CVE-2018-15468

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

17/08/2018

Last modified:

03/10/2019

Description

An issue was discovered in Xen through 4.11.x. The DEBUGCTL MSR contains several debugging features, some of which virtualise cleanly, but some do not. In particular, Branch Trace Store is not virtualised by the processor, and software has to be careful to configure it suitably not to lock up the core. As a result, it must only be available to fully trusted guests. Unfortunately, in the case that vPMU is disabled, all value checking was skipped, allowing the guest to choose any MSR_DEBUGCTL setting it likes. A malicious or buggy guest administrator (on Intel x86 HVM or PVH) can lock up the entire host, causing a Denial of Service.

Impact

Vector 3.x

CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 6.00 MEDIUM
Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): High
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x

6.00

Severity 3.x

MEDIUM

Vector 2.0

AV:L/AC:L/Au:N/C:N/I:N/A:C CVSS v2.0 Severity and Metrics:

Base Score: 4.90 MEDIUM
Vector: AV:L/AC:L/Au:N/C:N/I:N/A:C

Attack Vector (AV): Local
Attack Complexity (AC): Low
Authentication (Au): None
Confidentiality (C): None
Integrity (I): None
Availability (A): Complete