FreeBSD : xen-kernel -- x86 shadow pagetables: address width overflow (d51ced72-4212-11e6-942d-bc5ff45d0f28)

high Nessus Plugin ID 91934
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Synopsis

The remote FreeBSD host is missing a security-related update.

Description

The Xen Project reports :

In the x86 shadow pagetable code, the guest frame number of a superpage mapping is stored in a 32-bit field. If a shadowed guest can cause a superpage mapping of a guest-physical address at or above 2^44 to be shadowed, the top bits of the address will be lost, causing an assertion failure or NULL dereference later on, in code that removes the shadow.

A HVM guest using shadow pagetables can cause the host to crash.

A PV guest using shadow pagetables (i.e. being migrated) with PV superpages enabled (which is not the default) can crash the host, or corrupt hypervisor memory, and so a privilege escalation cannot be ruled out.

Solution

Update the affected package.

See Also

http://xenbits.xen.org/xsa/advisory-173.html

http://www.nessus.org/u?d342a36e

Plugin Details

Severity: High

ID: 91934

File Name: freebsd_pkg_d51ced72421211e6942dbc5ff45d0f28.nasl

Version: 2.4

Type: local

Published: 7/5/2016

Updated: 1/4/2021

Dependencies: ssh_get_info.nasl

Risk Information

VPR

Risk Factor: Medium

Score: 6.5

CVSS v2

Risk Factor: High

Base Score: 7.2

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

CVSS v3

Risk Factor: High

Base Score: 8.8

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

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:xen-kernel, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Patch Publication Date: 7/4/2016

Vulnerability Publication Date: 4/18/2016

Reference Information

CVE: CVE-2016-3960