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Microsoft Warns of Increasing Number of Vulnerabilities in OpenVPN
OpenVPN, a popular open source virtual private network (VPN) system integrated into millions of routers, firmware, PCs, mobile devices and other smart devices, is leaving users open to a growing list of threats, according to Microsoft.
The company released a security report detailing some of the latest holes in the open source service, and is warning that many of these vulnerabilities could be used in conjunction "to achieve an attack chain consisting of remote code execution (RCE) and local privilege escalation (LPE)." The report was compiled after Microsoft discussed a handful of new OpenVPN holes during its Black Hat USA 2024 session this week.
Microsoft initially reported these vulnerabilities to OpenVPN in March 2024 through Coordinated Vulnerability Disclosure (CVD) via the Microsoft Security Vulnerability Research (MSVR) team. Following this, Microsoft and OpenVPN worked together to patch the vulnerabilities, culminating in the release of OpenVPN 2.6.10.
The discovered vulnerabilities include:
- CVE-2024-27459: Affects the openvpnserv component, leading to potential denial of service (DoS) and local privilege escalation (LPE) in Windows.
- CVE-2024-24974: Also within openvpnserv, this vulnerability allows unauthorized access to Windows.
- CVE-2024-27903: This flaw can result in remote code execution (RCE) on Windows and LPE or data manipulation on Android, iOS, macOS and BSD.
- CVE-2024-1305: Affects the Windows TAP driver, leading to a potential DoS on Windows.
"All the identified vulnerabilities can be exploited once an attacker gains access to a user's OpenVPN credentials, which could be accomplished using credential theft techniques, such as purchasing stolen credentials on the dark web, using info-stealing malware, or sniffing network traffic to capture NTLMv2 hashes and then using cracking tools like HashCat or John the Ripper to decode them," wrote the Microsoft Threat Intelligence team.
What's interesting is that the discovered vulnerabilities all can be found on the client side. Microsoft stressed that OpennVPN's server is secure, and discovered no holes on that side of the equation.
Microsoft reported these vulnerabilities to OpenVPN in March 2024 through Coordinated Vulnerability Disclosure (CVD) via the Microsoft Security Vulnerability Research (MSVR) team. Following this, Microsoft and OpenVPN worked together to patch the vulnerabilities, culminating in the release of OpenVPN 2.6.10. However, Microsoft said that users are strongly urged to apply the latest security updates to mitigate potential risks as soon as available.
Microsoft advises organizations using OpenVPN are advised to verify their versions and apply the necessary patches immediately. Additionally, ensuring strong credential management and limiting access to VPN services can further mitigate potential risks.