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Last night, lemmy.world was compromised via an XSS vulnerability with custom emoji. Using this vulnerability, attackers took control of an admin account. The site redirected to mp4 files when logged in, and porn sites when not logged in. The issue was resolved by lemmy.world admins soon after it started, but the attacker regained control of the compromised admin account around ten minutes after resolution, redirecting users to the same mp4 files and sites. Soon after that, the site became inaccessable. The issue is currently resolved, and lemmy dev team has been notified of this vulnerability. sh.itjust.works will not be affected, as we do not have any custom emojis. If you own an instance with custom emojis, it is advised to remove these emojis and clear your cookies.

The following is the original post:

PSA: DO NOT ATTEMPT TO ACCESS LEMMY.WORLD, THERE MIGHT BE MALWARE

Lemmy.world member here. I created this account after .world started redirecting me to porn sites and odd mp4 files. We might want to defederate to limit the potential impact. Also, SJW might be affected by the same vulnerabilities as .world, so maybe the admins here should look at that.

Edit: Situation seems to have stabilized. Some site icons aren’t loading, but otherwise everything seems stable. Read Edit2

Edit2: HOLY SHIT ITS BACK Read Edit3

Edit3: lemmy.world is now down as of 10:56 PM CST (USA) Read Edit4

Edit4: lemmy.world is now up, but serving an error as of 11:03 CST (USA) See a screenshot of this error. I also got logged out, hopefully it doesn’t mean they just wiped the databases lol.

Edit5: Edit4 still applies, but I can now access lemmy.world via Memmy on my phone. Wefwef (Voyager now) does not work, however. Timestamp: 11:34 PM CST (USA)

Edit6: lemmy.world restored. Compromised admin account said something in a weird post. I’m going to bed now, my brain is play-dough rn. Will update you guys tomorrow morning.

  • 🍹Early to RISA 🧉@sh.itjust.worksEnglish
    67·
    1 year ago

    Talk about feeling like the old internet. I was wondering how I would get tricked into seeing something gross by some shock-humor edgelord.

    Time to just grab a pint and wait this out. Lol

  • Givesomefucks@reddthat.comEnglish
    59·
    1 year ago

    What impact?

    As long as you dont go on lemmy.world, it’s not going to redirect you to all the stupid websites.

    And I doubt whatever they’re posting (if they’re posting anything) is getting upvoted, so you won’t see it anywhere else.

    And where are you getting “malware” from?

    People are acting like it’s some crazy hack, and not the 4chan rejects from exploding heads finally guessing an admins password a week after they got defederated. And after all that time chasing the mailman, they had no idea what to do when they guessed it

    But this does highlight an issue with instances. I doubt the handful of admins know each other. Like, maybe an email, but for the most part if shit like this happens during “off hours” it might be a while before the top admin even knows there’s an issue

    • SimplePhysics@sh.itjust.worksOPEnglish
      24·
      1 year ago

      Did you read my post? -I said there might be malware. -I said not to visit lemmy.world -The entire site may be fucking compromised. If you have control the servers, you can change database values to make your post any amount of upvotes you want.

      • hemmesEnglish
        2·
        1 year ago

        Now let’s see if this goes the way VLemmy did this weekend.

          • hemmesEnglish
            7·
            1 year ago

            Out of nowhere the instance went down. I believe it was late Saturday morning or so? It was my main instance and nobody has heard from the admin. He was always very enthusiastic and transparent, actively looking for more admins.

            A day or so before it went down, he made a post about having to defederate with another instance due to current violation laws in his server’s country of origin. VLemmy is known for not banning many (if any) instances in favor of moderation, so they take defederation very seriously.

            It looks like he got caught up with some bad content and had to shutdown. Not sure how long but all his tip and donation links have been closed including I believe his GitHub.

    • Mic_Check_One_Two@reddthat.comEnglish
      18·
      1 year ago

      Seems like there’s an active cookie-scraping attack going on. Lots of compromised accounts are going around different instances posting links with drive-by JavaScript. The JS tries to grab your current login token, which would give hackers access to your current login session.

      They don’t need your password because they’re just grabbing that cookie that your browser gets when you check the “Keep me logged in” checkbox on login. That’s what allows you to verify your account across multiple sessions, and it allows them to do the exact same thing. They can simply send that authorized token, and “log in” as you. This would (likely) work across instances, because if they grab your cookie then it will give them access to whatever instance your account is logged in on.

      So Lemmy.world will likely need to be completely defederated (to stop any compromised accounts from posting on other instances) and your specific instance will likely need to deauthorize all current login tokens (which will forcibly log everyone on your instance out) to stop any local accounts that got hit.

      • Givesomefucks@reddthat.comEnglish
        13·
        1 year ago

        And how many people answer that on Sunday night?

        What I’m getting at is a major website has at least a skeleton staff that can do something, even if that’s just pulling the plug.

        I don’t even reply to most work texts after hours unless it’s someone saying they have to use sick leave. I don’t expect people hosting Lemmy as a hobby to be on call 24/7.

        But I hope afterwards they’re transparent about what happened and how they’re going to stop it from happening again. If not, it’s easy to hop instances

    • bestdude@kbin.social
      4·
      1 year ago

      Could I get hacked or compromised or something just by lurking the website? I didn’t notice the Israel stuff until a bit late
      Password was randomly generated like 5f.4_0@3j&j so no common passwords

  • TheDude@sh.itjust.worksMEnglish
    56·
    1 year ago

    The vulnerability appeared to be from a custom emoji that they were running. SJW does not use any custom emoji so we should not be affected. In either case lemmy.world has now been restored and is back online. I’ll keep an extra eye on this instance until the patch gets released shortly.

  • BitingChaos@kbin.social
    25·
    1 year ago

    Well, on the bright side of things, I’m able to find out about my main server going down from the dozens of other active instances.

    • SimplePhysics@sh.itjust.worksOPEnglish
      8·
      1 year ago

      Damn. SJW and .world share the same lemmy source code. Could what is happening to .world happen to SJW? I’d take a dig into the lemmy code, but my brain is literal mush right now, its 11:16 PM here.

      • TWeaK@lemm.eeEnglish
        9·
        1 year ago

        Potentially. Apparently it’s spreading through comments, not just the sidebar.

  • Ziggurat@sh.itjust.worksEnglish
    16·
    1 year ago

    What’s the impact for other instance users ?

    None ? lemmy.world was down during the night and is fixed this morning that’s it ?

    is there a risk that interaction with lemmy.world are leaked including potential “personal data” ?

    is there a risk that smarter hackers could use the breach to access the DB behind some lemmy instances without anybody noticing it ?

    • SimplePhysics@sh.itjust.worksOPEnglish
      4·
      1 year ago

      Lemmy.world was defaced last night. As far as I know, there is no DB breach. An XSS vulnerability was abused to steal the cookies of an admin account.

  • AndreTelevise@kbin.social
    9·
    1 year ago

    And I have nowhere to go but Kbin because Beehaw is unstable and I don’t want to open up a fourth account. Accumulating fediverse accounts should be the last thing you do

  • ChronicEd@kbin.social
    8·
    1 year ago

    About 10:38 pm CST I had just opened it on my browser and it flashed a “Reddit has taken over this site for copyright infringement”. And the icon at the top was changed for Israel with the words about raping a child on it. Definitely something wonky going on, but I haven’t seen any redirects to anything off site. Definitely not going back from my computer (sounds like the app is safe, but only will check for an update).

    • SimplePhysics@sh.itjust.worksOPEnglish
      5·
      1 year ago

      Yeah, I get that too, minus the Reddit part. However, during the ten minute span where the attack was resolved (then restarted), a mod/admin account reported that it was caused by a compromised admin account, so not Reddit taking over the site via copyright law. They removed the account, but the issue seems to be back now.

      • ChronicEd@kbin.social
        2·
        1 year ago

        Yeah! Considering being repeatedly attempted (and succeeding)…I’m guessing it may take a little while to deal with.

  • Sami@lemmy.zipEnglish
    5·
    1 year ago

    I’m not seeing anything different with lemmy.world on my end. Can anyone else confirm what OP is seeing?

    Edit: Reading that it was resolved in another thread.

    Second edit: Nope, not resolved

  • malloc@sh.itjust.worksEnglish
    4·
    1 year ago

    Single 🔧 vs Federated ActivityPub instance, who wins

    😂😂

    Side note: glad the lemmy devs and mods able to figure it out and all while doing this part time. Great community yall. Hope to contribute my time as well.