CVE-2020-25602

medium
New! CVE Severity Now Using CVSS v3

The calculated severity for CVEs has been updated to use CVSS v3 by default. CVEs that do not have a CVSS v3 score will fall back CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

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.

References

http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.html

https://lists.fedoraproject.org/archives/list/[email protected]/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/

https://lists.fedoraproject.org/archives/list/[email protected]/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/

https://lists.fedoraproject.org/archives/list/[email protected]/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/

https://security.gentoo.org/glsa/202011-06

https://www.debian.org/security/2020/dsa-4769

https://xenbits.xen.org/xsa/advisory-333.html

Details

Source: MITRE

Published: 2020-09-23

Updated: 2020-11-11

Type: CWE-755

Risk Information

CVSS v2

Base Score: 4.6

Vector: AV:L/AC:L/Au:S/C:N/I:N/A:C

Impact Score: 6.9

Exploitability Score: 3.1

Severity: MEDIUM

CVSS v3

Base Score: 6

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H

Impact Score: 4

Exploitability Score: 1.5

Severity: MEDIUM

Vulnerable Software

Configuration 1

OR

cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:* versions from 4.11.0 to 4.14.0 (inclusive)

Tenable Plugins

View all (11 total)

IDNameProductFamilySeverity
144862Xen missing error handling in MSR_MISC_ENABLE DoS (XSA-333)NessusMisc.
medium
143853SUSE SLES12 Security Update : xen (SUSE-SU-2020:2788-1)NessusSuSE Local Security Checks
medium
143707SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2020:2791-1)NessusSuSE Local Security Checks
medium
143685SUSE SLES12 Security Update : xen (SUSE-SU-2020:2786-1)NessusSuSE Local Security Checks
medium
143637SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2020:2790-1)NessusSuSE Local Security Checks
medium
142854GLSA-202011-06 : Xen: Multiple vulnerabilitiesNessusGentoo Local Security Checks
high
141278Fedora 31 : xen (2020-d46fe34349)NessusFedora Local Security Checks
medium
141270Fedora 33 : xen (2020-306b84fd07)NessusFedora Local Security Checks
medium
141168openSUSE Security Update : xen (openSUSE-2020-1608)NessusSuSE Local Security Checks
medium
141138Debian DSA-4769-1 : xen - security updateNessusDebian Local Security Checks
medium
141102Fedora 32 : xen (2020-f668e579be)NessusFedora Local Security Checks
medium