Vulnerability in vhost/vsock package: Owner Check Bypass in vhost_vsock_stop()

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Background

The vhost/vsock package is a component of the Linux Kernel, which provides support for virtual sockets in a virtualized environment. It allows communication between the host and guest operating systems. The vhost/vsock package is responsible for managing the lifecycle of vhost-vsock devices. These devices enable communication between the host and guest through a socket-like interface.

The vulnerability in the vhost/vsock package allows an attacker to bypass the owner check during the release of vhost-vsock devices. This check is intended to ensure that only the owner of a vhost-vsock device can release it. By bypassing this check, an attacker with access to a vhost-vsock device can release it, potentially leading to unauthorized access or denial of service.

Vulnerability Detail

The vulnerability arises from a missing owner check in the vhost_vsock_stop() function of the vhost/vsock package. This function is responsible for releasing a vhost-vsock device. However, it does not verify the owner of the device before releasing it. This oversight allows an attacker with access to a vhost-vsock device to release it, even if they are not the owner.

The impact of this vulnerability can vary depending on the context. If an attacker gains unauthorized access to a vhost-vsock device, they may be able to intercept or manipulate the communication between the host and guest operating systems. This could lead to information disclosure or privilege escalation. Additionally, an attacker could repeatedly release vhost-vsock devices, causing a denial of service by disrupting the communication between the host and guest.

sudo apt update
sudo apt upgrade

Workaround

As a workaround, users can disable the vhost/vsock functionality if it is not required in their environment. This can be achieved by blacklisting the vhost_vsock module.

To blacklist the vhost_vsock module on a Linux system, create a new file named vhost_vsock.conf in the /etc/modprobe.d/ directory with the following content:

blacklist vhost_vsock

After creating the file, reboot the system for the changes to take effect. This will prevent the vhost/vsock package from being loaded and mitigate the vulnerability.

Conclusion

In conclusion, the vhost/vsock package in the Linux Kernel is vulnerable to a bypass of the owner check during the release of vhost-vsock devices. This can lead to unauthorized access or denial of service. It is recommended to update the Linux Kernel to version v4.19.232 or later to fix this vulnerability. Alternatively, users can disable the vhost/vsock functionality by blacklisting the vhost_vsock module. For further support on vulnerability remediation, please contact DevNack.com.

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