Xen Hypervisor New CPU Interrupt Descriptor Table (IDT) Copy Handling Guest-to-Host Privilege Escalation (XSA-244)

Medium Nessus Plugin ID 103979

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 an unspecified flaw that is triggered when, as a new CPU is brought online, it copies certain selector fields from CPU0's Interrupt Descriptor Table (IDT) while CPU0 is in HVM context. This may result in incorrect values being copied, allowing an attacker on the guest to cause a denial of service or gain elevated privileges on the host.

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

http://xenbits.xen.org/xsa/advisory-244.html

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

Plugin Details

Severity: Medium

ID: 103979

File Name: xen_server_XSA-244.nasl

Version: 1.5

Type: local

Family: Misc.

Published: 2017/10/19

Updated: 2018/08/08

Dependencies: 78089

Configuration: Enable paranoid mode

Risk Information

Risk Factor: Medium

CVSS v2.0

Base Score: 6.9

Temporal Score: 5.4

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

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

CVSS v3.0

Base Score: 7.5

Temporal Score: 6.7

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

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

Vulnerability Information

CPE: cpe:/o:xen:xen

Required KB Items: installed_sw/Xen Hypervisor, Settings/ParanoidReport

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2017/10/12

Vulnerability Publication Date: 2017/10/12

Reference Information

CVE: CVE-2017-15588, CVE-2017-15589, CVE-2017-15590, CVE-2017-15591, CVE-2017-15592, CVE-2017-15593, CVE-2017-15594, CVE-2017-15595, CVE-2017-15596

BID: 101490, 101496, 101500

IAVB: 2017-B-0142