Xen Multiple Vulnerabilities (XSA-186, XSA-187)

high Nessus Plugin ID 93802
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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 multiple vulnerabilities :

- A flaw exists due to improper handling of instruction pointer truncation when emulating HVM instructions. An attacker on the guest can exploit this to gain elevated privileges on the host. (CVE-2016-7093)

- An overflow condition exists due to x86 HVM guests running with shadow paging using a subset of the x86 emulator to handle the guest writing to pagetables. An attacker on the guest can exploit this to cause a denial of service condition on the host. (CVE-2016-7094)

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-186.html

https://xenbits.xen.org/xsa/advisory-187.html

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

Plugin Details

Severity: High

ID: 93802

File Name: xen_server_XSA-187.nasl

Version: 1.8

Type: local

Family: Misc.

Published: 9/29/2016

Updated: 7/10/2020

Dependencies: xen_server_detect.nbin

Configuration: Enable paranoid mode

Risk Information

VPR

Risk Factor: Medium

Score: 6.5

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: High

Base Score: 8.2

Temporal Score: 7.1

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

Temporal Vector: 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: 9/8/2016

Vulnerability Publication Date: 9/8/2016

Reference Information

CVE: CVE-2016-7093, CVE-2016-7094

BID: 92864, 92865

IAVB: 2016-B-0140-S