CVE-2021-28694 : Exploit Details and Defense Strategies
Uncover the impact of CVE-2021-28694, an IOMMU page mapping vulnerability affecting Xen hypervisor environments. Learn about affected systems, exploitation risks, and mitigation strategies.
This CVE article provides insights into CVE-2021-28694, focusing on IOMMU page mapping issues impacting x86 systems running the Xen hypervisor.
Understanding CVE-2021-28694
CVE-2021-28694 involves IOMMU page mapping issues on x86 systems, particularly affecting Xen hypervisor environments.
What is CVE-2021-28694?
The vulnerability stems from the failure of Xen to prevent guests from modifying memory mappings specified in ACPI tables. On AMD systems, this flaw can lead to identity-mapping issues, posing privilege escalation, denial of service, or information leaks.
The Impact of CVE-2021-28694
The specific impact varies depending on the system but may result in privilege escalation, denial of service, or information leaks on affected systems.
Technical Details of CVE-2021-28694
This section delves into the technical aspects of CVE-2021-28694, shedding light on the vulnerability's description, affected systems, and exploitation mechanisms.
Vulnerability Description
The vulnerability allows guests to alter ACPI table mappings, potentially leading to unauthorized access to memory ranges and associated security risks.
Affected Systems and Versions
Xen versions 4.11.x, xen-unstable, 4.12.x, 4.13.x, 4.14.x, and 4.15.x are confirmed to be impacted by CVE-2021-28694.
Exploitation Mechanism
Exploitation typically requires guests with access to physical devices using PCI passthrough, exposing them to the identified memory mapping vulnerabilities.
Mitigation and Prevention
Learn how to protect your systems against CVE-2021-28694 through immediate actions and long-term security practices.
Immediate Steps to Take
Restricting untrusted guest access to physical devices and closely monitoring ACPI table mappings can help mitigate the vulnerability promptly.
Long-Term Security Practices
Implement comprehensive security measures to prevent unauthorized memory access and regularly update Xen to patched versions.
Patching and Updates
Stay informed about security advisories and promptly apply patches released by Xen to safeguard your systems.