this post was submitted on 20 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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Today, a bunch of new instances appeared in the top of the user count list. It appears that these instances are all being bombarded by bot sign-ups.

For now, it seems that the bots are especially targeting instances that have:

  • Open sign-ups
  • No captcha
  • No e-mail verification

I have put together a spreadsheet of some of the most suspicious cases here.

If this is affecting you, I would highly recommend considering one of the following options:

  1. Close sign-ups entirely
  2. Only allow sign-ups with applications
  3. Enable e-mail verification + captcha for sign-ups

Additionally, I would recommend pre-emptively banning as many bot accounts as possible, before they start posting spam!

Please comment below if you have any questions or anything useful to add.


Update: on lemm.ee, I have defederated the most suspicious spambot-infested instances.

To clarify: this means small instances with an unnaturally fast explosion in user counts over the past day and very little organic activity. I plan to federate again if any of these instances get cleaned up. I have heard that other instances are planning (or already doing) this as well.

It's not a decision I took lightly, but I think protecting users from spam is a very important task for admins. Full info here: https://lemm.ee/post/197715

If you're an admin of an instance that's defederated from lemm.ee but wish to DM me, you can find me on Matrix: @sunaurus:matrix.org

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[–] [email protected] 29 points 1 year ago (1 children)

This should be probably pinned.

[–] [email protected] 3 points 1 year ago
[–] [email protected] 14 points 1 year ago (1 children)

Here we go: https://overseer.dbzer0.com/

API doc: https://overseer.dbzer0.com/api/

curl -X 'GET' \
  'https://overseer.dbzer0.com/api/v1/instances' \
  -H 'accept: application/json'

Will spit out suspicious instances based on fediverse.observer . You can adjust the threshold to your own preference.

[–] [email protected] 6 points 1 year ago (1 children)

Nice! Would be cool if you could also include current statuses of captchas, emails, and application requirements.

[–] [email protected] 5 points 1 year ago (1 children)

Tell me how to fetch them and it will. ;)

[–] [email protected] 5 points 1 year ago (1 children)

I think the easiest option is to just iterate through the list of suspicious instances, and then check {instance_url}/api/v3/site for each of them. Relevant keys of the response json are site_view.local_site.captcha_enabled, site_view.local_site.registration_mode, and site_view.local_site.require_email_verification.

Since it's a bunch of separate requests, probably it makes sense to do these in parallel and probably also to cache the results at least for a while.

[–] [email protected] 4 points 1 year ago

It occurs to me that this kind of thing is better left to observer, as it's set up to poll instances and gather data. I would suggest you ask them to ingest and expose this data as well

[–] [email protected] 12 points 1 year ago (1 children)

CAPTCHA is the bare minimum. Who the hell turns it off?

[–] [email protected] 5 points 1 year ago (4 children)

There is an argument to be made that captchas can be automatically bypassed with some effort.

OTOH, the current wave of bots is quite clearly favoring instances with captcha disabled, so clearly it's acting as at least a small deterrent.

[–] [email protected] 6 points 1 year ago (1 children)

Sometimes, security just means not being the low-hanging fruit.

[–] [email protected] 5 points 1 year ago

Doing no captcha is like leaving the door open, hoping no-one breaks in, instead of at least closing the door (a closed door decreases chance of break in by near 100%, even if it's not locked)

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

captchas block script kiddies at the very least

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[–] [email protected] 10 points 1 year ago (1 children)

This might be related but I've noticed that someone is [likely automatically] following my posts and downvoting them. Kind of funny in a 'verse without karma.

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

Karma may mean nothing but the information space is a strategic domain.

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

I don't think it's the case here, as I've noticed this after posts in small communities:

  • c/linguistics (~240 members)
  • c/parana (1 member - new comm)

I think that the person/bot/whatever is following specific people.

[–] [email protected] 10 points 1 year ago (2 children)

99% of fedi instances should require sign-ups with applications and email. It does not make sense to let in users indiscriminately unless you have a 24h staff in charge of moderation.

[–] [email protected] 24 points 1 year ago (2 children)

We're trying to capture the reddit refugees as well. It's a fine-line to walk.

[–] [email protected] 11 points 1 year ago (1 children)

Agreed. An application that must be human reviewed is a very large gate that many people will see and just close the site. Myself included.

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[–] [email protected] 10 points 1 year ago (1 children)

Email + Captcha should be doable right?

[–] [email protected] 11 points 1 year ago

yes, that's the bare minimum until we get better toolset

[–] [email protected] 8 points 1 year ago

Email verification + captcha should be enough. The application part is cringe and a bad idea, unless you really want to be your own small high school clique and don't have any growth ambitions, which is perfectly fine but again should not be expected from general instances looking to welcome Redditors.

[–] [email protected] 9 points 1 year ago (1 children)

Thanks for the heads up, StarTrek.website has enabled CAPTCHA and purged the bots from our database.

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

Starfleet takes changeling infiltrations seriously :P

[–] [email protected] 8 points 1 year ago (2 children)

Sounds like a spez sponsored attack on Lemmy.

[–] [email protected] 7 points 1 year ago

Or just the unavoidable spam bot accounts coming as long as it's easy and the instance operators being still unprepared.

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

I highly doubt spez did this. Reddit is currently doing fine. Even if it all goes away he's sitting on over a decade of genuine human conversations he can sell to AI companies and make millions. He isn't worried.

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

Steve Huffman doesn't do anything, he's a greedy little pigboy who profits off of the creation of his dead "friend". He claims ownership of your ideas, for reddit's exclusive profit, at no benefit (if anything, at penalty) to yourself.

However it would be naive to assume that he hasn't directed at least some shade towards reddit. Almost as naive as to think that Google doesn't create bots to target websites that don't use their own captcha services.

PSA: When "proving you're human", always try to poison the data. They're using your input to train visual AI, without paying you for your efforts. With Google, they will typically put the training up front - there will be one or two images that a bot isn't sure about. If you give the unexpected response, the next test will be one that the machine knows, to check that you're a human who knows what they're talking about. With hcaptcha or some others, they might put the obvious one first, then check your guesses are human after.

The services will determine that you're human by other means anyway (eg mouse movements) and eventually let you through, but by giving them the wrong answer when they don't know but the right answer when they do, you can make their AI less effective.

They should be paying you for your input into their commercial enterprise, so fuck them.

[–] [email protected] 6 points 1 year ago (1 children)

It was brought to my attention that my instance was hit with the spam bots regs. I've disabled registration and deleted the accounts from the DB. is there anything else I can do to clear the user stats on the sidebar?

[–] [email protected] 4 points 1 year ago

You can do this by updating site_aggregates.users in your database (WHERE site_id = 1)

[–] [email protected] 5 points 1 year ago (1 children)

I'm noobish, but could they be defederated until they get their act together before they spam everybody?

[–] [email protected] 7 points 1 year ago

Yes, and I believe some instances are already doing this

[–] [email protected] 5 points 1 year ago (1 children)

I'm sure it's different per instance, but is there any discussion on what is being done with the collected emails?

I understand the need to fight bots and spam, but there are also those of us who don't want to associate emails with accounts so some privacy-related way of handling this would be appreciated.

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

there's plenty of services that provide one-use emails or disposable ones

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

True, I use one myself.

That's a cool instance you're running over there, by the way! I appreciate it.

[–] [email protected] 4 points 1 year ago* (last edited 1 year ago) (3 children)

Any tips on how to get rid of all the spam accounts? I have been affected by this as well and thankfully captcha stopped them, but about 100 bots signed up before I could stop.

Normally i'd just look through all the accounts and pick out the 4 or so users that are real. But there is no apparent way to view every user account as an admin.

Edit: There is a relevant issue open on the lemmy-ui repo, for those interested: https://github.com/LemmyNet/lemmy-ui/issues/456

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

Did you figure out how to clean it up? You can see a list of users in your local_user table.

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[–] [email protected] 4 points 1 year ago
[–] [email protected] 3 points 1 year ago
[–] [email protected] 3 points 1 year ago

I know from talking to admins when pbpBB was really popular that fighting spammers and unsavory bots was the big workload in running a forum. I'd expect the same for Fediverse instances. I hope a system can be worked out to make it manageable.

As a user I don't have a big problem with mechanisms like applications for the sake of spam control. It's hugely more convenient when an account can be created instantaneously, but I understand the need.

I do wonder how the fediverse is going to deal with self-hosting bad actors. I would think some kind of vetting process for federation would need to exist. I suppose you could rely on each admin to deal with that locally, but that does not sound like an efficient or particularly effective solution.

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

Looks like my instance got hit with a bot. I had email verification enabled but had missed turning on captcha. The bot used fake emails so none of the accounts are verified, but still goes towards account numbers. Is there really any good way to clean this up? Need a way to purge unverified accounts or something.

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

How comfortable are you with SQL? You can see all unused verifications in the email_verification table. You should be able to just delete those users from local_user, and then update your user count with the new count of the local_user table in site_aggregates.user (where site_id = 1)

[–] [email protected] 4 points 1 year ago

Thank you for proactively contacting me regarding this @[email protected]. I've had this issue on my https://feddi.no instance, but I have added a captcha and registration applications now. Hopefully it will alleviate some of the problem.

All of the bots accounts seems to have a number in their email so I manually looked through the list of users in email_verification that contained numbers in the email to look for false positives:

select * from email_verification where email ~ '[0-9]+';

before running

delete from local_user where id in (select local_user_id from email_verification);

to delete the users.

By suggestion from @[email protected] I updated site_aggregates to reflect the new users count on the instance:

UPDATE site_aggregates SET users = (SELECT count(*) FROM local_user) WHERE site_id = 1;.

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

Today, a bunch of new instances appeared in the top of the user count list. It appears that these instances are all being bombarded by bot sign-ups.

Yup, I noticed this as well.

Hopefully the mods of the instances will notice this and remove these accounts quickly! Despite this, I think the mods of all instances, and of all communities, had better brace themselves for incoming spam and hate speech.

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

Maybe this is what's implied or I'm just being silly; What is to stop a bad actor spinning up a Lemmy instance, creating a bunch of bot accounts with no restrictions, and spamming other instances? Would the only route of action be for the non spam instances to individually defederate the spam ones? Seems like that would be a bit of a cat and mouse situation. I'm not too familiar with the inner workings and tools that Lemmy has that would be useful in this situation

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

They can do this, and it is cat and mouse. But...

  1. It generally costs money to stand up an instance. It often requires a credit-card, which reduces anonymity. This will dissuade many folks.
  2. A malicious instance can be defederated, so it might not be all that useful.
  3. People can contact the security team at the host providing infra/internet to the spammer. Reputable hosts will kill the account of a spammer, which again is harder to duplicate if the host requires payment and identity info.
  4. Malicious hosts that fail to address repeated abuse reports can be ip-blocked.
  5. Eventually Lemmy features can be built to protect against this kind of thing by delaying federation, requiring admin approval, or shadow -banning them during a trial period.

Email has shown us that there's a playbook that kind of works here, but it's not easy or pleasant.

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

One thing I like about lemmy was having to put in an application and waiting for approval. I knew I was vetted and others here were too.

Figure that alone could keep out most of the trolls and definitely the bots.

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