Drawing attention on this instance so Admins are aware and can address the propagating exploit.
EDIT: Found more info about the patch.
A more thorough recap of the issue.
GitHub PR fixing the bug: https://github.com/LemmyNet/lemmy-ui/pull/1897/files
If your instance has custom emojis defined, this is exploitable everywhere Markdown is available. It is NOT restricted to admins, but can be used to steal an admin’s JWT, which then lets the attacker get into that admin’s account which can then spread the exploit further by putting it somewhere where it’s rendered on every single page and then deface the site.
If your instance doesn’t have any custom emojis, you are safe, the exploit requires custom emojis to trigger the bad code branch.
Alright, so what do they plan to do? Compromise Lemmy, sure. Then what? What do they gain? Propaganda?
Basically pull data on various accounts (IP address, activity history, etc), people, and trends. They could promote given posts or suppress posts or hide things from moderators. They could distribute whatever malware they might like, target specific accounts that way…
The possibilities are many.
Even so, it just seems like a lot of work and risk for something that would not be necessary to achieve those or similar goals. Besides, if word gets out that the software is compromised, then people will just stop using it. The much better/easier solution would be run scams, vote manipulation, etc as it doesn’t kill your platform that you would then be using to push a goal or agenda.
The name of the game is to not be noticed. You have a bad user or instance, they get banned and make a new one. Compromising the whole thing though? That’s one and done, especially where the Lemmy croud is a lot more tech oriented than most other platforms.
My point being that why compromise Lemmy for a short while then have it die vs playing the long game and have an ever increasing user base to scam, steal from or manipulate? It just doesn’t make sense when you think about it.
