Mykola Konrad
Mykola Konrad is the Director of Enterprise Product Management at Sonus Networks. At Sonus, Mykola is leading the introduction of...
Read Full Bio >>

Mykola Konrad | June 09, 2011 |


Is That Call Normal? Is it Even a Human Being?

Is That Call Normal? Is it Even a Human Being? There are two general ways to detect fraudulent calls: CDR pattern matching and media-stream analysis.

There are two general ways to detect fraudulent calls: CDR pattern matching and media-stream analysis.

I'm on the train from New York to Boston following two days of meetings with customers whose contact centers have recently been attacked by SIP-generated denial-of-service attacks. We discussed ways to protect their networks against future attacks of this kind. We decided that the first layer of protection should be a session border controller that can protect against packet attacks and can perform enough deep-packet inspection to look for malformed SIP headers. For these particular customers, however, that was not enough. As I explained in my previous post (If it Could Happen to Them...), the inbound calls are “normal” SIP calls.

So how can you detect these fraudulent calls? Well, there are two general ways to do this: CDR pattern matching and media-stream analysis.

CDR pattern matching consists of analyzing the historical call-pattern variables (duration, time of day, caller ID, called number, etc.) to determine a profile that is "baseline normal." As calls come in that do not match the profile based on any of these variables, they can be flagged and appropriate action taken (more on that in a bit).

Media-stream analysis looks at the actual media coming into your voice network; for SIP calls it looks at the RTP stream. It analyzes the RTP stream to make sure it contains a human voice as opposed to a music file or other type of computer-generated media. Again, once a call is flagged as "not human," action can be taken on it. The key thing here is to be able to set threshold values for what "non-human" means. You want to make sure that all the calls you identify are truly non-human.

This brings me to the third capability that must be present--the ability to take action once an intrusion is identified. The action can terminate the call or perhaps reroute the call to specially trained agents. So there has to be some sort of integration with your dial-plan manager. You put all of these capabilities together and you have a voice intrusion prevention system--a device that builds on the "firewall" functionality of a typical SBC to extend protection to the voice application layer.

So the enterprises I mentioned earlier are exploring products that combine this functionality in order to enhance their voice security. As we all know, sometimes it takes an actual security incident to acknowledge that it can happen to anyone--including you. But there are products on the market today that can help prevent these types of attacks.


April 19, 2017

Now more than ever, enterprise contact centers have a unique opportunity to lead the way towards complete, digital transformation. Moving your contact center to the cloud is a starting point, quick

April 5, 2017

Its no secret that the cloud offers significant benefits to enterprises - including cost reduction, scalability, higher efficiency, and more flexibility. If your phone system and contact center are

March 22, 2017

As today's competitive business environments push workforces into overdrive, many enterprises are seeking ways of streamlining workflows while optimizing productivity, business agility, and speed.

April 28, 2017
Change isn't easy, but it is necessary. Tune in for advice and perspective from Zeus Kerravala, co-author of a "Digital Transformation for Dummies" special edition.
April 20, 2017
Robin Gareiss, president of Nemertes Research, shares insight gleaned from the firm's 12th annual UCC Total Cost of Operations study.
March 23, 2017
Tim Banting, of Current Analysis, gives us a peek into what the next three years will bring in advance of his Enterprise Connect session exploring the question: Will there be a new model for enterpris....
March 15, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, discusses the evolving role of the all-important session border controller.
March 9, 2017
Organizer Alan Quayle gives us the lowdown on programmable communications and all you need to know about participating in this pre-Enterprise Connect hackathon.
March 3, 2017
From protecting against new vulnerabilities to keeping security assessments up to date, security consultant Mark Collier shares tips on how best to protect your UC systems.
February 24, 2017
UC analyst Blair Pleasant sorts through the myriad cloud architectural models underlying UCaaS and CCaaS offerings, and explains why knowing the differences matter.
February 17, 2017
From the most basics of basics to the hidden gotchas, UC consultant Melissa Swartz helps demystify the complex world of SIP trunking.
February 7, 2017
UC&C consultant Kevin Kieller, a partner at enableUC, shares pointers for making the right architectural choices for your Skype for Business deployment.
February 1, 2017
Elka Popova, a Frost & Sullivan program director, shares a status report on the UCaaS market today and offers her perspective on what large enterprises need before committing to UC in the cloud.
January 26, 2017
Andrew Davis, co-founder of Wainhouse Research and chair of the Video track at Enterprise Connect 2017, sorts through the myriad cloud video service options and shares how to tell if your choice is en....
January 23, 2017
Sheila McGee-Smith, Contact Center/Customer Experience track chair for Enterprise Connect 2017, tells us what we need to know about the role cloud software is playing in contact centers today.