Citrix XenServer Multiple Vulnerabilities (CTX214954) (Bunker Buster)

high Nessus Plugin ID 92723

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Synopsis

The remote host is affected by multiple vulnerabilities.

Description

The version of Citrix XenServer running on the remote host is missing a security hotfix. It is, therefore, affected by multiple vulnerabilities :

- A privilege escalation vulnerability known as 'Bunker Buster' exists in the paravirtualization (PV) pagetable implementation due to incorrect usage of fast-paths for making updates to pre-existing pagetable entries. An attacker with administrative privileges on a PV guest can exploit this vulnerability to gain administrative privileges on the host operating system. This vulnerability only affects PV guests on x86 hardware;
HVM and ARM guests are not affected. (CVE-2016-6258)

- A denial of service vulnerability exists when handling 32-bit exceptions and event delivery due to missing SMAP whitelisting. A local guest attacker can exploit this to trigger a safety check that will crash other virtual machines on the host system. This vulnerability only exists on 32-bit PV guests running on x86 hardware that supports SMAP. (CVE-2016-6259)

Solution

Apply the appropriate hotfix as referenced in the vendor advisory.

Plugin Details

Severity: High

ID: 92723

File Name: citrix_xenserver_CTX214954.nasl

Version: 1.9

Type: local

Family: Misc.

Published: 8/4/2016

Updated: 7/10/2020

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.5

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

CVSS Score Source: CVE-2016-6258

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:citrix:xenserver

Required KB Items: Host/local_checks_enabled, Host/XenServer/version

Exploit Ease: No known exploits are available

Patch Publication Date: 7/26/2016

Vulnerability Publication Date: 7/26/2016

Reference Information

CVE: CVE-2016-6258, CVE-2016-6259

BID: 92130, 92131

IAVB: 2016-B-0118-S

Detections

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