CVE-2020-8834 : Exploit Details and Defense Strategies

KVM in the Linux kernel on Power8 processors has a conflicting use of HSTATE_HOST_R1, leading to a stack corruption and potential kernel panic.

Understanding CVE-2020-8834

This CVE involves a vulnerability in the Linux kernel affecting Power8 processors.

What is CVE-2020-8834?

The issue arises from conflicting use of HSTATE_HOST_R1 in KVM on Power8 processors.
Attackers with code execution ability in a guest VM's kernel space can trigger a host kernel panic.

The Impact of CVE-2020-8834

CVSS Base Score: 6.5 (Medium Severity)
Attack Vector: Local
Availability Impact: High
Scope: Changed

Technical Details of CVE-2020-8834

This section delves into the specifics of the vulnerability.

Vulnerability Description

Conflicting use of HSTATE_HOST_R1 in KVM on Power8 processors leads to stack corruption.

Affected Systems and Versions

Affected Platforms: PPC Power8
Affected Versions:
Linux kernel 4.8 (custom version)
Linux kernel versions prior to 4.18

Exploitation Mechanism

Attackers running code in a guest VM's kernel space can exploit this vulnerability.

Mitigation and Prevention

Protect systems from CVE-2020-8834 with the following measures.

Immediate Steps to Take

Apply the three Linux kernel commits provided in the solution.

Long-Term Security Practices

Regularly update the Linux kernel to patch vulnerabilities.
Implement strict access controls and monitoring mechanisms.

Patching and Updates

Ensure timely installation of security patches and updates.