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Xen INVLPG-like flushes may leave stale TLB entries privilege escalation (XSA-286)

medium Nessus Plugin ID 145062

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Synopsis

The remote Xen hypervisor installation is missing a security update.

Description

A privilege escalation vulnerability exists in Xen x86 PV guest kernels due to mishandles invalidation of TLB entries An unauthenticated, local attacker x86 PV guest OS users to gain guest OS privileges by modifying kernel memory contents, because invalidation of TLB entries is mishandled during use of an INVLPG-like attack technique.

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-286.html

Plugin Details

Severity: Medium

ID: 145062

File Name: xen_server_XSA-286.nasl

Version: 1.3

Type: local

Family: Misc.

Published: 1/19/2021

Updated: 6/3/2021

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2020-27674

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

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

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: 10/20/2020

Vulnerability Publication Date: 10/20/2020

Reference Information

CVE: CVE-2020-27674

CWE: 119

IAVB: 2020-B-0056-S