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

  • freeskier@centennialstate.social
    1·
    1 year ago

    Looks like my instance got hit with a bot. I had email verification enabled but had missed turning on captcha (captcha enable should be up with enabling email verification settings). 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.

    • sunaurus@lemm.eeOP
      1·
      1 year ago

      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)

      • voldern@lemmy.ml
        4·
        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;.

      • freeskier@centennialstate.social
        1·
        1 year ago

        What I ended up doing is getting the person_ids, from the local_user table, that had verified emails. Since my instance literally only has 4 real users I then just deleted all the rows in the person table that were local users and weren’t the 4 real users. It took almost 2 hours to run but it worked. User count automatically updated and corresponding rows in all the other tables were automatically deleted.

        This is the command for getting person_ids of verified users:

        SELECT person_id FROM local_user WHERE email_verified = 'true';

        Then to delete all the local users, except for those with verified emails:

        DELETE FROM person WHERE local = 'true' AND id NOT IN (<ID1>,<ID2>,<ID3>);

        Unfortunately, this isn’t really helpful for anyone with lots of real users. Unless a SQL wizard knows how to do this, making a python script that queries all the person_ids of unverified users then deletes those from the person table is probably easiest.

        I’ll copy this to the Matrix room too since it might help admins there.