Incorrect Authorization Affecting xen package, versions <4.11.1-r0


0.0
medium

Snyk CVSS

    Attack Complexity Low
    Privileges Required High
    Scope Changed
    Availability High

    Threat Intelligence

    EPSS 0.04% (11th percentile)
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NVD
6 medium
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SUSE
5.5 medium

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  • Snyk ID SNYK-ALPINE314-XEN-1308420
  • published 21 Jul 2020
  • disclosed 17 Aug 2018

How to fix?

Upgrade Alpine:3.14 xen to version 4.11.1-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen package and not the xen package as distributed by Alpine. See How to fix? for Alpine:3.14 relevant fixed versions and status.

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.