CVE-2024-29068

In snapd versions prior to 2.62, snapd failed to properly check the file type when extracting a snap. The snap format is a squashfs file-system image and so can contain files that are non-regular files (such as pipes or sockets etc). Various file entries within the snap squashfs image (such as icons etc) are directly read by snapd when it is extracted. An attacker who could convince a user to install a malicious snap which contained non-regular files at these paths could then cause snapd to block indefinitely trying to read from such files and cause a denial of service.

In snapd versions prior to 2.62, snapd failed to properly check the file type when extracting a snap. The snap format is a squashfs file-system image and so can contain files that are non-regular files (such as pipes or sockets etc). Various file entries within the snap squashfs image (such as icons etc) are directly read by snapd when it is extracted. An attacker who could convince a user to install a malicious snap which contained non-regular files at these paths could then cause snapd to block indefinitely trying to read from such files and cause a denial of service.

snapd failed to properly check the file type when extracting a snap in github.com/snapcore/snapd.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: github.com/snapcore/snapd before v2.62.0.

Neil McPhail discovered that snapd did not properly restrict writes to the $HOME/bin path in the AppArmor profile for snaps using the home plug. An attacker who could convince a user to install a malicious snap could use this vulnerability to escape the snap sandbox. (CVE-2024-1724)

Zeyad Gouda discovered that snapd failed to properly check the file type when extracting a snap. An attacker who could convince a user to install a malicious snap containing non-regular files could then cause snapd to block indefinitely while trying to read from such files and cause a denial of service. (CVE-2024-29068)

Zeyad Gouda discovered that snapd failed to properly check the destination of symbolic links when extracting a snap. An attacker who could convince a user to install a malicious snap containing crafted symbolic links could then cause snapd to write out the contents of the symbolic link destination into a world-readable directory. This in-turn could allow a local unprivileged user to gain access to privileged information. (CVE-2024-29069)

USN-6940-1 fixed vulnerabilities in snapd. This update provides the corresponding updates for Ubuntu 18.04 LTS and Ubuntu 16.04 LTS.

Original advisory details:

Neil McPhail discovered that snapd did not properly restrict writes to the /home/jslarraz/bin path in the AppArmor profile for snaps using the home plug. An attacker who could convince a user to install a malicious snap could use this vulnerability to escape the snap sandbox. (CVE-2024-1724)

Zeyad Gouda discovered that snapd failed to properly check the file type when extracting a snap. An attacker who could convince a user to install a malicious snap containing non-regular files could then cause snapd to block indefinitely while trying to read from such files and cause a denial of service. (CVE-2024-29068)

Zeyad Gouda discovered that snapd failed to properly check the destination of symbolic links when extracting a snap. An attacker who could convince a user to install a malicious snap containing crafted symbolic links could then cause snapd to write out the contents of the symbolic link destination into a world-readable directory. This in-turn could allow a local unprivileged user to gain access to privileged information. (CVE-2024-29069)