Flag traffic from Tor exit nodes

Elastic Stack Logstash
1

I'm looking to flag any traffic hitting our edge that appears to come from a tor exit node.

I've pulled a list of all exit nodes, which I'll later cron updates to, with:

curl -s https://check.torproject.org/exit-addresses | awk '/ExitAddress/ {print $2": Torified"}'

Then I'm planning to add a translate filter to check the exit list, and mutate that into a tag:

translate {
  field => "client_ip"
  destination => "tor_status"
  dictionary_path => "/etc/logstash/torexits.dict"
}
if [tor_status] {
  mutate {
    add_tag => "torified"
    remove_field => "tor_status"
  }
}

This works, but it seems a bit messy. On the other hand I'm not sure I want an array with 1000+ IPs sitting in my logstash config. It would make scheduled updates to the list trickier, too, requiring both templating and a restart.

Is there a way to check whether a field's contents exist in a list and, if so, add a tag... without adding unnecessary logic and without writing the list into config?

2

You could add in an exec input to do the curl into the translate file every so often too.

But until dynamic reloading gets released (5.0 I think?), this is the best way.

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