CVE-2018-18656 in PureVPN
Summary
by MITRE
The PureVPN client before 6.1.0 for Windows stores Login Credentials (username and password) in cleartext. The location of such files is %PROGRAMDATA%\purevpn\config\login.conf. Additionally, all local users can read this file.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/06/2020
The vulnerability identified as CVE-2018-18656 represents a critical security flaw in the PureVPN client software for Windows operating systems. This issue stems from the application's improper handling of authentication credentials, specifically storing user login information in an unencrypted format within the system's program data directory. The affected version range includes all PureVPN clients prior to version 6.1.0, making a significant portion of the user base potentially vulnerable to credential theft attacks. The cleartext storage of sensitive information creates an exploitable condition that directly violates fundamental security principles for credential management.
The technical implementation of this vulnerability involves the client application writing authentication credentials to a predictable file path located at %PROGRAMDATA%\purevpn, which is a system directory accessible to various processes and users on the Windows platform. This approach to credential storage lacks any form of encryption or obfuscation, leaving usernames and passwords immediately readable by any entity with access to the system. The vulnerability maps to CWE-312, which specifically addresses the exposure of sensitive information through cleartext storage of credentials, and represents a direct violation of the principle of least privilege and secure credential handling practices. The Windows environment's default file permissions and the location within the program data directory mean that local users, even with limited privileges, could potentially access these files through standard file system operations.
The operational impact of this vulnerability extends beyond simple credential theft, as it creates a persistent security risk that remains active until the affected software is properly updated. Attackers with local access to a compromised system can easily extract login credentials and use them to gain unauthorized access to VPN services, potentially enabling further lateral movement within networks or access to additional systems. The vulnerability creates an attack surface that aligns with the MITRE ATT&CK framework's credential access tactics, specifically targeting the T1550.001 technique for acquiring credentials through the use of stolen credentials. This exposure could lead to unauthorized network access, data exfiltration, and potential compromise of sensitive corporate or personal information, particularly in enterprise environments where VPN usage is prevalent.
The recommended mitigation strategy involves immediate deployment of the PureVPN client version 6.1.0 or later, which addresses the cleartext credential storage issue through proper encryption mechanisms. System administrators should also implement additional monitoring of the %PROGRAMDATA%\purevpn directory to detect any unauthorized access attempts or modifications to credential files. Organizations should conduct vulnerability assessments to identify all systems running affected versions of the PureVPN client and ensure proper patch management procedures are in place. The remediation process should include not only updating the client software but also reviewing and potentially clearing existing credential files from the vulnerable location to prevent exploitation of previously stored information. Security teams should also consider implementing endpoint detection and response solutions that can monitor for suspicious file access patterns in system directories, providing additional defense-in-depth against potential exploitation of this vulnerability.