• TheGreatFox@lemmy.dbzer0.comEnglish
    8·
    1 year ago

    Main instance hacked? Time to use an alt!

    The first hack is a rite of passage for every site that gets big. It means we’ve been recognized!

    Luckily, this seems to be a standard troll (with some tech knowledge) - they’ve defaced the site and put redirects to shock sites, rather than injecting actual malware or quietly collecting everyone’s passwords. This could be much worse.

  • Max-P@lemmy.max-p.meEnglish
    7·
    1 year ago

    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.

    • StudioLE@programming.devEnglish
      1·
      1 year ago

      I’m not particularly familiar with XSS but I’m curious how a frontend exploit can compromise an instance?

      Presumably the injected XSS stores the admin’s JWT somewhere for the exploiter?

      Then using that JWT they can effectively login as the admin which gives them access to whatever admin dashboard there is, but does that actually compromise the backend at all?

      edit: for anyone curious there’s a bit of a breakdown of how it works here: https://feddit.win/comment/244427

      • CMahaff@lemmy.mlEnglish
        2·
        1 year ago
        1. Inject exploit into a comment using custom emoji.
        2. Front-end parses the emoji incorrectly allowing JavaScript to be injected.
        3. JavaScript loads for everyone to views a page with the comment and sends their token and account type to the hackers domain.
        4. Hacker parses received tokens for admins and uses that to inject redirects into the front page of the Lemmy instance.

        To answer your other questions:

        • IMO there probably should be better parsing to remove this stuff from the back-end, so I’m not sure the front-end solution is the complete solution, but it should get things largely under control.
        • Back-end is theoretically not compromised besides needing to purge all the rogue comments. Attacker presumably never had access to the server itself.
        • Probably needs to be a mass reset of ALL passwords since lots of people’s tokens were sent during the attack, so their accounts could be compromised.
    • Kayn@dormi.zoneEnglish
      0·
      1 year ago

      But won’t custom emojis from remote instances still trigger the exploit?

      • ruk_n_rul@monyet.ccEnglish
        01·
        1 year ago

        Apparently the custom emojis are rendered as static images when federated to outside instances so it’s clean.

  • Max-P@lemmy.max-p.meEnglish
    3·
    1 year ago

    I tried to reproduce the exploit on my own instance and it appears that the official Docker for 0.18.1 is not vulnerable to it.

    It appears that the malicious code was injected as an onload property in the markdown for taglines. I tried to reproduce in taglines, instance info, in a post with no luck: it always gets escaped properly in the <img alt="exploit here"> property as HTML entity.

    lemmy.world appears to be running a git commit that is not public.

    • CMahaff@lemmy.mlEnglish
      3·
      1 year ago

      I actually consider it good news that the redirection is happening this way (something that can be done just by having the lemmy credentials of an admin) vs something indicating they have access to the server itself.

      • maegul (he/they)@lemmy.mlEnglish
        2·
        1 year ago

        Yep, same. It was also the most likely scenario.

        It looks like it was an individual admin getting hacked. Not good but not the worst. Most fallout will probably be whether their security practices were sufficient for an admin and whether lemmy has good enough contingencies for this sort of thing. Lemmy’s 2FA is probably a hot issue now though.

        • RoundSparrow@lemmy.mlEnglish
          2·
          1 year ago

          The JWT are likely a hot issue, already some Issues on GitHub about them not being revoked properly.

          • CMahaff@lemmy.mlEnglish
            1·
            1 year ago

            Oh man, that would be brutal if they are resetting the password and it isn’t kicking the attacker out…

            • Max-P@lemmy.max-p.meEnglish
              1·
              1 year ago

              That’s probably what happened here because they did revoke the admin’s access, but it continued.

        • Rentlar@lemmy.caEnglish
          1·
          1 year ago

          OK good to know that the server itself is unlikely to be compromised. I’ll be changing passwords to all my accounts once this blows over.

          • darrsil@beehaw.orgEnglish
            2·
            1 year ago

            Yeah, the Lemmy 2FA implementation sucks. It only works in certain authenticators - Authy not being one of them. Google Authenticator does work and apparently so does the iOS keychain (but can’t confirm that one).

            Best way to do it is to enable it and set it up but keep the settings window open, then open a separate incognito window and try to log in. If your 2FA code doesn’t work, go back to the other settings window and disable it.

        • G59@lemmy.mlOPEnglish
          1·
          1 year ago

          The hacked MichelleG account actually commented that it did not have MFA enabled lol. This was on the lemmy.world shitpost community, on one of the posts making memes about the situation. Hilarious that the hacker decided to share that.

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

      It seems the database and the server itself is not compromised? Just an admin account that used to post a markdown XSS exploit?

      • Max-P@lemmy.max-p.meEnglish
        1·
        1 year ago

        Pretty much, and it’s not even XSS (it’s not cross-site), it’s just plain basic HTML injection breaking out of Markdown. At least as far as I was able to find.

    • tarjeezy@lemmy.caEnglish
      0·
      1 year ago

      Last I saw, they were on 0.18.1, unless a very recent update was installed. Do you happen to have a full list of domains they were redirecting to? Just want to be sure they were only going to “harmless” offensive sites, and not something worse.

      • Max-P@lemmy.max-p.meEnglish
        1·
        1 year ago

        As for the version, my instance reports it as

        0.18.1-2-ga6cc12afe

        So it seems to be using some extra patches, but I can’t find that commit on GitHub which indicates it might not be public, or cherry-picked locally.

        So with this in mind, either it’s just innocent performance patches, or someone potentially also introduced the markdown vulnerability.

        Although it’s also entirely possible I suck and wasn’t able to reproduce it correctly/had wrong quoting or something. Hopefully the devs can shine some light in the details.

      • Max-P@lemmy.max-p.meEnglish
        1·
        1 year ago

        Only lemonparty (which then redirects to chaturbate) and the pedo image hosted in the pictrs of lemmy.world itself. I saw no evidence of anything else, as people said, it’s a pretty oldschool type of hack to disturb not spread malware.

        But I didn’t dig that much further than that, and it’s only a snapshot of what I gathered before it got fixed. I Ctrl+F “lemonparty” in view source and pasted the JSON in VScode and that’s about it. Didn’t dig much deeper if that was just a red herring.

  • Candelestine@lemmy.caEnglish
    3·
    1 year ago

    Yea, I switched to this alt. It appears to be one of the assistant admins accts. Seems like an old fashioned anon prank, to me, they’re mainly just trying to make stuff offensive and redirect people to lemonparty.

    So, y’know, old school.

    I don’t know if any data is actually in danger, but I doubt it. I don’t see why assistant admins would need access to it.

    • hawkwind@lemmy.managementEnglish
      4·
      1 year ago

      All the bean memes are in danger! On a serious note, old-skool or not, it’s a huge loss of trust in something the community-at-large is excited to see replace reddit.

      • Candelestine@lemmy.caEnglish
        6·
        1 year ago

        Par for the course. This system will never be immune to things like that. That’s part of what happens when you decentralize your power. Instead of a single target that can be made highly secure, you have a distributed array of targets.

        People should certainly be engaging on here with full awareness of the reality of the Fediverse, not expecting reddit 2.0. We never will be able to offer exactly what they did. We’ll be naturally worse in some areas and naturally better in others.

        • Philolurker@lemm.eeEnglish
          5·
          1 year ago

          This is why I’m glad I made redundant accounts on multiple instances. When there are problems on lemmy.world, I can just hop on over to another. That’s never been an option with Reddit.

          Now if there was only a way to export or sync user settings like subscriptions, it would be perfect.

        • hawkwind@lemmy.managementEnglish
          1·
          1 year ago

          True that. If you look at posts on lemmy.world though, it’s clear their users (which is like 50% of Lemmy) have zero clue they’re defederated ATM, and probably many that don’t know it’s compromised.

          • Hexadecimalkink@lemmy.mlEnglish
            02·
            1 year ago

            Federation and decentralization are not Web 2.0 concepts. Just like people who first learned what a tweet and a follow were and all the other concepts of those social media platforms, they’ll learn the new paradigm. Or they won’t and we’ll stick to 2.0 platforms.

      • Menachem@midwest.socialEnglish
        1·
        1 year ago

        idk, im surprised it took this long. there’s a huge variety of admin teams with varying degrees of security awareness and it’s been over a month since the first big influx of users started. it’ll happen again too and probably not before too long

        • Lenins2ndCat@lemmy.mlEnglish
          1·
          1 year ago

          In the 3 years Hexbear has been around it has been attacked A LOT because obviously far right chuds have an interest in messing with leftists but has not to my knowledge had an admin breach. At one point image embeds were completely disabled because they were handing over data they shouldn’t though and risked exposing people to doxxing.

    • CMahaff@lemmy.mlEnglish
      2·
      1 year ago

      My concern is that configuring the site to automatically redirect users sounds like they have pretty large control over the site - the kind of control that I would assume is usually limited to users with root access on the server.

      Obviously hope nothing of value is lost and that there is a proper off-site backup of the content.

      Edit: See Max-P’s comment, it looks like the site redirection was accomplished in a way that IMO suggests they do NOT have full control over the site. We’ll obviously have to wait for the full debrief from the admins.

      • thanks_shakey_snake@lemmy.caEnglish
        1·
        1 year ago

        Yeah the “redirect somewhere else” attack definitely doesn’t necessarily require any particular control of the site. Usually it’s noticing that you can trick some text into being run as Javascript, instead of interpreted as text… And then you just stick in a cheeky little <notarealscript>window.location = "https://www.badsite.horse"</notarealscript> into that spot.

        Then every time that comment, username, (in this case apparently) custom emoji, etc. gets loaded, whoops, the code runs and off you go!

        So no control of the site is required at all.

      • JackbyDev@programming.devEnglish
        0·
        1 year ago

        If it was just DNS that doesn’t mean too much. If it was just DNS it seems to be back up. It’s like changing the number in a phone book.

  • upt@lemmy.ml
    2·
    1 year ago

    Being a part of Lemmy in these early days has been kind of interesting, seeing all of the bugs and bits that will be ironed out over time. One day when Lemmy is as old as Reddit it will all be folklore. Maybe.

  • maegul (he/they)@lemmy.ml
    2·
    1 year ago

    Hmmm. Don’t know what the fall out of this will be. But a lot of lemmy is on that server. Unfortunately. Maybe we’ll learn a lesson in the value of decentralisation.

    Ruud also runs mastodon.world, FYI.

    • Lemon@lemmy.blahaj.zoneEnglish
      2·
      1 year ago

      This is why it makes sense for communities to not all pile into one instance, it gives one instance admin too much power and responsibility over everything.

    • Stovetop@lemmy.mlEnglish
      1·
      1 year ago

      One of the admin accounts appears to have been compromised. The owner/other admins appear to be aware now because that account had its admin access revoked and offending posts are being removed.

      Definitely opens up a big question about the security of Lemmy instances that I am sure will be discussed over the next few days.

      • eerongal@ttrpg.networkEnglish
        0·
        1 year ago

        Definitely opens up a big question about the security of Lemmy instances that I am sure will be discussed over the next few days.

        They added 2FA login to lemmy in one of the newer updates. Probably pretty pertinent for any admins to use it…

        • ebits21@lemmy.caEnglish
          1·
          1 year ago

          It’s buggy and missing some key checks to make sure it’s working when you set it up.

          Real risk of locking yourself out of your account.

            • ebits21@lemmy.caEnglish
              0·
              1 year ago

              Mostly a risk on initial setup.

              I’ve been waiting a bit for it to stabilize and just using huge random passwords

              • Zetaphor@zemmy.ccEnglish
                0·
                1 year ago

                If you’re using a password manager you’d be doing this for every site and without even having to think about it. Bitwarden is a great choice.

                • The Cuuuuube@beehaw.orgEnglish
                  0·
                  1 year ago

                  I like KeePass. Bitwarden currently has an nginx exposure in the Dockerfile published in their git repo (may have been fixed since a couple of days ago). That said, I used Bitwarden for many years and switched out of an abundance of paranoia, and am definitively not recommending against it. Just basically use one of the following:

                  • Bitwarden
                  • KeePass
                  • 1password

                  And stay far the fuck away from LastPass

    • Max-P@lemmy.max-p.meEnglish
      1·
      1 year ago

      Not a whole lot - you might see some spam being federated from lemmy.world but I’d expect the lemmy.ml and lemmy.world admins will fix it, and them clean it up.

      That’s probably good stress test to figure out how to handle that.

    • Stovetop@lemmy.ml
      2·
      1 year ago

      It looks like they’re in the process. The compromised account was demoted from admin and I see posts are being removed. There will definitely need to be some sort of investigation into how this happened, though.