CVE-2020-15566 Explained : Impact and Mitigation

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a host OS crash due to incorrect error handling in event-channel port allocation.

Understanding CVE-2020-15566

This CVE highlights a vulnerability in Xen that could lead to a host OS crash when guest OS users manipulate event-channel port allocation.

What is CVE-2020-15566?

The vulnerability in Xen versions 4.10 and later allows guest OS users to crash the host OS by exploiting incorrect error handling in event-channel port allocation. The issue arises from missing error checks, leading to a crash when trying to access the event channel.

The Impact of CVE-2020-15566

The vulnerability can be exploited by guest OS users to crash the host OS, particularly when the administrator configures a guest to allow more than 1023 event channels or when Xen is out of memory.

Technical Details of CVE-2020-15566

This section provides more in-depth technical details about the vulnerability.

Vulnerability Description

The vulnerability arises from incorrect error handling in event-channel port allocation in Xen versions 4.10 and later, allowing guest OS users to crash the host OS.

Affected Systems and Versions

Xen versions 4.10 and later are affected
All architectures are vulnerable

Exploitation Mechanism

The vulnerability occurs due to missing error checks, which result in a crash when attempting to access the event channel.

Mitigation and Prevention

Protecting systems from CVE-2020-15566 requires immediate steps and long-term security practices.

Immediate Steps to Take

Apply patches provided by Xen to address the vulnerability
Monitor and restrict the number of event channels allowed for guest OS

Long-Term Security Practices

Regularly update Xen to the latest version to mitigate known vulnerabilities
Implement proper memory management practices to prevent out-of-memory crashes

Patching and Updates

Ensure timely installation of security patches released by Xen