CVE Vulnerabilities

CVE-2015-8550

Improper Access Control

Published: Apr 14, 2016 | Modified: Nov 04, 2017
CVSS 3.x
8.2
HIGH
Source:
NVD
CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS 2.x
5.7 MEDIUM
AV:L/AC:L/Au:S/C:P/I:P/A:C
RedHat/V2
7.4 IMPORTANT
AV:A/AC:M/Au:S/C:C/I:C/A:C
RedHat/V3
Ubuntu
MEDIUM

Xen, when used on a system providing PV backends, allows local guest OS administrators to cause a denial of service (host OS crash) or gain privileges by writing to memory shared between the frontend and backend, aka a double fetch vulnerability.

Weakness

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Affected Software

Name Vendor Start Version End Version
Xen Xen - (including) - (including)
Linux Ubuntu precise *
Linux Ubuntu precise/esm *
Linux Ubuntu trusty *
Linux Ubuntu trusty/esm *
Linux Ubuntu upstream *
Linux Ubuntu vivid *
Linux Ubuntu vivid/ubuntu-core *
Linux Ubuntu wily *
Linux-armadaxp Ubuntu precise *
Linux-armadaxp Ubuntu upstream *
Linux-aws Ubuntu upstream *
Linux-ec2 Ubuntu upstream *
Linux-flo Ubuntu esm-apps/xenial *
Linux-flo Ubuntu trusty *
Linux-flo Ubuntu upstream *
Linux-flo Ubuntu vivid *
Linux-flo Ubuntu vivid/stable-phone-overlay *
Linux-flo Ubuntu wily *
Linux-flo Ubuntu xenial *
Linux-flo Ubuntu yakkety *
Linux-fsl-imx51 Ubuntu upstream *
Linux-gke Ubuntu upstream *
Linux-goldfish Ubuntu esm-apps/xenial *
Linux-goldfish Ubuntu trusty *
Linux-goldfish Ubuntu upstream *
Linux-goldfish Ubuntu vivid *
Linux-goldfish Ubuntu wily *
Linux-goldfish Ubuntu xenial *
Linux-goldfish Ubuntu yakkety *
Linux-goldfish Ubuntu zesty *
Linux-grouper Ubuntu trusty *
Linux-grouper Ubuntu upstream *
Linux-hwe Ubuntu upstream *
Linux-hwe-edge Ubuntu upstream *
Linux-linaro-omap Ubuntu precise *
Linux-linaro-omap Ubuntu upstream *
Linux-linaro-shared Ubuntu precise *
Linux-linaro-shared Ubuntu upstream *
Linux-linaro-vexpress Ubuntu precise *
Linux-linaro-vexpress Ubuntu upstream *
Linux-lts-quantal Ubuntu precise *
Linux-lts-quantal Ubuntu precise/esm *
Linux-lts-quantal Ubuntu upstream *
Linux-lts-raring Ubuntu precise *
Linux-lts-raring Ubuntu precise/esm *
Linux-lts-raring Ubuntu upstream *
Linux-lts-saucy Ubuntu precise *
Linux-lts-saucy Ubuntu precise/esm *
Linux-lts-saucy Ubuntu upstream *
Linux-lts-trusty Ubuntu precise *
Linux-lts-trusty Ubuntu precise/esm *
Linux-lts-trusty Ubuntu upstream *
Linux-lts-utopic Ubuntu trusty *
Linux-lts-utopic Ubuntu upstream *
Linux-lts-vivid Ubuntu trusty *
Linux-lts-vivid Ubuntu upstream *
Linux-lts-wily Ubuntu trusty *
Linux-lts-wily Ubuntu upstream *
Linux-lts-xenial Ubuntu upstream *
Linux-maguro Ubuntu trusty *
Linux-maguro Ubuntu upstream *
Linux-mako Ubuntu esm-apps/xenial *
Linux-mako Ubuntu trusty *
Linux-mako Ubuntu upstream *
Linux-mako Ubuntu vivid *
Linux-mako Ubuntu vivid/stable-phone-overlay *
Linux-mako Ubuntu wily *
Linux-mako Ubuntu xenial *
Linux-mako Ubuntu yakkety *
Linux-manta Ubuntu trusty *
Linux-manta Ubuntu upstream *
Linux-manta Ubuntu vivid *
Linux-manta Ubuntu wily *
Linux-mvl-dove Ubuntu upstream *
Linux-qcm-msm Ubuntu precise *
Linux-qcm-msm Ubuntu upstream *
Linux-raspi2 Ubuntu upstream *
Linux-raspi2 Ubuntu vivid/ubuntu-core *
Linux-snapdragon Ubuntu upstream *
Linux-ti-omap4 Ubuntu precise *
Linux-ti-omap4 Ubuntu upstream *
Qemu Ubuntu devel *
Qemu Ubuntu esm-infra/xenial *
Qemu Ubuntu trusty *
Qemu Ubuntu trusty/esm *
Qemu Ubuntu vivid *
Qemu Ubuntu wily *
Qemu Ubuntu xenial *
Qemu Ubuntu yakkety *
Qemu Ubuntu zesty *
Qemu-kvm Ubuntu precise *
Qemu-kvm Ubuntu precise/esm *
Xen Ubuntu devel *
Xen Ubuntu esm-infra/xenial *
Xen Ubuntu precise *
Xen Ubuntu trusty *
Xen Ubuntu vivid *
Xen Ubuntu wily *
Xen Ubuntu xenial *
Xen Ubuntu yakkety *
Xen Ubuntu zesty *

Extended Description

Access control involves the use of several protection mechanisms such as:

When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses:

Potential Mitigations

  • Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
  • Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

References