CVE-2020-25601

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. There is a lack of preemption in evtchn_reset() / evtchn_destroy(). In particular, the FIFO event channel model allows guests to have a large number of event channels active at a time. Closing all of these (when resetting all event channels or when cleaning up after the guest) may take extended periods of time. So far, there was no arrangement for preemption at suitable intervals, allowing a CPU to spend an almost unbounded amount of time in the processing of these operations. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. All Xen versions are vulnerable in principle. Whether versions 4.3 and older are vulnerable depends on underlying hardware characteristics.

References

https://xenbits.xen.org/xsa/advisory-344.html

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

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

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

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

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

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

Details

Source: MITRE

Published: 2020-09-23

Updated: 2021-07-21

Type: CWE-400

Risk Information

CVSS v2

Base Score: 4.9

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

Impact Score: 6.9

Exploitability Score: 3.9

Severity: MEDIUM

CVSS v3

Base Score: 5.5

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

Impact Score: 3.6

Exploitability Score: 1.8

Severity: MEDIUM

Tenable Plugins

View all (15 total)

IDNameProductFamilySeverity
150542SUSE SLES11 Security Update : xen (SUSE-SU-2020:14521-1)NessusSuSE Local Security Checks
medium
150180OracleVM 3.4 : xen (OVMSA-2021-0014)NessusOracleVM Local Security Checks
high
144857Xen lack of preemption in evtchn_reset() / evtchn_destroy() DoS (XSA-344)NessusMisc.
medium
143873SUSE SLES12 Security Update : xen (SUSE-SU-2020:2787-1)NessusSuSE Local Security Checks
medium
143853SUSE SLES12 Security Update : xen (SUSE-SU-2020:2788-1)NessusSuSE Local Security Checks
medium
143805SUSE SLES12 Security Update : xen (SUSE-SU-2020:2822-1)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