CVE-2025-8069 is a vulnerability classified under CWE-276 (Incorrect Default Permissions) affecting AWS Client VPN on Windows platforms, specifically versions 4.1.0 and 5.0.0. During the installation process, the AWS Client VPN installer references the directory C:\usr\local\windows-x86_64-openssl-localbuild\ssl to retrieve the OpenSSL configuration file. Due to improper permission settings on this directory, a non-administrative user can place or modify files within it, including inserting arbitrary malicious code into the OpenSSL configuration file. When an administrator initiates the installation, the installer executes the code found in this configuration file with elevated privileges, effectively allowing privilege escalation from a limited user to root-level access. This flaw is unique to the Windows client and does not impact Linux or Mac versions of AWS Client VPN. The vulnerability requires local access by a non-admin user and does not require user interaction once the admin starts the installation. The CVSS 4.0 score of 7.3 reflects the high impact on confidentiality, integrity, and availability, combined with the requirement for local privileges and partial authentication. No known exploits are currently reported in the wild, but the risk remains significant due to the potential for unauthorized code execution with administrative rights. AWS recommends discontinuing new installations of vulnerable versions and upgrading to version 5.2.2 or later, which presumably addresses the permission misconfiguration. This vulnerability highlights the critical importance of secure default permissions during software installation processes, especially for security-sensitive components like VPN clients that handle encrypted communications.

The vulnerability allows a non-privileged local user to escalate privileges to root-level by injecting malicious code into the OpenSSL configuration file used during AWS Client VPN installation on Windows. This can lead to full system compromise, including unauthorized access to sensitive data, manipulation or disruption of VPN connections, and potential lateral movement within enterprise networks. For European organizations, the impact is significant as AWS Client VPN is widely used for secure remote access, especially in sectors such as finance, healthcare, and critical infrastructure. Exploitation could undermine confidentiality by exposing encrypted traffic or credentials, compromise integrity by altering VPN configurations or system files, and affect availability by disrupting VPN services. The requirement for local access limits remote exploitation but insider threats or compromised endpoints pose a real risk. The vulnerability could also facilitate persistence mechanisms for attackers within corporate environments. Given the high reliance on AWS services across Europe, especially in countries with advanced cloud adoption, the threat could affect a broad range of organizations, potentially leading to regulatory and compliance repercussions under GDPR if personal data is exposed.

1. Immediately discontinue any new installations of AWS Client VPN on Windows versions prior to 5.2.2. 2. Upgrade all existing AWS Client VPN Windows clients to version 5.2.2 or later, which includes the fix for this permission issue. 3. Restrict local user permissions rigorously to prevent non-admin users from writing to the OpenSSL configuration directory or related installation paths. 4. Implement application whitelisting and integrity monitoring on installation directories to detect unauthorized file modifications. 5. Enforce strict endpoint security controls to limit local user access and monitor for suspicious activities during VPN client installation or updates. 6. Conduct regular audits of installed software versions and patch status across Windows endpoints using AWS Client VPN. 7. Educate system administrators to avoid running installations with elevated privileges unless necessary and to verify the integrity of installation files and directories. 8. Consider deploying endpoint detection and response (EDR) solutions capable of detecting privilege escalation attempts and anomalous code execution during installation processes. 9. For organizations with sensitive environments, isolate VPN client installation activities to controlled administrative workstations to reduce risk of local exploitation. 10. Maintain up-to-date incident response plans to quickly address any suspected exploitation of this vulnerability.