O'Reilly logo

VoIP Hacks by Theodore Wallingford

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Hack #87. Intercept and Record a VoIP Call

This is the ultimate sneaky way to intercept and record VoIP calls.

I'm going to demonstrate why people say VoIP isn't secure. If you've got a laptop and a patch cable, you can record calls from a Cisco CallManager IP telephony network or even from a Vonage subscriber. More specifically, you'll be doing so without the need for port spanning on the switch [Hack #86] and without installing a recorder or sniffer on the device you're trying to record [Hack #85] .

Instead, you'll be resorting to a tactic that's, well, unnatural. In fact, if you do this outside the test lab, it could be considered unethical, too, so be careful. I am about to teach you how to secretly listen in on other users' VoIP calls without having any direct contact with their VoIP phones or PCs and without being the administrator of the local network. Be advised, though, I'm not recommending that you ever do this in the field. I'm just passing on some knowledge I picked up while working as a networking consultant.

Get to Know Cain & Abel

While you're here, make sure you've read "Log and Record VoIP Streams" [Hack #86] , which introduces the software tool I'll be using to make all this happen: Cain & Abel. If you don't know Cain & Abel, go back a hack, read it through, and you'll be able to proceed with confidence.

Now, on to the hack.

An Ethernet switch has anywhere from 4 to 48 ports where Ethernet devices like PCs and IP phones can connect. Each device connected to the ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required