CVE-2021-22543 : Security Advisory and Response
Discover the impact of CVE-2021-22543, a high-severity vulnerability in Linux KVM allowing local privilege escalation. Learn about affected systems, exploitation, and mitigation steps.
An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users with the ability to start and control a VM to read/write random pages of memory and can result in local privilege escalation.
Understanding CVE-2021-22543
This CVE pertains to a vulnerability in Linux: KVM that allows users to escalate their privileges locally through improper memory handling.
What is CVE-2021-22543?
CVE-2021-22543 involves a flaw in the way KVM handles memory pages, enabling unauthorized users to access and modify memory pages, potentially leading to privilege escalation.
The Impact of CVE-2021-22543
With a base severity score of 7.7, this CVE has a high impact by allowing attackers to read/write memory pages and potentially escalate their privileges on the system.
Technical Details of CVE-2021-22543
This section provides in-depth technical details about the vulnerability in Linux KVM.
Vulnerability Description
The vulnerability arises from the improper handling of VM_IO|VM_PFNMAP vmas in KVM, which can be exploited to bypass security controls and access memory pages.
Affected Systems and Versions
The affected systems include those running Linux KVM with specific configurations that allow users to control VMs and potentially exploit this vulnerability.
Exploitation Mechanism
Attackers can exploit this vulnerability by leveraging the mishandling of memory pages in KVM, leading to unauthorized access and modification.
Mitigation and Prevention
To mitigate the risks associated with CVE-2021-22543, it is crucial to take immediate steps and adopt long-term security practices.
Immediate Steps to Take
- Apply patches and updates provided by Linux distributions and vendors to address the vulnerability promptly.
Long-Term Security Practices
- Regularly update and patch the system to prevent exploitation of known vulnerabilities.
- Implement least privilege access to restrict unauthorized users from accessing critical system resources.
Patching and Updates
- Keep track of security advisories from Linux distributions and vendors to stay informed about patches and updates related to CVE-2021-22543.