Citrix XenServer Multiple Vulnerabilities (CTX214954) (Bunker Buster)

High Nessus Plugin ID 92723

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VPR Score: 6.5


The remote host is affected by multiple vulnerabilities.


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)


Apply the appropriate hotfix as referenced in the vendor advisory.

See Also

Plugin Details

Severity: High

ID: 92723

File Name: citrix_xenserver_CTX214954.nasl

Version: 1.9

Type: local

Family: Misc.

Published: 2016/08/04

Updated: 2020/07/10

Dependencies: 76770

Risk Information

Risk Factor: High

VPR Score: 6.5

CVSS Score Source: CVE-2016-6258

CVSS v2.0

Base Score: 7.2

Temporal Score: 5.3

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

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

CVSS v3.0

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/XenServer/version, Host/local_checks_enabled

Exploit Available: false

Exploit Ease: No known exploits are available

Patch Publication Date: 2016/07/26

Vulnerability Publication Date: 2016/07/26

Reference Information

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

BID: 92130, 92131

IAVB: 2016-B-0118-S