FreeBSD : xen-kernel -- x86: Mishandling of instruction pointer truncation during emulation (49211361-ba4d-11e6-ae1b-002590263bf5)

high Nessus Plugin ID 95501

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Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The Xen Project reports :

When emulating HVM instructions, Xen uses a small i-cache for fetches from guest memory. The code that handles cache misses does not check if the address from which it fetched lies within the cache before blindly writing to it. As such it is possible for the guest to overwrite hypervisor memory.

It is currently believed that the only way to trigger this bug is to use the way that Xen currently incorrectly wraps CS:IP in 16 bit modes. The included patch prevents such wrapping.

A malicious HVM guest administrator can escalate their privilege to that of the host.

Solution

Update the affected packages.

See Also

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214936

https://xenbits.xen.org/xsa/advisory-186.html

http://www.nessus.org/u?1d3f6b81

Plugin Details

Severity: High

ID: 95501

File Name: freebsd_pkg_49211361ba4d11e6ae1b002590263bf5.nasl

Version: 3.4

Type: local

Published: 12/5/2016

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: 8.2

Vector: CVSS:3.0/AV:L/AC:L/PR:H/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: 12/4/2016

Vulnerability Publication Date: 9/8/2016

Reference Information

CVE: CVE-2016-7093