A while back I stumbled upon an interesting issue with a hacked Asterisk server. It was routing calls to FreeConferenceCall.com and other free conference numbers.
https://www.mnxsolutions.com/security/i-accidentally-recorde...
https://www.mnxsolutions.com/security/i-accidentally-recorde...
These callers that were recorded, were not the ones trying to leverage the hacked server, but rather just dialed the number and were routed through it.