CVE-2019-18424
Published: 31 October 2019
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.
Notes
Author | Note |
---|---|
mdeslaur | hypervisor packages are in universe. For issues in the hypervisor, add appropriate tags to each section, ex: Tags_xen: universe-binary |
Priority
Status
Package | Release | Status |
---|---|---|
xen Launchpad, Ubuntu, Debian |
bionic |
Needed
|
disco |
Ignored
(end of life)
|
|
eoan |
Ignored
(end of life)
|
|
focal |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
groovy |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
hirsute |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
impish |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
jammy |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
kinetic |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
lunar |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
mantic |
Not vulnerable
(4.11.3+24-g14b62ab3e5-1ubuntu1)
|
|
trusty |
Does not exist
|
|
upstream |
Needs triage
|
|
xenial |
Needed
|
|
Binaries built from this source package are in Universe and so are supported by the community. |
Severity score breakdown
Parameter | Value |
---|---|
Base score | 6.8 |
Attack vector | Physical |
Attack complexity | Low |
Privileges required | None |
User interaction | None |
Scope | Unchanged |
Confidentiality | High |
Integrity impact | High |
Availability impact | High |
Vector | CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |