CVE-2022-33737 in Access Server
Summary
by MITRE • 07/06/2022
The OpenVPN Access Server installer creates a log file readable for everyone, which from version 2.10.0 and before 2.11.0 may contain a random generated admin password
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/19/2022
The vulnerability identified as CVE-2022-33737 affects the OpenVPN Access Server installer and represents a critical security flaw in the software's permission handling during installation processes. This issue specifically impacts versions 2.10.0 through 2.10.9, where the installer creates log files with overly permissive access controls that allow any user on the system to read the contents. The vulnerability stems from improper file system permission management during the installation lifecycle, creating a persistent security risk that can be exploited by local attackers with minimal privileges.
The technical flaw manifests in the installer's failure to properly set file permissions on log files that are created during the installation process. These log files contain sensitive information including randomly generated administrator passwords that are automatically created during the installation sequence. The vulnerability is classified under CWE-732 as improper permission management, where the system creates files with world-readable permissions instead of restricting access to authorized users only. This creates a direct path for privilege escalation and unauthorized access to administrative controls of the OpenVPN Access Server.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables local attackers to obtain administrative credentials without requiring additional exploitation techniques. Once an attacker gains access to these log files, they can immediately leverage the extracted administrator passwords to gain full control over the OpenVPN Access Server configuration, user management, and network access policies. This represents a significant risk to organizations that deploy OpenVPN Access Server in environments where local privilege escalation is possible, as the vulnerability can be exploited without requiring network access or advanced attack vectors.
The security implications of this vulnerability align with ATT&CK technique T1078.004 which covers valid accounts with default passwords, and T1566.001 which involves phishing with social engineering. The flaw essentially creates a backdoor through legitimate system administration processes, making it particularly dangerous in enterprise environments where multiple users may have access to the system. Organizations using affected versions of OpenVPN Access Server face potential compromise of their entire VPN infrastructure, as the administrative credentials provide complete control over user authentication, certificate management, and network access policies.
Mitigation strategies for CVE-2022-33737 require immediate action to upgrade to OpenVPN Access Server version 2.11.0 or later, which includes the necessary permission fixes for log file creation. System administrators should also implement manual verification of log file permissions on affected systems, ensuring that any existing log files created during the vulnerable installation process are properly secured with restrictive permissions. Additional defensive measures include implementing regular security audits of system file permissions, monitoring for unauthorized access to system logs, and establishing proper access controls for system administrators to prevent local privilege escalation attacks. The vulnerability demonstrates the critical importance of proper file permission management in installation processes and highlights the need for comprehensive security testing of system administration tools.