CVE-2018-16882 : Vulnerability Insights and Analysis
Learn about CVE-2018-16882 affecting the Linux kernel's KVM hypervisor. Unauthorized users can crash the host kernel or gain elevated privileges. Find mitigation steps and affected versions here.
CVE-2018-16882 was published on January 3, 2019, and affects the Linux kernel's KVM hypervisor. This vulnerability allows unauthorized users to crash the host kernel or potentially gain elevated privileges on systems running kernel versions before 4.14.91 and 4.19.13.
Understanding CVE-2018-16882
This CVE involves a use-after-free issue in the Linux kernel's KVM hypervisor when nested virtualization is enabled.
What is CVE-2018-16882?
The vulnerability arises from errors in handling posted interrupts, leading to a use-after-free issue that can be exploited by unauthorized users within the guest to impact the host system.
The Impact of CVE-2018-16882
- CVSS Base Score: 6.1 (Medium)
- Attack Vector: Local
- Attack Complexity: High
- Privileges Required: High
- Availability Impact: High
- Integrity Impact: Low
- Unauthorized users could crash the host kernel, causing a Denial of Service (DoS) attack or potentially gaining elevated privileges.
Technical Details of CVE-2018-16882
The technical details of this CVE provide insight into the vulnerability's description, affected systems, and exploitation mechanism.
Vulnerability Description
The vulnerability occurs in the nested_get_vmcs12_pages() function due to errors in handling the posted interrupt address, leading to a use-after-free issue.
Affected Systems and Versions
Systems using Linux kernel versions earlier than 4.14.91 and 4.19.13 are vulnerable to this exploit.
Exploitation Mechanism
Unauthorized users or processes within the guest can exploit the unmapped address in pi_test_and_clear_on() to crash the host kernel or gain elevated privileges.
Mitigation and Prevention
To address CVE-2018-16882, immediate steps should be taken to mitigate the vulnerability and prevent potential exploitation.
Immediate Steps to Take
- Update the Linux kernel to version 4.14.91 or 4.19.13 to patch the vulnerability.
- Monitor for any unauthorized access or unusual system behavior.
Long-Term Security Practices
- Implement strict access controls and least privilege principles.
- Regularly update and patch systems to prevent known vulnerabilities.
Patching and Updates
Regularly check for security updates and patches from the Linux Foundation to ensure systems are protected against potential exploits.