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

  • 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.