CVE-2017-17809 in VyprVPN
Summary
by MITRE
In Golden Frog VyprVPN before 2.15.0.5828 for macOS, the vyprvpnservice launch daemon has an unprotected XPC service that allows attackers to update the underlying OpenVPN configuration and the arguments passed to the OpenVPN binary when executed. An attacker can abuse this vulnerability by forcing the VyprVPN application to load a malicious dynamic library every time a new connection is made.
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Analysis
by VulDB Data Team • 12/17/2019
The vulnerability identified as CVE-2017-17809 represents a critical security flaw in Golden Frog VyprVPN client software for macOS systems. This issue affects versions prior to 2.15.0.5828 and stems from improper access controls within the vyprvpnservice launch daemon component. The vulnerability manifests through an unprotected XPC (Cross-Process Communication) service that exposes functionality typically restricted to authorized processes. XPC services are designed to facilitate secure communication between different processes on macOS, but in this case, the service lacks proper authentication mechanisms that would normally prevent unauthorized access.
The technical flaw lies in the absence of proper privilege checking and access control validation within the XPC service implementation. When an attacker can interact with this service without proper authentication, they gain the ability to manipulate the OpenVPN configuration parameters and command-line arguments that are passed to the OpenVPN binary during execution. This creates a persistent attack vector that can be exploited repeatedly throughout the system's operation. The vulnerability specifically allows for the injection of malicious dynamic libraries into the VPN connection process, which executes every time a new connection is established, making it particularly dangerous for long-running sessions.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise through code injection. Attackers can leverage this weakness to execute arbitrary code within the context of the VPN service, potentially gaining elevated privileges and persistent access to the compromised system. The ability to force the loading of malicious dynamic libraries means that attackers can effectively modify the behavior of the VPN client without requiring user interaction or elevated privileges. This creates a stealthy attack vector that can remain undetected while providing attackers with continuous access to the compromised system, particularly when the VPN client is running with elevated privileges during connection establishment.
The vulnerability aligns with CWE-284, which describes inadequate access control mechanisms, and represents a classic example of improper privilege management in system services. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation through service manipulation and persistence mechanisms. The attack surface is particularly concerning because it operates at the system level through launch daemons, which typically run with elevated privileges and have broad system access. Organizations should consider implementing network monitoring to detect anomalous XPC service communications and ensure that all VPN client software is updated to versions that properly secure these communication channels. The recommended mitigation involves upgrading to VyprVPN version 2.15.0.5828 or later, which addresses the unprotected XPC service by implementing proper authentication and access control checks. Additionally, system administrators should review and restrict XPC service access through appropriate entitlements and sandboxing policies to prevent similar vulnerabilities in other applications.