CVE-2021-28702 : Vulnerability Insights and Analysis
Learn about CVE-2021-28702, a Xen vulnerability where PCI devices with RMRRs are not correctly deassigned, leading to unpredictable behavior. Find out the impact, affected systems, and mitigation steps.
A detailed analysis of CVE-2021-28702, a vulnerability in Xen related to PCI devices with RMRRs not being correctly deassigned.
Understanding CVE-2021-28702
This section provides insights into the impact, technical details, and mitigation strategies for CVE-2021-28702.
What is CVE-2021-28702?
CVE-2021-28702 involves certain PCI devices in a system being assigned Reserved Memory Regions (RMRRs) which are not properly deassigned, leading to unpredictable behavior and potential security risks.
The Impact of CVE-2021-28702
Administrators of guests with RMRR-using PCI devices can cause denial of service and other issues, including a possible escalation of privilege.
Technical Details of CVE-2021-28702
Here we delve into the specifics of the vulnerability, including its description, affected systems, and exploitation mechanism.
Vulnerability Description
PCI devices with RMRRs not being deassigned correctly can result in IOMMU faults, memory corruption, and other unpredictable behaviors when the assigned device is passed through to a guest.
Affected Systems and Versions
Xen versions less than 4.12 are affected, with specific status for different version ranges. Only Intel x86 systems using PCI passthrough are vulnerable.
Exploitation Mechanism
Guests with RMRR-using PCI devices administered by certain users can exploit this vulnerability for denial of service and potentially privilege escalation.
Mitigation and Prevention
In this section, we discuss immediate steps, long-term security practices, and the importance of patching and updates.
Immediate Steps to Take
Avoid passing through PCI devices with RMRRs to guests to mitigate the risk associated with CVE-2021-28702.
Long-Term Security Practices
Regularly monitor and update Xen systems, follow security best practices, and stay informed about potential vulnerabilities to enhance long-term security.
Patching and Updates
Ensure timely application of security patches from Xen to address vulnerabilities like CVE-2021-28702.