Xen Project Descriptor Table Limit Checking Privilege Escalation Vulnerability (XSA-298)

critical Nessus Plugin ID 130760

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 privilege escalation vulnerability due to improper bounds checking for descriptor table accesses. An authenticated attacker, in user mode on a 32-bit guest, could leverage this vulnerability to elevate privileges to that of the guest kernel. Only 32-bit PV guest user mode can leverage this vulnerability.

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 appropriate patch according to the vendor advisory.

See Also

https://xenbits.xen.org/xsa/advisory-298.html

https://xenbits.xen.org/gitweb/?p=xen.git;a=summary

Plugin Details

Severity: Critical

ID: 130760

File Name: xen_server_XSA-298.nasl

Version: 1.3

Type: local

Family: Misc.

Published: 11/8/2019

Updated: 7/10/2020

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: High

Base Score: 9.3

Temporal Score: 6.9

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

CVSS Score Source: CVE-2019-18425

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

Exploit Ease: No known exploits are available

Patch Publication Date: 10/31/2019

Vulnerability Publication Date: 10/31/2019

Reference Information

CVE: CVE-2019-18425

IAVB: 2019-B-0084-S