CVE-2019-18424

Published Oct 31, 2019

Last updated a year ago

Overview

Description
An issue was discovered in Xen through 4.12.x allowing attackers to gain host OS privileges via DMA in a situation where an untrusted domain has access to a physical device. This occurs because passed through PCI devices may corrupt host memory after deassignment. When a PCI device is assigned to an untrusted domain, it is possible for that domain to program the device to DMA to an arbitrary address. The IOMMU is used to protect the host from malicious DMA by making sure that the device addresses can only target memory assigned to the guest. However, when the guest domain is torn down, or the device is deassigned, the device is assigned back to dom0, thus allowing any in-flight DMA to potentially target critical host data. An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. Only systems where guests are given direct access to physical devices capable of DMA (PCI pass-through) are vulnerable. Systems which do not use PCI pass-through are not vulnerable.
Source
cve@mitre.org
NVD status
Modified

Risk scores

CVSS 3.1

Type
Primary
Base score
6.8
Impact score
5.9
Exploitability score
0.9
Vector string
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity
MEDIUM

CVSS 2.0

Type
Primary
Base score
6.9
Impact score
10
Exploitability score
3.4
Vector string
AV:L/AC:M/Au:N/C:C/I:C/A:C

Weaknesses

nvd@nist.gov
CWE-78

Social media

Hype score
Not currently trending

Configurations