TencentOS Server 2: flatpak (TSSA-2024:0502)

high Nessus Plugin ID 239791

Synopsis

The remote TencentOS Server 2 host is missing one or more security updates.

Description

The version of Tencent Linux installed on the remote TencentOS Server 2 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2024:0502 advisory.

Package updates are available for TencentOS Server 2 that fix the following vulnerabilities:

CVE-2024-42472:
Flatpak is a Linux application sandboxing and distribution framework. Prior to versions 1.14.0 and 1.15.10, a malicious or compromised Flatpak app using persistent directories could access and write files outside of what it would otherwise have access to, which is an attack on integrity and confidentiality.

When persistent=subdir is used in the application permissions (represented as --persist=subdir in the command-line interface), that means that an application which otherwise doesn't have access to the real user home directory will see an empty home directory with a writeable subdirectory subdir. Behind the scenes, this directory is actually a bind mount and the data is stored in the per-application directory as ~/.var/app/$APPID/subdir. This allows existing apps that are not aware of the per-application directory to still work as intended without general home directory access.

However, the application does have write access to the application directory ~/.var/app/$APPID where this directory is stored. If the source directory for the persistent/--persist option is replaced by a symlink, then the next time the application is started, the bind mount will follow the symlink and mount whatever it points to into the sandbox.

Partial protection against this vulnerability can be provided by patching Flatpak using the patches in commits ceec2ffc and 98f79773. However, this leaves a race condition that could be exploited by two instances of a malicious app running in parallel. Closing the race condition requires updating or patching the version of bubblewrap that is used by Flatpak to add the new --bind-fd option using the patch and then patching Flatpak to use it. If Flatpak has been configured at build-time with -Dsystem_bubblewrap=bwrap (1.15.x) or --with-system-bubblewrap=bwrap (1.14.x or older), or a similar option, then the version of bubblewrap that needs to be patched is a system copy that is distributed separately, typically /usr/bin/bwrap. This configuration is the one that is typically used in Linux distributions. If Flatpak has been configured at build-time with -Dsystem_bubblewrap= (1.15.x) or with --without-system-bubblewrap (1.14.x or older), then it is the bundled version of bubblewrap that is included with Flatpak that must be patched. This is typically installed as /usr/libexec/flatpak-bwrap. This configuration is the default when building from source code.

For the 1.14.x stable branch, these changes are included in Flatpak 1.14.10. The bundled version of bubblewrap included in this release has been updated to 0.6.3. For the 1.15.x development branch, these changes are included in Flatpak 1.15.10. The bundled version of bubblewrap in this release is a Meson wrap subproject, which has been updated to 0.10.0. The 1.12.x and 1.10.x branches will not be updated for this vulnerability. Long-term support OS distributions should backport the individual changes into their versions of Flatpak and bubblewrap, or update to newer versions if their stability policy allows it.
As a workaround, avoid using applications using the persistent (--persist) permission.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

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

Solution

Update the affected packages.

Plugin Details

Severity: High

ID: 239791

File Name: tencentos_TSSA_2024_0502.nasl

Version: 1.1

Type: local

Family: Tencent Local Security Checks

Published: 6/16/2025

Updated: 6/16/2025

Supported Sensors: Nessus

Vulnerability Information

CPE: cpe:/o:tencent:tencentos_server:2, p-cpe:/a:tencent:tencentos_server:flatpak

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/etc/os-release, Host/TencentOS/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 9/5/2024

Vulnerability Publication Date: 9/5/2024

Detections

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