The Public Switched Telephone Network has always been an enigma to many. In the past, only a select few were chosen and imparted with the knowledge and secret information about the inner workings, which remained protected with Masonic-like “security through obscurity“. The secrets of ‘The Phone Network’ were passed between generations on a “need-to-know” basis. From the configuration of the network itself to the details of its Central Office switching architecture, the facts were rarely made available to the public. The result was that only a relatively small group of people existed that well understood the core operations.

In contrast, the communications networks of today were built through collaboration and open standards-based principals. The boundless social outreach machine called the Internet that enabled that contributory environment. has also allowed the hacker community to flourish. Along with their implacable dumpster diving tactics, and infiltration into our work-stream, it has become Lord of the Flies, but this time with ones and zeros.

It was only a matter of time before the well-hidden secrets behind the telephone network that kept the vulnerabilities of our critical 911 infrastructure from being compromised. leaked out and created havoc. Our very own creation is what has allowed the hackers, and the ‘phone-phreakers’ to spread their knowledge at light speed, letting the proverbial ‘genie’ out of its bottle along with detailed information on how to hack the 911 networks. This information is being used to target Public Safety (commonly known as SWATting) and is quickly going mainstream.

At the 2014 DEF CON conference, the oldest and largest hacker convention in existence, Christian Dameff, MD (@CDameffMD) along with Jeff Tully, MD (@jefftullymd) openly analyzed the archaic architecture of the 911 network, and the failure of that network to evolve with technology.

What was once a well-working secure data repository, was now a leaking sieve of information, easily attacked, spoofed, and put under the control of nefarious resources to do their bidding.

One question prevailed, “Just how did these two medical doctors figure out how to hack this complex machinery and discover this security problem?

The answer was all too simple. These two doctors were actually “researchers with a passion for the intersection between security and healthcare” which is why they were attendees at a security conference. Over their years of research, they noticed that while analyzing 911 recordings released to the public, the recordings often included strings of Multi-Frequency tones. This is because the legacy 911 network is an analog network that passes information through these audio tones. The conclusion by the doctors was that this could easily expose the network for a man-in-the-middle attack.

As it turns out, hacking the legacy telephone network is certainly nothing new. Whether it was the “blue box” built by Steve Wozniak or the Cap’nCrunch whistle used by John Draper that was easily modified to emit a perfect 2600 Hz tone (effectively putting the nation’s long-distance network at your beck and call before digital switching technology was made available), hacking has been an active pastime of many of the great innovators today.

Its original usage was not nefarious, just an attempt to bypass the incredibly high toll charges that they were subject to by the telephone company for long-distance and international calls. The practice went mainstream after a story was published in the October 1971 issue of Esquire Magazine. A copy of that article is still available online here.

While long-distance phreaking has all but died out, since toll fraud is no longer popular thanks to flat-rate cellular plans and unlimited home phone long distance available for unbelievably low rates, phone “phreaking” took on a more sinister nature. I’ll dive into the SWATting phenomenon in another Blog.

I welcome your comments, suggestions, or queries.

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© 2020, All Rights Reserved, Mark J. Fletcher, ENP
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