Be careful. New platforms invite bad actors.

Rooster@infosec.pub to Technology@beehaw.org – 38 points –

Found the error Not allowed to load local resource: file:///etc/passwd while looking at infosec.pub's communities page. There's a community called "ignore me" that adds a few image tags trying to steal your passwd file.

You have to be extremely poorly configured for this to work, but the red flags you see should keep you on your toes for the red flags you don't.

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Is this, by any chance, originated from the sub called ignore? In that case is probably my bad because is set as the image of the channel. (I was playing with lemmy in the previous version and forgot about it, sorry. It will not work since your browser can't access local file that easily without breaking the sandbox :))

Edit: I removed it so you shouldn't see the alert anymore. What I wasn't expecting is that apparently every sub is loaded even if you don't visit it.

/cc @shellsharks@infosec.pub

But... why? Why even put that URL there? Even if it was most likely harmless for all users, this still looks like an attempt at data exfiltration.

Because I wanted to try if others URI schemas were supported instead of http / https. file:// was a valid one. Don't worry, the day an attempt of data exfil will happen, you will not see it though your console logs.

Holy shit this is kind of unsettling. Though I would expect ALL major browsers to reject reading any local files like this..... would this kind of thing actually succeed somewhere/somehow?

If you ran your browser as root and configured your browser to load local resources on non-local domains maybe. I think you can do that in chrome://flags but you have to explicitly list the domains allowed to do it.

I'm hoping this is just a bad joke.

you don't need to be root to read /etc/passwd

Are you sure? What do you get when you run $ cat /etc/passwd in terminal? Just paste the results here 😇

Edit: to anyone reading this on the future, don't actually do this, it was a joke

yup pretty sure

$ cat /etc/passwd
fox:hunter2:1000:1000::/home/fox:/usr/bin/zsh

😉

Yeah, seems highly unlikely to ever yield any results. Even if you did manage to read a file, you have to get lucky finding a password hash in a rainbow table or the password being shit enough to crack.

Also generally the actual password (or rather its hash) is stored in /etc/shadow on most systems from the past 20 odd years.

Nice share, thanks for the information. Definitely need to be careful both as a server operator with Lemmy, and a user of it.

While this is concerning, I wonder what the author(s) of this were thinking would happen. I assume it's supposed to be an attempt at stealing the server's passwords, since I at least know of no browser that freely allows access to local files.

FWIW, /etc/passwd itself contains no passwords (the name exists for historical reasons) but it definitely is a globally accessible file that can give you clues about the target system. Given this, it's more likely the user is attempting to find out if arbitrary disk reads are possible by using a well known path on many servers.