CVE-2018-15468 Denial of service in n/a
A malicious guest administrator can lock up the entire host by exploiting unvirtualized Branch Trace Store features when vPMU is disabled.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2018-15468?
CVE-2018-15468 is a medium-severity denial of service vulnerability in Xen Xen, published on 17 Aug 2018. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-863
Which versions are affected by CVE-2018-15468?
It affects 1 product.
Products include Xen Xen.
How do I fix CVE-2018-15468?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2018-15468 being exploited?
There is no known exploitation of CVE-2018-15468 in the wild and no public exploit code.
Other vulnerabilities in Xen Xen
Sources
Also known as ALPINE-CVE-2018-15468, DEBIAN-CVE-2018-15468, GHSA-m48w-fvxv-5j3g, UBUNTU-CVE-2018-15468.