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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.

  • TheDude
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    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.

    • darkstar
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      1 year ago

      Thanks for the update, we all appreciate it!

    • SimplePhysicsOP
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      1 year ago

      Nice! Yeah, seems to be that lemmy.world logo emoji that stole your cookies. There were people compromised accounts posting them everywhere on .world.

    • merc
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      1 year ago

      Who would have thought an emoji could be a source of a vulnerability.