this post was submitted on 10 Jul 2023
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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
onloadproperty 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.
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.
As for the version, my instance reports it as
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.
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.
Thanks for digging in and sharing your findings!