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Xen: x86/AMD: Mismatch in IOMMU Quarantine Page Table Levels (XSA-445)

medium Nessus Plugin ID 186416

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Synopsis

The remote Xen hypervisor installation is missing a security update.

Description

The current setup of quarantine page tables assumes that there are 4 page table levels, however the AMD-Vi IOMMU is configured with 3 page table levels for systems without RAM above the 512 GB boundary. Due to this level mismatch, the sink page the device gets read/write access to is no longer cleared between device assignment, possibly leading to data leaks.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Apply the appropriate patch according to the vendor advisory.

See Also

https://xenbits.xen.org/xsa/advisory-445.html

Plugin Details

Severity: Medium

ID: 186416

File Name: xen_server_XSA-445.nasl

Version: 1.4

Type: local

Family: Misc.

Published: 11/29/2023

Updated: 1/15/2024

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2023-46835

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:xen:xen

Required KB Items: installed_sw/Xen Hypervisor, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 11/14/2023

Vulnerability Publication Date: 11/14/2023

Reference Information

CVE: CVE-2023-46835

IAVB: 2023-B-0090