Flatpak up to 1.14.9/1.15.9 access control

Summaryinfo

A vulnerability was found in Flatpak up to 1.14.9/1.15.9. It has been rated as critical. This impacts an unknown function. Performing a manipulation results in access control. This vulnerability is identified as CVE-2024-42472. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Flatpak up to 1.14.9/1.15.9. This affects an unknown function. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was released by Simon McVittie. The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2024-42472 since 08/02/2024. The exploitability is told to be easy. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 208036 (Oracle Linux 7 : flatpak (ELSA-2024-6417)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.14.10 or 1.15.10 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (208036). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Flatpak

Version

• 1.14.0
• 1.14.1
• 1.14.2
• 1.14.3
• 1.14.4
• 1.14.5
• 1.14.6
• 1.14.7
• 1.14.8
• 1.14.9
• 1.15.0
• 1.15.1
• 1.15.2
• 1.15.3
• 1.15.4
• 1.15.5
• 1.15.6
• 1.15.7
• 1.15.8
• 1.15.9

Website

• Product: https://github.com/flatpak/flatpak/

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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