Hi all,

If you’re just now signing in for the first time in 12+ hours, you may just now be finding out that Lemmy World and other instances where hijacked. The hijackers had the full abilities of hijacked user, mod, and admin accounts. At this time, I am only aware of instance defacing and URL redirections to have been done by the hijackers.

If you were not forced to sign back in this morning, contact your instance admin to verify mitigations were completed on your instance.

How?

This occurred due to an XSS attack in the recently added custom emojis. Instance admins should follow the issue tracker on the LemmyNet GitHub, as well as the Matrix Chat. Post-Incident Activity is still on-going.

Currently, it is likely that just your session cookie was stolen, with instance admins being targeted specifically by checking for navAdmin, an HTML element only instance admins had. I do not believe this to affect users across instances, but I have yet to confirm this.

What happens next?

As I am not the developers or affected instance admins, I cannot make any guarantees. However, here is what you’ll likely see:

  1. Post Incident investigation continues. This will include inspecting code, posts, websites, and more used by the hijackers. An official incident writeup may occur. You should expect the following from that report:
  • Exactly what happened, when.
  • The incident response that occurred from instance admins
  • Information that might have helped resolve the issue sooner
  • Any issues that prevented successful resolution
  • What should have been done differently by admins
  • What should be improved by developers
  • What can be used to identify the next attack
  • What tools are needed to identify that information

  1. A CVE is created. This is an official alert of the issue, and notifies security experts (and enthusiasts), even those not using lemmy, about the issue.

  2. A code security audit is done. This will likely just be casual reviews by technical lemmy users. However, I will be reaching out to the Mozilla Foundation and Cure53 as they recently did an audit of Mastodon. If there is interest in an external audit of lemmy and the costs are affordable, I’ll look into crowdfunding this cost.

  • Notorious@lemm.eeEnglish
    201·
    1 year ago

    Lemmy decided to go with SHA256 for TOTP seed. This is a very odd move since many 2FA apps don’t support SHA256. I actually had to write a quick python script to spit out my 2FA code since Bitwarden doesn’t support it. Hopefully either Lemmy will change to SHA-1 or Bitwarden will start to support SHA256 seeds.

      • subtext@lemmy.worldEnglish
        3·
        1 year ago

        Bitwarden definitely works with SHA256 and even SHA512, I believe. And with codes longer than 6 digits also. Oh and even Steam codes if you really want.

      • Trapping5341@lemmy.worldEnglish
        2·
        1 year ago

        wait wait wait. how did you get lemmy 2FA into bitwarden. I can only get it to set up in authy or google auth

        • redcalcium@c.calciumlabs.comEnglish
          2·
          1 year ago

          You’ll need to either subscribe to bitwarden premium ($10 / year), or deploy vaultwarden in your own server and have your bitwarden extension/app use that vaultwarden server instead of the official server.

          • Trapping5341@lemmy.worldEnglish
            1·
            1 year ago

            Yeah I have premium and every account I have that offers 2fa is set up but Lemmy will only let me set it up in authy or Google auth. It won’t give bitwarden as an option or give me the code to manually add it to bitwarden.

            • redcalcium@c.calciumlabs.comEnglish
              2·
              1 year ago

              Just right click at the 2fa button and select “copy link”, then paste the link into bitwarden TOTP field. The link you copied should already be in the format otpauth://totp/xxxx which will be recognized by bitwarden.

      • subtext@lemmy.worldEnglish
        2·
        1 year ago

        Doesn’t matter too too much for a TOTP though. It just needs to be pseudorandom enough for a relatively difficult to guess 6 digit (or longer) code that changes every 30 seconds. Much more likely for someone to get phished for their TOTP than for someone to reverse engineer someone’s TOTP seed. Plus how would that even happen? The attacker would need to have the device and / or track the user’s 6 digit codes for quite a while at which point the game’s already up.