As I noted within my post #9955859@lemm.ee (alternate link), I found that thumbnail generation in Element is an enourmous privacy, and security vulnerability. Thumbnails are generated server-side, regardless of E2EE settings. What this means is that the URLs that one sends would be leaked out of your encrypted chats to the server.
That doesn’t make any sense… If the URLs are server side that means there is no e2ee at any time because the server has to know when to shown the preview…
If that’s true disabling preview generation doesn’t really matter because the vulnerability would be elsewhere
I never used matrix, but do clients own the keys or are they stored on the server?
If you look at this documentation it outlines various methods of generating URL thumbnails. Essentially, a separate request from the client for only the URL is made to the server which then returns a thumbnail. It’s an absolutely moronic design choice, if you ask me.
I agree. That’s a terrible choice to me.
Why would they not just offload this as a feature for the client to handle? At least then the security and privacy ultimately would be up to the user’s decision.
Post a link to a channel of 1k users and 1k users send a request to the website, instead of only the server once?
/edit: From a privacy standpoint I’d really trust my chat server provider over random websites. So I definitely don’t see how it’s a terrible choice for these two reasons.
That being said, if you’re concerned, disabling previews is the answer.
Have you posted a suggestion on github? I feel like this was a proof on concept during development and maybe it was forgotten about further along the life cycle.
There are existing issues on GitHub: