OpenConnect Vulnerability: Man-in-the-Middle Attack Risk Due to X509_check_ Function Mismanagement
Summary
DEBIAN-CVE-2020-12105: OpenConnect through 8.08 mishandles negative return values from X509_check_ function calls, which might assist attackers in performing man-in-the-middle attacks. Affects openconnect versions 8.10-2 – 9.12-3. No fix is published. How to fix ↓
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Background
OpenConnect is an open-source VPN client that enables secure connections to VPN servers. It is widely used for its compatibility with various VPN protocols and its ability to provide secure internet access. However, versions of OpenConnect up to 8.08 are vulnerable to a specific issue that can be exploited by attackers, potentially compromising the security of the VPN connection.
Vulnerability Detail
The vulnerability identified as CVE-2020-12105 arises from OpenConnect mishandling negative return values from X509_check_ function calls. This flaw can allow attackers to perform man-in-the-middle attacks, intercepting and manipulating the data transmitted between the client and the VPN server. The issue originates from improper error handling in the code, which fails to adequately address negative return values, leading to potential security breaches.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can avoid using OpenConnect versions up to 8.08 until they can update to a patched version. Additionally, consider using alternative VPN clients that do not exhibit this vulnerability.
Conclusion
The OpenConnect vulnerability CVE-2020-12105 poses a significant risk by allowing potential man-in-the-middle attacks due to improper handling of function return values. Users are strongly advised to update to a patched version to ensure their VPN connections remain secure.
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FAQ
CVE-2020-12105 is a vulnerability in OpenConnect that allows for potential man-in-the-middle attacks due to improper handling of return values from X509_check_ function calls.
You can check your version of OpenConnect by running the command 'openconnect --version' in your terminal. If it is 8.08 or earlier, it is vulnerable.
Failing to address this vulnerability could allow attackers to intercept and manipulate your VPN traffic, compromising sensitive data and privacy.
Yes, you can use tools like Vulert, which monitors and alerts in real-time for open-source vulnerabilities in your software using just a manifest file.
More information can be found in the official CVE database or by visiting the Debian security advisory related to CVE-2020-12105.
References
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