CVE-2018-12893 : Security Advisory and Response

A problem has been identified in Xen up to version 4.10.x where a safety check introduced in XSA-260 can be triggered by a guest, potentially leading to a Denial of Service attack. This vulnerability affects x86 systems with para-virtualization enabled.

Understanding CVE-2018-12893

Xen vulnerability impacting x86 systems with para-virtualization enabled.

What is CVE-2018-12893?

The vulnerability allows a malicious guest to crash Xen, causing a Denial of Service.
Only x86 systems with para-virtualization enabled are affected.
ARM systems and x86 HVM and PVH guests are not vulnerable.

The Impact of CVE-2018-12893

A malicious guest can exploit the vulnerability to crash Xen, leading to a Denial of Service.
All Xen systems with the XSA-260 fix applied are susceptible to this issue.

Technical Details of CVE-2018-12893

Xen vulnerability details and affected systems.

Vulnerability Description

The safety check introduced in XSA-260 can be triggered by a guest, potentially crashing Xen.
Exploitation requires control over hardware debugging facilities, typically accessible to unprivileged users.

Affected Systems and Versions

Xen systems up to version 4.10.x are impacted.
Only x86 systems with para-virtualization enabled are vulnerable.

Exploitation Mechanism

Malicious x86 para-virtualized guests can exploit the vulnerability.
Attackers need control over hardware debugging facilities to trigger the issue.

Mitigation and Prevention

Steps to mitigate and prevent the CVE-2018-12893 vulnerability.

Immediate Steps to Take

Apply patches provided by Xen to address the vulnerability.
Monitor Xen security advisories for updates and apply them promptly.

Long-Term Security Practices

Regularly update Xen and other software components to the latest versions.
Implement strong access controls to limit guest privileges and prevent unauthorized access.

Patching and Updates

Stay informed about security updates from Xen and apply them as soon as they are available.