Debian DSA-5378-1 : xen - security update

high Nessus Plugin ID 173415

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Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-5378 advisory.

- IBPB may not prevent return branch predictions from being specified by pre-IBPB branch targets leading to a potential information disclosure. (CVE-2022-23824)

- x86: speculative vulnerability in 32bit SYSCALL path Due to an oversight in the very original Spectre/Meltdown security work (XSA-254), one entrypath performs its speculation-safety actions too late.
In some configurations, there is an unprotected RET instruction which can be attacked with a variety of speculative attacks. (CVE-2022-42331)

- x86 shadow plus log-dirty mode use-after-free In environments where host assisted address translation is necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode.
Shadow mode maintains a pool of memory used for both shadow page tables as well as auxiliary data structures. To migrate or snapshot guests, Xen additionally runs them in so called log-dirty mode. The data structures needed by the log-dirty tracking are part of aformentioned auxiliary data. In order to keep error handling efforts within reasonable bounds, for operations which may require memory allocations shadow mode logic ensures up front that enough memory is available for the worst case requirements.
Unfortunately, while page table memory is properly accounted for on the code path requiring the potential establishing of new shadows, demands by the log-dirty infrastructure were not taken into consideration. As a result, just established shadow page tables could be freed again immediately, while other code is still accessing them on the assumption that they would remain allocated. (CVE-2022-42332)

- x86/HVM pinned cache attributes mis-handling T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To allow cachability control for HVM guests with passed through devices, an interface exists to explicitly override defaults which would otherwise be put in place. While not exposed to the affected guests themselves, the interface specifically exists for domains controlling such guests. This interface may therefore be used by not fully privileged entities, e.g. qemu running deprivileged in Dom0 or qemu running in a so called stub-domain. With this exposure it is an issue that - the number of the such controlled regions was unbounded (CVE-2022-42333), - installation and removal of such regions was not properly serialized (CVE-2022-42334). (CVE-2022-42333, CVE-2022-42334)

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

Solution

Upgrade the xen packages.

For the stable distribution (bullseye), these problems have been fixed in version 4.14.5+94-ge49571868d-1.

Plugin Details

Severity: High

ID: 173415

File Name: debian_DSA-5378.nasl

Version: 1.1

Type: local

Agent: unix

Family: Debian Local Security Checks

Published: 3/26/2023

Updated: 3/28/2023

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2022-42332

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

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

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

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:libxen-dev, p-cpe:/a:debian:debian_linux:libxencall1, p-cpe:/a:debian:debian_linux:libxendevicemodel1, p-cpe:/a:debian:debian_linux:libxenevtchn1, p-cpe:/a:debian:debian_linux:libxenforeignmemory1, p-cpe:/a:debian:debian_linux:libxengnttab1, p-cpe:/a:debian:debian_linux:libxenhypfs1, p-cpe:/a:debian:debian_linux:libxenmisc4.14, p-cpe:/a:debian:debian_linux:libxenstore3.0, p-cpe:/a:debian:debian_linux:libxentoolcore1, p-cpe:/a:debian:debian_linux:libxentoollog1, p-cpe:/a:debian:debian_linux:xen-doc, p-cpe:/a:debian:debian_linux:xen-hypervisor-4.14-amd64, p-cpe:/a:debian:debian_linux:xen-hypervisor-4.14-arm64, p-cpe:/a:debian:debian_linux:xen-hypervisor-4.14-armhf, p-cpe:/a:debian:debian_linux:xen-hypervisor-common, p-cpe:/a:debian:debian_linux:xen-system-amd64, p-cpe:/a:debian:debian_linux:xen-system-arm64, p-cpe:/a:debian:debian_linux:xen-system-armhf, p-cpe:/a:debian:debian_linux:xen-utils-4.14, p-cpe:/a:debian:debian_linux:xen-utils-common, p-cpe:/a:debian:debian_linux:xenstore-utils, cpe:/o:debian:debian_linux:11.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 3/25/2023

Vulnerability Publication Date: 11/8/2022

Reference Information

CVE: CVE-2022-23824, CVE-2022-42331, CVE-2022-42332, CVE-2022-42333, CVE-2022-42334

Detections

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