HE:V is a real eye-opener for those of us who don’t perform VoIP pen testing or assessments. It’s important to remember that the original HE books were written by Foundstone consultants who put their work experience in book form. HE books that continue this tradition tend to be successful, and HE:V is no exception. Good HE books also introduce a wide variety of tools and techniques to exploit weaknesses in targets, and HE:V also delivers in this respect. HE:V also extends attacks beyond what most people recognize. For example, everyone probably knows about low-level exploitation of VoIP traffic for call interception and manipulation. However, chapter 6 discusses application-level interception.

HE:V goes the extra mile by introducing tools written by the authors specifically to implement attacks. In at least one case the authors also provide a packet capture (for the Skinny protocol) which I particularly appreciate. HE:V also looks ahead to attacks that are appearing but not yet prevalent, like telephony spam and voice phishing. Taken together, all of these features result in a great book. You should already be familiar with the common enumeration and exploitation methods found in HE 5th Ed, because the HE:V authors wisely avoid repeating material in other books (thank you).

If you want to understand VoIP, how to attack it, and how to defend it, I highly recommend reading HE:V. The book is clear, thorough, and written by experts.
Rating: 5 / 5

Chapter 1 talks about Google hacking, or in other words, using the Internet to find out things about a target network. They show that Google can be a crucial tool in finding out what type of hardware and software you use in your VoIP networks, and in some cases will give vital clues even about how to login to the management systems of your network from the Internet. If this doesn’t scare the bejesus out of you, then proceed on to further chapters about more VoIP-specific issues.

Chapters 2 and 3 detail the kind of tools a hacker might use to scan your network and enumerate all the devices, i.e. build their own map of how your network is laid out, right down to the telephone numbers and MAC addresses of desktop phones. Chapter 4 talks about Denial-of-Service, and the kind of attack resources that hackers might use to cripple a telephony network.

Chapter 5 is on VoIP eavesdropping, talking about some existing tools that can be used for this (Oreka, Wireshark and the unpleasantly named vomit), and as in the earlier chapters, some suggestions on how to defend against such a type of threat. Chapter 6 goes further to explain how a VoIP man-in-the-middle attack might be mounted, giving the possibility not just to listen, but to modify, replace or remix the audio stream.

Chapters 7, 8, 9 talk about specific platform threats, namely to Cisco Unified CallManager, Avaya Communication Manager and the Asterisk PBX. The vendors have added their own comment to these chapters, at the request of the authors. Chapter 10 takes in Softphones, including Google Talk, Gizmo, Yahoo and of course the ever popular Skype.

Chapter 11 describes VoIP fuzzing, or in other words, testing protocol stacks for flaws, so this is useful for those developing VoIP systems and applications. Chapter 12 talks about disruption of networks using flooding techniques and chapter 13 talks about Signaling and Media Manipulation.

The final section of the book is entitled Social Threats, and talks about SPAM over Internet Telephony (SPIT) in Chapter 14, followed by Voice Phishing in Chapter 15. Neither of these threats are in frequent use yet, but their use is certain to increase in the future, so this is a good moment to get to grips with what this means.

This is a highly technical book, but for managers responsible for IT security but not immersed in the details I would say this: buy the book, and read the case studies. There are five sections to the book, and each starts with a short case study. Invest 20 minutes in reading these, and you will start to get an appreciation for how important VoIP Security will be in the future. Then pass the book on to your hands-on security guy and tell him to read it from cover to cover.

Rating: 5 / 5

It’s definitely focused on SIP and RTP, and focused on Enterprise VoIP deployments. The authors appear to be unaware of hosted / carrier VoIP, such as used by Verizon. The authors don’t mention anything about BroadSoft BroadWorks, MetaSwitch, Acme Packet, Sylantro, or others, though their general technology coverage certainly relates to these systems. I also wish they had considered some of the very popular SIP phones — e.g., Linksys and Polycom.

They give examples of using numerous VoIP security-scanning / exploit tools. The theoretical attacker in the book likely has physical access to the target network, or at least layer-2 (Ethernet) access. Many of the attacks are much more difficult or impossible if you’re attacking across the Internet.

Still, coverage of the tools is very useful to a Carrier VoIP researcher.
Rating: 3 / 5