Xen Restartable PV Type Change Operations Elevation of Privilege Vulnerability (XSA-299)

high Nessus Plugin ID 131133

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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 elevation of privilege vulnerability due to race conditions in the pagetable promotion and demotion operations. An authenticated, remote attacker can exploit this issue, by triggering race conditions and cause Xen to drop or retain extra type counts, to get write access to in-use pagetables and potentially gain elevated privileges.

Note that Nessus has checked the changeset versions based on the xen.git change log. Nessus did not check guest hardware configurations or if patches were applied manually to the source code before a recompile and reinstall.

Solution

Apply the appropiate patch according to the vendor advisory.

Plugin Details

Severity: High

ID: 131133

File Name: xen_server_XSA-299.nasl

Version: 1.3

Type: local

Family: Misc.

Published: 11/20/2019

Updated: 7/10/2020

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.1

Temporal Score: 5.3

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

CVSS Score Source: CVE-2019-18421

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:H/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: 10/31/2019

Vulnerability Publication Date: 10/31/2019

Reference Information

CVE: CVE-2019-18421

IAVB: 2019-B-0084-S

Detections

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