https://www.cs.umb.edu/~emm/crackdown/ http://www.mit.edu/hacker/hacker.html https://en.wikipedia.org/wiki/The_Hacker_Crackdown The Hacker Crackdown Law and Disorder on the Electronic Frontier by Bruce Sterling Part 1: Crashing The System " In the meantime, however, police and corporate security maintained their own suspicions about "the chances of recurrence" and the real reason why a "problem of this magnitude" had appeared, seemingly out of nowhere. Police and security knew for a fact that hackers of unprecedented sophistication were illegally entering, and reprogramming, certain digital switching stations. Rumors of hidden "viruses" and secret "logic bombs" in the switches ran rampant in the underground, with much chortling over AT&T's predicament, and idle speculation over what unsung hacker genius was responsible for it. Some hackers, including police informants, were trying hard to finger one another as the true culprits of the Crash. Telco people found little comfort in objectivity when they contemplated these possibilities. It was just too close to the bone for them; it was embarrassing; it hurt so much, it was hard even to talk about. There has always been thieving and misbehavior in the phone system. There has always been trouble with the rival independents, and in the local loops. But to have such trouble in the core of the system, the long-distance switching stations, is a horrifying affair. To telco people, this is all the difference between finding roaches in your kitchen and big horrid sewer-rats in your bedroom. ... As more and more switches did have that bit of bad luck and collapsed, the call-traffic became more and more densely packed in the remaining switches, which were groaning to keep up with the load. And of course, as the calls became more densely packed, the switches were much more likely to be hit twice within a hundredth of a second. It only took four seconds for a switch to get well. There was no physical damage of any kind to the switches, after all. Physically, they were working perfectly. This situation was "only" a software problem. But the 4ESS switches were leaping up and down every four to six seconds, in a virulent spreading wave all over America, in utter, manic, mechanical stupidity. They kept knocking one another down with their contagious "OK" messages. It took about ten minutes for the chain reaction to cripple the network. Even then, switches would periodically luck-out and manage to resume their normal work. Many calls -- millions of them -- were managing to get through. But millions weren't. ... On Tuesday, September 17, 1991, came the most spectacular outage yet. This case had nothing to do with software failures -- at least, not directly. Instead, a group of AT&T's switching stations in New York City had simply run out of electrical power and shut down cold. Their back-up batteries had failed. Automatic warning systems were supposed to warn of the loss of battery power, but those automatic systems had failed as well. This time, Kennedy, La Guardia, and Newark airports all had their voice and data communications cut. This horrifying event was particularly ironic, as attacks on airport computers by hackers had long been a standard nightmare scenario, much trumpeted by computer- security experts who feared the computer underground. There had even been a Hollywood thriller about sinister hackers ruining airport computers -- Die Hard II. Now AT&T itself had crippled airports with computer malfunctions -- not just one airport, but three at once, some of the busiest in the world. By 1991 the System's defenders had met their nebulous Enemy, and the Enemy was -- the System. " https://www.nytimes.com/1990/01/16/us/experts-diagnose-telephone-crash.html https://users.csc.calpoly.edu/~jdalbey/SWE/Papers/att_collapse.html http://www.phworld.org/history/attcrash.htm The Risks Digest - Volume 9, Issue 62 - February 26, 1990. Cause of AT&T network failure "Peter G. Neumann" Fri, 26 Jan 90 14:24:30 PST
From Telephony, Jan 22, 1990 p11: The Crash of the AT&T Network in 1990 ...
https://en.wikipedia.org/wiki/Signalling_System_No._7 https://stackoverflow.com/questions/5928168/stupid-mistakes-in-c-break-switc... If you paid serious attention to every rumor out and about these hacker kids, you would hear all kinds of wacko saucer-nut nonsense: that the National Security Agency monitored all American phone calls, that the CIA and DEA tracked traffic on bulletin-boards with word-analysis programs … — Chapter 2, The Digital Underground Cypherpunks... such nonsense they are.