CVE-2020-25602 Denial of service in n/a
A malicious x86 PV guest can crash the Xen host by accessing a specific MSR on non-Intel hardware, causing a denial of service.
- 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-2020-25602?
CVE-2020-25602 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 23 Sep 2020. 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 4.14.x. An x86 PV guest can trigger a host OS crash when handling guest access to MSR_MISC_ENABLE. When a guest accesses certain Model Specific Registers, Xen first reads the value from hardware to use as the basis for auditing the guest access. For the MISC_ENABLE MSR, which is an Intel specific MSR, this MSR read is performed without error handling for a #GP fault, which is the consequence of trying to read this MSR on non-Intel hardware. A buggy or malicious PV guest administrator can crash Xen, resulting in a host Denial of Service. Only x86 systems are vulnerable. ARM systems are not vulnerable. Only Xen versions 4.11 and onwards are vulnerable. 4.10 and earlier are not vulnerable. Only x86 systems that do not implement the MISC_ENABLE MSR (0x1a0) are vulnerable. AMD and Hygon systems do not implement this MSR and are vulnerable. Intel systems do implement this MSR and are not vulnerable. Other manufacturers have not been checked. Only x86 PV guests can exploit the vulnerability. x86 HVM/PVH guests cannot exploit the vulnerability.
Weakness: CWE-755
Which versions are affected by CVE-2020-25602?
It affects 4 products.
Products include Debian Debian Linux, Fedoraproject Fedora, Opensuse Leap, Xen Xen.
How do I fix CVE-2020-25602?
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-2020-25602 being exploited?
There is no known exploitation of CVE-2020-25602 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as ALPINE-CVE-2020-25602, DEBIAN-CVE-2020-25602, GHSA-mv4f-fvpr-9x8h, UBUNTU-CVE-2020-25602.