Use-After-Free Vulnerability in phylib Package
Summary
GSD-2022-1000158: phylib: fix potential use-after-free. Affects Kernel versions >= bafbdd527d569c8200521f2f7579f65a044271be, < f39027cbada43b33566c312e6be3db654ca3ad17. No fix is published. How to fix ↓
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Background
The phylib package is a component of the Linux Kernel, which is responsible for managing physical layer devices. It provides a framework for handling various types of PHYs (Physical Layer Transceivers) used in networking. PHYs are responsible for transmitting and receiving data over physical media such as Ethernet cables.
The vulnerability identified in phylib is a use-after-free issue, which occurs when a program continues to use a pointer after the memory it points to has been freed. This can lead to unpredictable behavior, including crashes, data corruption, and potential security vulnerabilities.
Vulnerability Detail
The use-after-free vulnerability in phylib was introduced in version v4.16 of the Linux Kernel by commit bafbdd527d569c8200521f2f7579f65a044271be. It was fixed in version v5.4.176 by commit f39027cbada43b33566c312e6be3db654ca3ad17.
This vulnerability could be exploited by an attacker to execute arbitrary code or cause a denial-of-service condition. By manipulating the freed memory, an attacker may be able to control program flow, leading to the execution of malicious code. The impact and attack plausibility of this vulnerability have not been proven yet.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can disable the affected functionality by unloading the phylib module. This can be done using the following command:
$ rmmod phylib
However, this workaround may result in the loss of certain networking capabilities that rely on phylib. It is recommended to apply the official fix by updating the Linux Kernel as soon as possible.
Conclusion
The use-after-free vulnerability in the phylib package of the Linux Kernel can potentially lead to arbitrary code execution or denial-of-service attacks. It is crucial to update the Linux Kernel to version v5.4.176 or later to mitigate this vulnerability. Users can also check if their application is affected by using Vulert's playground at https://vulert.com/scanner without any signup.
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FAQ
phylib is a component of the Linux Kernel that provides a framework for managing physical layer devices, such as PHYs used in networking.
A use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed. This can lead to unpredictable behavior and potential security vulnerabilities.
By manipulating the freed memory, an attacker may be able to control program flow and execute arbitrary code or cause a denial-of-service condition.
The impact and attack plausibility of this vulnerability have not been proven yet.
To fix this vulnerability, update the Linux Kernel to version v5.4.176 or later by pulling the latest changes from the official Linux Kernel repository.
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