A newly disclosed vulnerability, identified as CVE-2023-7224, affects OpenVPN Connect versions 3. through 3.4.6 on macOS platforms. This security flaw allows local users with limited privileges to execute arbitrary code in external third-party libraries loaded by the OpenVPN Connect client. The vulnerability exploits the macOS dynamic library loading mechanism via the DYLD_INSERT_LIBRARIES environment variable.
OpenVPN Connect is an open-source VPN client that works on multiple platforms, including Windows, macOS, Linux, iOS, and Android. It is a widely used VPN solution for personal and business purposes, providing a secure encrypted connection between a user's device and the VPN server.
In this post, we will discuss the details of CVE-2023-7224, including how the vulnerability can be exploited, its potential impact, and the possible mitigations to protect affected installations.
Vulnerability Details
CVE-2023-7224 specifically targets OpenVPN Connect clients running on macOS systems. The flaw allows a local attacker to load and execute malicious code within the context of the main OpenVPN Connect process. The attacker does this by modifying the DYLD_INSERT_LIBRARIES environment variable, which controls the dynamic loading of external libraries in macOS applications.
By setting this variable to point to a malicious library, a well-crafted exploit can force the OpenVPN Connect client to load that library and execute the embedded code. The code, in turn, can perform various nefarious tasks, such as hijacking the user's VPN connection or monitoring their VPN traffic. The attacker can also leverage other vulnerabilities in the OpenVPN Connect client for further escalation and achieving complete control over the user's machine.
Proof of Concept
The following code snippet demonstrates how an attacker could manipulate the DYLD_INSERT_LIBRARIES environment variable to load an external malicious library:
import os
import subprocess
# Assuming the attacker has control over the "/tmp/malicious_library.dylib" file
os.environ['DYLD_INSERT_LIBRARIES'] = '/tmp/malicious_library.dylib'
subprocess.Popen(['/Applications/OpenVPN Connect/OpenVPN Connect.app/Contents/MacOS/OpenVPN Connect'])
When this code is executed, the OpenVPN Connect client will load the "/tmp/malicious_library.dylib" file and execute the code contained within it.
The CVE-2023-7224 vulnerability was originally disclosed through this public security advisory
The OpenVPN Connect GitHub page offers users more information on the application and its source code
- OpenVPN Connect GitHub Repository
Exploit Details and Mitigations
To mitigate and remediate the risks associated with CVE-2023-7224, OpenVPN, Inc. recommends users update their macOS application to the most recent version, which incorporates a fix for the vulnerability. OpenVPN Connect version 3.4.7 or later contains the necessary security patches, which can be downloaded from the OpenVPN website:
- OpenVPN Connect Client Download Page
Additionally, organizations should ensure that their macOS devices are equipped with up-to-date antivirus software, firewall configurations, and other security best practices to further prevent the risks associated with potential malicious code execution.
In summary, CVE-2023-7224 is a severe vulnerability that affects OpenVPN Connect clients running on macOS systems and can lead to unauthorized code execution. Users and organizations using the affected macOS client versions should immediately update to the latest version to protect their systems from potential exploits targeting this vulnerability.
Timeline
Published on: 01/08/2024 14:15:47 UTC
Last modified on: 01/11/2024 17:33:31 UTC