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CVE-2018-15468

Published: 17 August 2018

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.

Notes

AuthorNote
mdeslaur
hypervisor packages are in universe. For
issues in the hypervisor, add appropriate
tags to each section, ex:
Tags_xen: universe-binary

Priority

Medium

Cvss 3 Severity Score

6.0

Score breakdown

Status

Package Release Status
xen
Launchpad, Ubuntu, Debian
hirsute Ignored
(end of life)
groovy Ignored
(end of life)
impish Ignored
(end of life)
focal Not vulnerable
(4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10)
jammy Not vulnerable
(4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10)
kinetic Not vulnerable
(4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10)
bionic Needed

cosmic Ignored
(end of life)
disco Ignored
(end of life)
eoan Ignored
(end of life)
lunar Not vulnerable
(4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10)
trusty Does not exist
(trusty was needs-triage)
upstream
Released (4.11.1~pre.20180911.5acdd26fdc+dfsg-2)
xenial Needed

mantic Not vulnerable
(4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10)
Binaries built from this source package are in Universe and so are supported by the community.

Severity score breakdown

Parameter Value
Base score 6.0
Attack vector Local
Attack complexity Low
Privileges required High
User interaction None
Scope Changed
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H