Use-After-Free Vulnerability in Linux Kernel's AX.25 Protocol Handling
Summary
DEBIAN-CVE-2024-35887: In the Linux kernel, the following vulnerability has been resolved: ax25: fix use-after-free bugs caused by ax25_ds_del_timer When the ax25 device is detaching, the ax25_dev_device_down() calls ax25_ds_del_timer() to cle... Affects linux versions < 6.8.9-1. Fixed in 6.8.9-1. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, providing essential services for all other parts of the system. It manages hardware resources, system calls, and process scheduling. The AX.25 protocol is used for packet radio communications, and it allows for the establishment of connections over radio frequencies. This vulnerability specifically affects the handling of timers in the AX.25 protocol, which can lead to serious stability issues if exploited.
Vulnerability Detail
In the Linux kernel, a use-after-free vulnerability has been identified in the AX.25 protocol handling. This occurs when the ax25_dev_device_down() function calls ax25_ds_del_timer() to clean up a timer associated with a detaching AX.25 device. If the timer handler is still running when the device is freed, it can lead to a situation where the freed memory is accessed, potentially allowing an attacker to execute arbitrary code or crash the system. This vulnerability is particularly critical in multi-threaded environments where timing and resource management are crucial.
How To Fix
Minimum fixed version
6.8.9-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, it is advisable to avoid using the AX.25 protocol until the system can be updated. Additionally, implementing proper synchronization mechanisms around the timer handling code may help mitigate the risk of exploitation.
Conclusion
The identified use-after-free vulnerability in the Linux kernel's AX.25 protocol handling poses significant risks to system stability and security. It is crucial for users to update their systems to the patched version to mitigate these risks. Utilizing tools like Vulert can help in monitoring and managing vulnerabilities effectively.
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FAQ
A use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed, potentially leading to memory corruption or arbitrary code execution.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. By using the Vulert playground, you can check if your application is affected without any signup.
Exploitation of this vulnerability could lead to system crashes, data corruption, or unauthorized access to system resources, posing significant security risks.
Yes, the vulnerability affects the Linux kernel versions prior to 6.8.9-1. Updating to this version or later will mitigate the risk.
If immediate updates are not possible, consider disabling the AX.25 protocol or implementing additional security measures to limit exposure to the vulnerability.
References
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