Did you know that Apple — a $3.5 trillion company today — owes its existence to an illegal, underground device? Back in the early 1970s, before the first Apple computer was even a concept, Apple co-founders Steve Jobs and Steve Wozniak crafted a device called a "blue box." This small but powerful tool allowed users to make free long-distance phone calls by "hacking" phone systems, a huge deal in an era where long-distance rates could exceed $3 per minute.
What Was the Blue Box?
The blue box exploited a vulnerability in the telephone system, specifically through a process known as “phone phreaking.” Phreaking allowed users to manipulate phone networks by playing specific sounds into a phone’s handset. In this case, a tone of 2600 Hertz, which was originally used by phone companies as a control signal, could “fool” the system into believing a line was free, typically when a call was ended.
The idea of manipulating phone systems with sound was discovered in the late 1950s by Joe Engressia, a blind child with perfect pitch who could whistle the exact 2600 Hz tone. This breakthrough opened doors for a community of "phone phreaks," people who learned to exploit the phone system for free calls.
How the Blue Box Worked
To make a free call, a user would first dial a toll-free number to avoid any initial charges. When the phone began ringing on the other end, the blue box would play the 2600 Hz tone, tricking the system into thinking the call had been disconnected. The line was marked as “free,” but the caller remained connected. They could then use the blue box to dial their intended number, bypassing long-distance fees entirely.
Despite its effectiveness, only about 100 blue boxes were ever produced, each sold for around $170. Due to their rarity, one of these devices was auctioned in 2017 for an astounding $125,000, close to the price of the latest iPhone at the time.
The Rise of Phone Phreaking
The popularity of phone phreaking didn’t go unnoticed. The community grew as underground magazines published articles detailing how to create similar devices. In response, phone companies developed countermeasures to combat the illegal usage. One significant development was Signaling System 7 (SS7), which separated control signals from user lines, making the system more secure against phreaking attempts.
Despite these countermeasures, phreakers continued finding ways around them. One method in the 1980s involved brute-forcing codes for calling cards, allowing users to bypass long-distance fees. By the mid-1980s, the tactic became widespread, with college students heavily involved. Phone companies were losing up to half a billion dollars annually from these hacks until direct dialing for long-distance calls became universal, eventually closing the loophole.
Modern Phone Phreaking
Though SS7 was effective at the time, its vulnerabilities persist in some cases today. A recent demonstration showed how attackers could still intercept calls by accessing SS7 networks. By buying SS7 access, hackers can spoof a user’s location, rerouting calls and texts to their own devices. This exploit highlights the ongoing issues with telecommunications security even in modern networks.
For a fascinating demonstration of how SS7 vulnerabilities continue to pose security risks, check out the collaboration between Linus Tech Tips and Veritasium. They illustrate how attackers can reroute calls and texts by exploiting these legacy systems.
The blue box and the early days of phone phreaking serve as a reminder of how early tech pioneers like Steve Jobs and Steve Wozniak came from a world of bold, often risky, innovation. From these unconventional origins, Apple emerged, forever changing the tech landscape.
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