cross-posted from: https://sh.itjust.works/post/923025

lemmy.world is a victim of an XSS attack right now and the hacker simply injected a JavaScript redirection into the sidebar.

It appears the Lemmy backend does not escape HTML in the main sidebar. Not sure if this is also true for community sidebars.

  • Thelsim
    5•1 year ago

    So, as an average, less-technical, Lemmy user (this is my backup for now).
    What can or should I do to stay safe?

    • @theneverfox
      4•1 year ago

      Id use an app you trust for now

      On a site you have to sanitize your data, on a native app you’d have to go out of your way to render this kind of thing…wefwef/voyager is actually a web page (and they might or might not be sanitizing their inputs), the other top options are probably using libraries to do it, and data sanitation is pretty basic. Literally web dev 101. They’d have to choose a very full-featured rendering library that also entirely ignores security, or they’d have to have rolled their own

      At least now I know why my renderer has been so annoying about the warnings the last couple days…

      For any devs that read this - this is a great example of why you can’t trust anything coming off a federated network. Type check and sanitize all your inputs, always. We need to get away from trust - this isn’t a trustful situation

      Luckily, this was more of a warning than an actual attack - and there will be actual attacks. We have to be defensive - always - every time at every level.

      And Flemmy will be that, once I feel good releasing it (2 features left before I’m out of reasons to procrastinate). It’ll be just me, always