OI)(CI)F"
icacls $teamSpeakPath /grant "Users:(OI)(CI)RX"