Alpine: xen: security update to 4.15.5-r3

high Tenable Cloud Security Plugin ID 407827

Description

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

- The caching invalidation guidelines from the AMD-Vi specification (48882—Rev 3.07-PUB—Oct 2022) is
incorrect on some hardware, as devices will malfunction (see stale DMA mappings) if some fields of the DTE
are updated but the IOMMU TLB is not flushed. Such stale DMA mappings can point to memory ranges not owned
by the guest, thus allowing access to unindented memory regions. (CVE-2023-34326)

- When a transaction is committed, C Xenstored will first check the quota is correct before attempting to
commit any nodes. It would be possible that accounting is temporarily negative if a node has been removed
outside of the transaction. Unfortunately, some versions of C Xenstored are assuming that the quota cannot
be negative and are using assert() to confirm it. This will lead to C Xenstored crash when tools are built
without -DNDEBUG (this is the default). (CVE-2023-34323)

- [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities
correspond to which CVE.] libfsimage contains parsing code for several filesystems, most of them based on
grub-legacy code. libfsimage is used by pygrub to inspect guest disks. Pygrub runs as the same user as the
toolstack (root in a priviledged domain). At least one issue has been reported to the Xen Security Team
that allows an attacker to trigger a stack buffer overflow in libfsimage. After further analisys the Xen
Security Team is no longer confident in the suitability of libfsimage when run against guest controlled
input with super user priviledges. In order to not affect current deployments that rely on pygrub patches
are provided in the resolution section of the advisory that allow running pygrub in deprivileged mode.
CVE-2023-4949 refers to the original issue in the upstream grub project ("An attacker with local access to
a system (either through a disk or external drive) can present a modified XFS partition to grub-legacy in
such a way to exploit a memory corruption in grub’s XFS file system implementation.") CVE-2023-34325
refers specifically to the vulnerabilities in Xen's copy of libfsimage, which is decended from a very old
version of grub. (CVE-2023-34325)

- [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities
correspond to which CVE.] AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen
supports guests using these extensions. Unfortunately there are errors in Xen's handling of the guest
state, leading to denials of service. 1) CVE-2023-34327 - An HVM vCPU can end up operating in the context
of a previous vCPUs debug mask state. 2) CVE-2023-34328 - A PV vCPU can place a breakpoint over the live
GDT. This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock up the CPU entirely.
(CVE-2023-34327)

Plugin Details

Severity: High

ID: 407827

Version: Revision 1.29

Type: Local

Family: Alpine Linux Local Security Checks

Published: 10/31/2023

Updated: 7/2/2026

Supported Sensors: Agentless Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.12

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-2023-34326

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 10/11/2023

Reference Information

CVE: CVE-2023-34323, CVE-2023-34325, CVE-2023-34326, CVE-2023-34327, CVE-2023-34328, CVE-2023-46835, CVE-2023-46836

IAVB: 2023-B-0081-S, 2023-B-0090-S

Detections

Analytics