UAF in blk_trace Access After Removing by sysfs in Kernel
Summary
UVI-2021-1001501: blktrace: Fix uaf in blk_trace access after removing by sysfs. Affects Kernel versions >= c71a896154119f4ca9e89d6078f5f63ad60ef199, < 488da313edf3abea7f7733efe011c96b23740ab5. No fix is published. How to fix ↓
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Background
The Kernel is a crucial component of the Linux operating system that provides core functionalities and acts as an interface between hardware and software. It manages system resources, facilitates communication between different software components, and ensures the overall stability and security of the system. The blktrace module in the Kernel allows users to trace block I/O events and collect performance data for storage devices. It provides valuable insights into disk I/O patterns and can be used for performance analysis and debugging purposes.
Vulnerability Detail
The identified vulnerability (UVI-2021-1001501) in the blktrace module involves a use-after-free (UAF) issue when accessing blk_trace after it has been removed by sysfs. This vulnerability can potentially be exploited by an attacker to execute arbitrary code or cause a denial-of-service (DoS) condition. The UAF occurs due to improper handling of blk_trace objects after they have been removed, leading to a situation where the memory is accessed after it has been freed. This can result in memory corruption and potentially allow an attacker to gain control over the affected system.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can disable the blktrace module if it is not required for their specific use case. Disabling the module will eliminate the potential attack surface associated with this vulnerability. To disable the blktrace module, the following steps can be followed:
- Open the terminal and switch to the root user.
- Execute the command:
echo 'blacklist blktrace' >> /etc/modprobe.d/blacklist.conf - Reboot the system for the changes to take effect.
Conclusion
The UAF vulnerability in blktrace can pose a significant security risk to Linux systems. It is crucial to promptly update the Kernel to the latest stable version (v4.4.286 or later) to mitigate this vulnerability. Additionally, users can consider disabling the blktrace module if it is not required for their specific use case. For further support and assistance in vulnerability remediation, please contact DevNack.com.
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FAQ
The blktrace module in the Linux Kernel allows users to trace block I/O events and collect performance data for storage devices. It provides valuable insights into disk I/O patterns and can be used for performance analysis and debugging purposes.
A use-after-free (UAF) vulnerability occurs when a program continues to use a memory reference after it has been freed. This can lead to memory corruption and potentially allow an attacker to execute arbitrary code or cause a denial-of-service (DoS) condition.
sysfs is a virtual file system in Linux that provides a structured view of kernel data and devices. It allows users and applications to interact with the kernel and access information about various system components.
The UAF vulnerability in blktrace can potentially be exploited by an attacker to execute arbitrary code or cause a denial-of-service (DoS) condition. This can lead to unauthorized access, data breaches, system instability, and disruption of critical services.
You can use Vulert's playground at Vulert Scanner to check if your system is affected by this vulnerability. Vulert monitors and alerts in real-time for open-source vulnerabilities, using just a manifest file like package-lock.json to provide comprehensive vulnerability information.
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