GLSA-201703-07 : Xen: Privilege Escalation

High Nessus Plugin ID 99014

Synopsis

The remote Gentoo host is missing one or more security-related patches.

Description

The remote host is affected by the vulnerability described in GLSA-201703-07 (Xen: Privilege Escalation)

In CIRRUS_BLTMODE_MEMSYSSRC mode the bitblit copy routine cirrus_bitblt_cputovideo fails to check wethehr the specified memory region is safe.
Impact :

A local attacker could potentially execute arbitrary code with privileges of Xen (QEMU) process on the host, gain privileges on the host system, or cause a Denial of Service condition.
Workaround :

Running guests in Paravirtualization (PV) mode, or running guests in Hardware-assisted virtualizion (HVM) utilizing stub domains mitigate the issue.
Running HVM guests with the device model in a stubdomain will mitigate the issue.
Changing the video card emulation to stdvga (stdvga=1, vga=”stdvga”, in the xl domain configuration) will avoid the vulnerability.

Solution

All Xen Tools users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose '>=app-emulation/xen-tools-4.7.1-r8'

See Also

https://security.gentoo.org/glsa/201703-07

Plugin Details

Severity: High

ID: 99014

File Name: gentoo_GLSA-201703-07.nasl

Version: 3.4

Type: local

Published: 2017/03/28

Updated: 2018/09/12

Dependencies: 12634

Risk Information

Risk Factor: High

CVSS v2.0

Base Score: 9

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

CVSS v3.0

Base Score: 9.9

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

Vulnerability Information

CPE: p-cpe:/a:gentoo:linux:xen-tools, cpe:/o:gentoo:linux

Required KB Items: Host/local_checks_enabled, Host/Gentoo/release, Host/Gentoo/qpkg-list

Patch Publication Date: 2017/03/28

Reference Information

CVE: CVE-2017-2620

GLSA: 201703-07

IAVB: 2017-B-0024