You can purchase "Seven Deadliest Unified Communications Attacks" from many different sources, including:
- O'Reilly as an ebook
- Amazon.com in both print and ebook
- Elsevier (publisher) in both print and ebook
If you wish to purchase an ebook, I do encourage you to consider O'Reilly. Buying direct from O'Reilly offers multiple excellent benefits, including:
- DRM-free - no stupidity with license restrictions.
- Free lifetime access
- Multiple formats (ex. ePUB, PDF, Kindle, etc.)
- Free updates
- Sync with Dropbox and other similar services
Having said that, I just appreciate that you are considering purchasing this book from whichever vendor you choose!
Thank you for your purchase and I hope that you find the book helpful in making your UC and VoIP systems more secure. Please don't hesitate to contact me if you have questions about the book!