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Xen Control Block DoS (XSA-358)

medium Nessus Plugin ID 144783

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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 vulnerability. Recording of the per-vCPU control block mapping maintained by Xen and that of pointers into the control block is reversed. The consumer assumes, seeing the former initialized, that the latter are also ready for use. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system.

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 or workaround according to the vendor advisory.

See Also

https://xenbits.xen.org/xsa/advisory-358.html

Plugin Details

Severity: Medium

ID: 144783

File Name: xen_server_XSA-358.nasl

Version: 1.3

Type: local

Family: Misc.

Published: 1/7/2021

Updated: 6/3/2021

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 3.6

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

CVSS Score Source: CVE-2020-29570

CVSS v3

Risk Factor: Medium

Base Score: 6.2

Temporal Score: 5.4

Vector: CVSS:3.0/AV:L/AC:L/PR:N/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: installed_sw/Xen Hypervisor, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 12/15/2020

Vulnerability Publication Date: 12/15/2020

Reference Information

CVE: CVE-2020-29570

IAVB: 2020-B-0077-S