Blocking XMPP spam

After 6 years, I again got spam to my chat XMPP address again:

puddingcu@jabbim.sk 12:39
?OTRv23?
hi bro
?OTRv23?
puddingcu@jabbim.sk 12:40
?OTRv23?
puddingcu@jabbim.sk 12:42
?OTRv23?
example@cweiske.de 12:53
?OTRv23? disable OTR
- one day later -
puddingcu@jabbim.sk 10:48

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Prosody modules​

xmppbl​

It turns out there is something we can do this time: Use the XMPP real-time block list and configure our XMPP server to take part in that by sending spam reports to it.

First enable mod_anti_spam and tell it to talk with xmppbl.org.

The next step is to enable more modules for spam reporting: mod_spam_reporting (XEP-0377) and report_forward. Now the XMPP users - at least those with compatible clients like Conversations on Android - can report spam. The reports get sent to both the remote server's operator and the block list.

mod_anti_spam​

The mod_anti_spam documentation shows us the configuration to automatically block russian spammers sending those "?OTRv23?" messages:

anti_spam_block_patterns = {
  -- Block OTR handshake greetings (modern XMPP clients do not use OTR)
  "^%?OTRv2?3?%?";
}

Reporting spam with Conversations​

In the chat view with the spammer, click ⋮ and Contact details.

Now again ⋮ and Block contact. In the following popup, activate the checkbox Report this XMPP address for spamming..

Written by Christian Weiske.

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