this post was submitted on 18 Jun 2023
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Lemmy

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Everything about Lemmy; bugs, gripes, praises, and advocacy.

For discussion about the lemmy.ml instance, go to [email protected].

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cross-posted from: https://lemmy.cat/post/6385

It is currently possible, through Lemmy's API, to create accounts automatically and without limit if verification by email address or captcha is not activated. I'd advise you to activate one or both of them NOW!

After registering x number of accounts (currently I could do thousands), all you have to do is list all the existing communities for each of the account to publishes one new post per community, or more. I'll leave you to picture the mess.

(I apologise to the administrators of sh.itjust.works, I should have done the test with my own server.)

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[–] [email protected] 3 points 1 year ago (1 children)

I was playing a bit with the API today and yea it might even be a bit too easy at the moment. You can easily use that army of Lemmy bots to upvote all your posts.

We should probably make it very clear in tutorials and setup guides that no email verification and no captcha is very insecure.

[–] [email protected] 1 points 1 year ago

Stupid of me, I hadn't thought about upvotes, but it's clear that this is perhaps the most "quiet" and dangerous type of abuse.

[–] [email protected] 2 points 1 year ago (1 children)

This is indeed not an ideal situation, but I guess on most instances this isn't possible. I agree instances should require a captcha of some sort for signing up.

[–] [email protected] 3 points 1 year ago

Unfortunately lemmy devs removed captchas recently https://github.com/LemmyNet/lemmy/issues/2922 so email verification and/or rate limiting is probably the only real option for protection.

[–] [email protected] 2 points 1 year ago

I saw some small instance owners saying they were going to enable open registration and I couldn't help thinking how bad an idea that sounded all around... For exactly a situation such as this inevitably emerging.

[–] [email protected] 1 points 1 year ago

+1 to that. Also the email domain matters. It's relatively easy to set up hundreds of disposable emails on random domains vs ones like Gmail.

Phone number is another solid anti abuse signal. SIM cards are harder to come by in large quantities.

[–] [email protected] 0 points 1 year ago (1 children)

Not sure how email verification should help. Just add a couple of line to role a email address and then open the verification link.

[–] [email protected] 1 points 1 year ago

If you don't have your own domain, it's hard to generate mass email addresses, at least with large providers.

So if someone uses his custom domain to mass-generate emails, it's easier to delete all accounts that use this same email provider.

[–] [email protected] -1 points 1 year ago

Fuck captcha