CVE-2023-30549
Vulnérabilité élevée dans apptainer (apptainer)
Description
Apptainer is an open source container platform for Linux. There is an ext4 use-after-free flaw that is exploitable through versions of Apptainer < 1.1.0 and installations that include apptainer-suid < 1.1.8 on older operating systems where that CVE has not been patched. That includes Red Hat Enterprise Linux 7, Debian 10 buster (unless the linux-5.10 package is installed), Ubuntu 18.04 bionic and Ubuntu 20.04 focal. Use-after-free flaws in the kernel can be used to attack the kernel for denial of service and potentially for privilege escalation. Apptainer 1.1.8 includes a patch that by default disables mounting of extfs filesystem types in setuid-root mode, while continuing to allow mounting of extfs filesystems in non-setuid "rootless" mode using fuse2fs. Some workarounds are possible. Either do not install apptainer-suid (for versions 1.1.0 through 1.1.7) or set `allow setuid = no` in apptainer.conf. This requires having unprivileged user namespaces enabled and except for apptainer 1.1.x versions will disallow mounting of sif files, extfs files, and squashfs files in addition to other, less significant impacts. (Encrypted sif files are also not supported unprivileged in apptainer 1.1.x.). Alternatively, use the `limit containers` options in apptainer.conf/singularity.conf to limit sif files to trusted users, groups, and/or paths, and set `allow container extfs = no` to disallow mounting of extfs overlay files. The latter option by itself does not disallow mounting of extfs overlay partitions inside SIF files, so that's why the former options are also needed.
Gravité et risque d'exploitation
CVE-2023-30549 obtient un score CVSS de 7.1/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.37 %, ce qui la place devant 29.3 % des CVE référencées.
Que faire ?
- Vérifiez si apptainer (versions < 1.1.8) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://github.com/apptainer/apptainer/security/advisories/GHSA-j4rf-7357-f4cg
- https://github.com/apptainer/apptainer/commit/5a4964f5ba9c8d89a0e353b97f51fd607670a9f7
- https://github.com/torvalds/linux/commit/2220eaf90992c11d888fe771055d4de3303
- https://github.com/torvalds/linux/commit/4f04351888a83e595571de672e0a4a8b74f
- https://access.redhat.com/security/cve/cve-2022-1184
- https://github.com/apptainer/apptainer/releases/tag/v1.1.8
- https://lwn.net/Articles/932136/
- https://lwn.net/Articles/932137/
- https://security-tracker.debian.org/tracker/CVE-2022-1184
- https://sylabs.io/2023/04/response-to-cve-2023-30549/
- https://ubuntu.com/security/CVE-2022-1184
- https://www.suse.com/security/cve/CVE-2022-1184.html
- https://security.gentoo.org/glsa/202311-13