Apologies if this is a rookie question, but I keep wondering what the vulnerabilities section on DockerHub is trying to tell me. Take nextcloud images for instance: The most current images seem to list 3 critical and 22 severe vulnerabilities. Does that mean those vulns are part of the image? If so, why would anyone want to run this?
Those vulnerabilities are inherited from the Debian base image. Debian is extremely diligent about fixing high-risk vulnerabilities. A high severity CVE does not automatically mean that you are at severe risk. It’s more an indication of how fucked you can be IF the vulnerability is exploited to its greatest potential.
One of the CVEs affects libraw, which is a library for handling RAW photograph files. If a RAW file contains a particular header, and that header is maliciously constructed in a particular way, extracting an embedded thumbnail can allow the attacker to execute arbitrary code on the server. To make that happen, the attacker must either gain access to a device (e.g. camera) you own, or already have access to the server to upload and process the file, which means that security has already failed.
The Swiss cheese model applies to cybersecurity too.
Thanks for your detailed reply!
Do I correctly assume that by axis you mean shell or even root level access? If not, any of my regular users (turned rogue…) could upload a poisoned raw file which nextcloud would process to, for instance, generate a thumbnail.
I mean whatever level of access is required to upload an image. That can be access to the web app (with login), access through WebDAV, or access to the underlying OS or filesystem. If you can put a file on Nextcloud, it is sufficient access.
I forgot to mention that the vulnerability can only be exploited if libraw is also compiled with a particular flag that enables the vulnerable feature. That flag is disabled on base Debian. Docker’s service doesn’t test whether the vulnerability is actually present in the image, only that the package version is listed as affected.