Tariff "Free". Hacking a payphone at PHDays

Since Positive Hack Days is a forum dedicated to practical issues of information security, there were highly practical competitions in the competition program (for example, a competition on hacking hashes and searching for information hidden on the Internet ).



One of the competitions, where you could work not only with your head, but also with your hands, was the “ 2600 ” competition, during which participants had to demonstrate their phreaking skills and hack a payphone. Any visitor to the Positive Hack Days forum could take part. Contestants had to make a call from a payphone to a predetermined number and at the same time return the token to the organizers.





It was possible to prepare for the competition by reading this excellent post .

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An old payphone was purchased for the competition, originally from the 90s. He was not quite working: it was possible to call him without coins. To fix this, we screwed a coin acceptor to the device, for which modern coins worth two rubles were good.



To test the payphone after surgery, I had to connect it to the office PBX: everything worked with a bang. In order for the payphone to function, a simple PBX was acquired during the forum, to which the device was connected to the Digital October techno center.



During the competition, participants received special PHDays tokens with a small hole. The PHDays token weight was equal to the weight of a two ruble coin.







To clarify the rules of the competition and the technical subtleties of phreaking in Russian, a beautiful girl model was sitting on the platform of the forum next to the payphone. Her help came in handy when foreign forum participants with surprise studied a strange piece of iron and tried to understand why the blue-box wasn’t working during pulse dialing. It is clear that a crowd constantly gathered around the telephone, consisting not only of the participants of the competition, but also of those who wanted to talk to the beauty :)







The winners received commemorative prizes and gifts: everything is as it should :) The competition aroused considerable interest and was even covered on CNewsTV:







The “2600” contest will definitely be presented at Positive Hack Days next year!