x86/signal: Detect and prevent an alternate signal stack overflow in Kernel
Summary
UVI-2021-1001272: x86/signal: Detect and prevent an alternate signal stack overflow. Affects Kernel versions >= c2bc11f10a39527cd1bb252097b5525664560956, < 74569cb9ed7bc60e395927f55d3dc3be143a0164. No fix is published. How to fix ↓
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Background
The Kernel is a critical component of the Linux operating system that provides core functionalities and manages system resources. It acts as an interface between the hardware and software layers, facilitating communication and coordination between various processes. The x86/signal module within the Kernel is responsible for handling signals, which are used for inter-process communication and event notification. Signals allow processes to communicate with each other and the operating system, enabling actions such as process termination, error handling, and user-defined notifications. However, a vulnerability has been discovered in the x86/signal module that could potentially lead to an alternate signal stack overflow.
Vulnerability Detail
The x86/signal vulnerability arises from a flaw in the implementation of the alternate signal stack. The alternate signal stack is a separate stack used by the Kernel to handle signals in certain scenarios. When a signal is received, the Kernel switches to the alternate signal stack to execute the signal handler. However, due to a lack of proper bounds checking, an attacker could craft a malicious signal that triggers an overflow in the alternate signal stack. This overflow could potentially lead to a stack-based buffer overflow, allowing the attacker to execute arbitrary code or crash the system. 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 this vulnerability has been fixed in the latest version of the Linux Kernel, there is no specific workaround available. It is strongly advised to update to the patched version to mitigate the risk.
Conclusion
The x86/signal vulnerability in the Kernel exposes a potential risk of an alternate signal stack overflow. To mitigate this vulnerability, it is crucial to update the Linux Kernel to version v5.10.52 or later. This update includes the necessary fix to prevent the overflow and protect the system from potential exploitation. For further support and assistance in vulnerability remediation, please contact DevNack.com.
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FAQ
The impact of this vulnerability could potentially allow an attacker to execute arbitrary code or crash the system by triggering a stack-based buffer overflow.
You can use Vulert's playground (https://vulert.com/scanner) to check if your system is affected by this vulnerability. Vulert monitors and alerts in real-time for open-source vulnerabilities without requiring access to the code or installation.
At the time of this report, there is no known exploit for this vulnerability. However, it is important to apply the patch as soon as possible to prevent potential exploitation.
The exact attack vectors and remote exploitability of this vulnerability have not been proven yet. However, it is always recommended to apply security patches promptly to minimize the risk of remote exploitation.
If updating the Kernel is not immediately feasible, it is recommended to implement other security measures such as network segmentation, access controls, and intrusion detection systems to reduce the risk of exploitation.
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