Xen Project VCPUOP_initialise DoS (XSA-296)

medium Nessus Plugin ID 130759

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 due to poor handling of an invalid format string in 'hypercall_create_continuation()'. This function can be reached via a long-running 'VCPUOP_initialise' hypercall. This vulnerability may allow an attacker to preform a guest-to-host denial of service attack causing the Xen hypervisor to crash. Only x86 PV guests are exploitable.

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-296.html

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

Plugin Details

Severity: Medium

ID: 130759

File Name: xen_server_XSA-296.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: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 6.3

Temporal Score: 4.7

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

CVSS Score Source: CVE-2019-18420

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

Vector: CVSS:3.0/AV:N/AC:L/PR:L/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: 10/31/2019

Vulnerability Publication Date: 10/31/2019

Reference Information

CVE: CVE-2019-18420

IAVB: 2019-B-0084-S