Possible to exploit system by dialing into voicemail?

Hi we have AsteriskNow Ver. 11.2.1 running with FreePBX on an internal server, which is not accessible from the outside.

We’ve discovered extremely long duration calls coming into the system. Since it is an 800 number being redirected we are charged a good amount for this.

Anyone have any idea what they are trying to do? How to stop them?

Thanks for the quick reply… GEEZ, the things only been up for a month.

Anyone know if there is some way to limit the call in asterisk, or when I call the Telco is this something they will take care of? The bill is showing over $400 in charges already for this crap!

Settings>Voicemail Admin>[Settings]
maxsecs - Set this to a comfortable length. 60, 90, 120 this is the maximum message time
maxsilence - If the call is dead air this can kill it too. set this to like 10 seconds. If the other end doesn’t speak in 10 seconds it ends the recording.

Note this could have been a legit call where you did not receive a CPC Disconnect. Have you run that number against your customers? Have you listened to the recorded message? Have you called it?

I’m made those setting changes which seems logical, thanks very much for that.

Yea these are definitely fraudulent, you can see the number continuously call our system seconds apart in very large blocks. Hopefully the settings you pointed out will do the trick.

Thanks again everyone! The telco of course was no help.

If they are not changing numbers you may consider the admin>blacklist. You may also wish to see if your provider can block the number on their side.