Canonical snapd 16.04 LTS up to 24.04 LTS AppArmor nss-systemd access control

Summaryinfo

A vulnerability labeled as problematic has been found in Canonical snapd 16.04 LTS up to 24.04 LTS. This vulnerability affects unknown code of the file /etc/apparmor.d/abstractions/nss-systemd of the component AppArmor. The manipulation results in access control. This vulnerability is reported as CVE-2024-5300. The attack requires a local approach. No exploit exists.

Detailsinfo

A vulnerability was found in Canonical snapd 16.04 LTS up to 24.04 LTS. It has been classified as problematic. Affected is an unknown part of the file /etc/apparmor.d/abstractions/nss-systemd of the component AppArmor. 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. CVE summarizes:

An access control bypass and information disclosure vulnerability exists in the base AppArmor security profile configuration of Canonical snapd. The abstraction rules located in /etc/apparmor.d/abstractions/nss-systemd (inherited via ) inadvertently permit strictly confined snap applications, which lack the privileged account-control interface, to interact directly with the io.systemd.Multiplexer and io.systemd.NameServiceSwitch UNIX domain sockets under /run/systemd/userdb/. On systems where the systemd-userdbd service is installed and operational, the service fails to distinguish between an unconfined root user on the host system and a restricted root user running within a snap application's sandbox (such as a daemon or configuration hook). Because systemd-userdbd returns "complete" user records—including sensitive hashed user passwords from /etc/shadow—when queried by a process running as root, a compromised or malicious strictly confined snap executing code as root can successfully query the Varlink interface to retrieve all system password hashes, bypassing intended snap sandbox restrictions. This issue is mitigated by the fact that systemd-userdbd is not installed by default on standard Ubuntu deployments.

The advisory is available at ubuntu.com. This vulnerability is traded as CVE-2024-5300 since 05/23/2024. The exploitability is told to be easy. Local access is required to approach this attack. Additional levels of successful authentication are required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• Canonical

Name

• snapd

Version

• 16.04 LTS
• 18.04 LTS
• 20.04 LTS
• 22.04 LTS
• 24.04 LTS
• 26.04 LTS

License

• open-source

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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