Vulnerability in Kernel: KVM - Stop looking for coalesced MMIO zones if the bus is destroyed
Summary
GSD-2021-1000439: KVM: Stop looking for coalesced MMIO zones if the bus is destroyed. Affects Kernel versions >= 41b2ea7a6a11e2b1a7f2c29e1675a709a6b2b98d, < 7d1bc32d6477ff96a32695ea4be8144e4513ab2d. 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 acts as an interface between hardware and software. It manages system resources, facilitates communication between different software components, and ensures the security and stability of the system. KVM (Kernel-based Virtual Machine) is a module within the Kernel that enables virtualization on Linux systems, allowing multiple virtual machines to run simultaneously on a single physical machine. It provides a virtualized environment for running guest operating systems.
This vulnerability affects the Kernel and specifically the KVM module.
Vulnerability Detail
The vulnerability in the KVM module arises from a flaw in the handling of coalesced MMIO (Memory Mapped Input/Output) zones when the bus is destroyed. MMIO zones are regions of memory used for communication between the virtual machine and the underlying hardware. When the bus associated with these zones is destroyed, the KVM module should stop looking for coalesced MMIO zones. However, due to the vulnerability, the module continues to search for these zones even after the bus is destroyed.
This vulnerability can potentially be exploited by an attacker with access to a virtual machine to trigger a use-after-free condition or other memory corruption issues. By carefully manipulating the MMIO zones, an attacker may be able to execute arbitrary code, escalate privileges, or cause a denial-of-service condition on the host system.
The vulnerability was introduced in version v5.4.66 of the Linux Kernel and has been fixed in version v5.4.119.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
There is no specific workaround available for this vulnerability. It is recommended to apply the fix by updating the Linux Kernel to the latest version.
Conclusion
The vulnerability in the Kernel's KVM module, which allows the continued search for coalesced MMIO zones even after the associated bus is destroyed, can potentially lead to memory corruption and unauthorized code execution. It is crucial to update the Linux Kernel to version v5.4.119 or later to mitigate this vulnerability. For further support and assistance in vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability can potentially allow an attacker with access to a virtual machine to execute arbitrary code, escalate privileges, or cause a denial-of-service condition on the host system.
You can use the Vulert Playground (https://vulert.com/scanner) to check if your system is affected by this vulnerability. Simply upload your package-lock.json file to the playground, and it will analyze the dependencies and alert you if any vulnerabilities, including this one, are found.
As of now, there is no known exploit for this vulnerability. However, it is important to apply the fix as soon as possible to mitigate any potential risks.
No, this vulnerability requires an attacker to have access to a virtual machine running on the affected system. It cannot be exploited remotely without prior access.
If you are unable to update the Kernel immediately, it is recommended to implement additional security measures such as restricting access to virtual machines, ensuring strong authentication mechanisms, and monitoring for any suspicious activities.
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