CVE-2021-28705 : What You Need to Know
Discover the impact of CVE-2021-28705, a Xen vulnerability that allows DoS attacks. Learn about affected systems, exploitation risks, and mitigation steps.
This CVE-2021-28705 article provides insights into issues with partially successful P2M updates on x86 architecture in Xen. Malicious or buggy guest kernels could exploit this vulnerability resulting in Denial of Service (DoS) attacks. The impact extends to potential privilege escalation and information leaks.
Understanding CVE-2021-28705
CVE-2021-28705 involves issues with P2M updates on x86 architecture in Xen leading to potential DoS attacks and security risks.
What is CVE-2021-28705?
CVE-2021-28705 is a vulnerability in Xen that allows malicious or buggy guest kernels to launch DoS attacks and potentially escalate privileges with information leaks.
The Impact of CVE-2021-28705
The impact of CVE-2021-28705 includes the ability for attackers to mount DoS attacks affecting the entire system while also posing risks of privilege escalation and information leaks.
Technical Details of CVE-2021-28705
CVE-2021-28705 affects various versions of Xen namely 4.14.x, 4.12.x, 4.15.x, xen-unstable, and 4.13.x. It was discovered by Jan Beulich of SUSE.
Vulnerability Description
The vulnerability arises from insufficient error handling in certain PoD cases, leading to partially successful operations not being properly accounted for. The issue impacts page removal and insertion of new pages.
Affected Systems and Versions
Xen versions from 3.4 onwards are affected, with x86 HVM and PVH guests in populate-on-demand mode being vulnerable.
Exploitation Mechanism
Malicious or buggy guest kernels can exploit the vulnerability to mount Denial of Service (DoS) attacks, potentially escalating privileges and causing information leaks.
Mitigation and Prevention
To mitigate CVE-2021-28705, avoid starting x86 HVM or PVH guests in populate-on-demand mode to prevent the vulnerability.
Immediate Steps to Take
Immediate steps include ensuring x86 HVM or PVH guests are not started in populate-on-demand mode.
Long-Term Security Practices
Long-term security practices involve regular security updates and patch management to address vulnerabilities proactively.
Patching and Updates
It is crucial to apply patches released by Xen to address CVE-2021-28705 promptly and maintain system security.