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Xen Missed Flush DoS or Privilege Escalation (XSA-366)

high Nessus Plugin ID 148843

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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 an issue allowing x86 Intel HVM guest OS users to achieve unintended read/write DMA access, and possibly cause a denial of service (host OS crash) or gain privileges. This occurs because a backport missed a flush, and thus IOMMU updates were not always correct. NOTE: this issue exists because of an incomplete fix for CVE-2020-15565.

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-366.html

Plugin Details

Severity: High

ID: 148843

File Name: xen_server_XSA-366.nasl

Version: 1.3

Type: local

Family: Misc.

Published: 4/20/2021

Updated: 1/26/2022

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 4.4

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

CVSS Score Source: CVE-2021-27379

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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: 2/18/2021

Vulnerability Publication Date: 2/18/2021

Reference Information

CVE: CVE-2021-27379

IAVB: 2021-B-0011-S