Vulnerability in Kernel: Fix Underflow for the real_dev refcnt
Summary
GSD-2021-1002478: net: vlan: fix underflow for the real_dev refcnt. Affects Kernel versions >= e04a7a84bb77f9cdf4475340fe931389bc72331c, < 6e800ee43218a56acc93676bbb3d93b74779e555. No fix is published. How to fix ↓
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Background
The Kernel is a crucial component of the Linux operating system, responsible for managing system resources and facilitating communication between hardware and software. It provides essential functionalities such as process management, memory management, and device drivers. The vulnerability in question affects the Kernel's VLAN (Virtual Local Area Network) implementation. VLANs allow for the segmentation of a physical network into multiple virtual networks, enabling better network management and security. However, a flaw in the VLAN code leads to an underflow in the reference count for the real_dev, which could have security implications.
Vulnerability Detail
The vulnerability arises from an underflow issue in the reference count for the real_dev in the VLAN code of the Kernel. This underflow can potentially be exploited by an attacker to manipulate the reference count and cause memory corruption or other security issues. The exact impact and attack vectors are yet to be proven, but it is crucial to address this vulnerability to ensure the integrity and security of the system. The vulnerability was introduced in Kernel version v5.10.80 and has been fixed in version v5.10.83.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, if updating the Kernel is not immediately feasible, it is recommended to disable the use of VLANs or limit their usage to trusted networks only. This can be achieved by modifying network configurations to remove or restrict VLAN usage. However, this workaround should be considered temporary, and updating the Kernel to the fixed version is the recommended long-term solution.
Conclusion
In conclusion, the vulnerability in the Kernel's VLAN code poses a potential security risk due to an underflow issue in the reference count for the real_dev. It is crucial to update the Linux Kernel to version v5.10.83 or later to mitigate this vulnerability. Disabling or limiting the use of VLANs can serve as a temporary workaround. For further assistance and support in addressing this vulnerability, please contact DevNack.com.
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FAQ
The exact impact of this vulnerability is yet to be proven. However, it has the potential to lead to memory corruption or other security issues, which could be exploited by attackers.
You can use the Vulert Playground at Vulert Scanner to check if your system is affected by this vulnerability. Simply upload your package-lock.json file, and Vulert will analyze it for any open-source vulnerabilities, including this one.
Yes, a temporary workaround is to disable the use of VLANs or limit their usage to trusted networks only. However, updating the Kernel to the fixed version is the recommended long-term solution.
The vulnerability was introduced in Kernel version v5.10.80 and has been fixed in version v5.10.83. Therefore, versions between v5.10.80 and v5.10.82 are affected.
You can find more information about this vulnerability in the GSD-2021-1002478 entry of the GSD Database maintained by the Cloud Security Alliance. The link to the entry is available in the references section of this report.
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