Detections
Analytics

Xen Migrating Timers Race condition DoS (XSA-336)

medium Nessus Plugin ID 141836

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Synopsis

The remote Xen hypervisor installation is missing a security update.

Description

According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by a denial of service (DoS) vulnerability. When migrating timers of x86 HVM guests between its vCPU-s, the locking model used allows for a second vCPU of the same guest also operating on the timers to release a lock that it didn't acquire. An attacker can exploit this issue to crash the hypervisor and cause a DoS condition.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Apply the appropriate patch according to the vendor advisory.

See Also

https://xenbits.xen.org/xsa/advisory-336.html

Plugin Details

Severity: Medium

ID: 141836

File Name: xen_server_XSA-336.nasl

Version: 1.3

Type: local

Family: Misc.

Published: 10/23/2020

Updated: 11/13/2020

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Low

Base Score: 1.9

Temporal Score: 1.4

Vector: CVSS2#AV:L/AC:M/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2020-25604

CVSS v3

Risk Factor: Medium

Base Score: 4.7

Temporal Score: 4.1

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:xen:xen

Required KB Items: Settings/ParanoidReport, installed_sw/Xen Hypervisor

Exploit Ease: No known exploits are available

Patch Publication Date: 9/22/2020

Vulnerability Publication Date: 9/22/2020

Reference Information

CVE: CVE-2020-25604

IAVB: 2020-B-0056-S