Access Restriction Bypass Affecting xen package, versions [,4.11.1)


Severity

Recommended
0.0
medium
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.04% (15th percentile)

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  • Snyk IDSNYK-UNMANAGED-XEN-2383749
  • published26 Jan 2022
  • disclosed17 Aug 2018
  • creditUnknown

Introduced: 17 Aug 2018

CVE-2018-15468  (opens in a new tab)
CWE-264  (opens in a new tab)

How to fix?

Upgrade xen to version 4.11.1 or higher.

Overview

Affected versions of this package are vulnerable to Access Restriction Bypass. 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.

References

CVSS Scores

version 3.1