Can the internet crash? How the unthinkable could happen

If the dark day comes when the internet does experience a global crash, the thing that takes it down will be, almost by definition, the thing we didn't see coming.

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A thought experiment

Maybe your spreadsheet won't load. Or Netflix gets laggy and your Wi-Fi connection stalls out. And the thought occurs, ‘What if the whole internet crashed?’

And once you wonder it, the thought won’t go away. What is the internet anyway? A bunch of interconnected computers. Couldn’t they crash, all at once? What would it take? For those of us who deal with technology for a living, the question bears consideration.

Think laterally for a minute and the spooky questions pile up: What would it do to the markets, the military, the hospitals? How would we access those back episodes of Arrested Development?

Follow along as we take a brief and speculative pass at this complex issue and attempt to answer this doomsday inquiry: Could the internet crash? Conventional wisdom tells us no: As a planetary network of computers and machines, the internet is too big, too decentralized, and too redundant to fail all at once. And yet doomsday scenarios have been proposed, and not just by the tinfoil-hat crowd.

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A network of networks

Let’s start with that conventional wisdom: It's generally accepted that the internet, as a network, cannot crash because it's not a single network at all. It is a massive, interconnected network of networks. It is the most powerful and intricate communication matrix ever assembled by humankind. The internet changes from minute to minute – second to second, even – as different computers and other machines log in and drop out.

Paul Levinson, author and professor of communication and media studies at Fordham University, has spent much of his career analyzing the internet through the lens of systems theory. He says the very nature of the internet, as a radically decentralized tangle of individual networks, largely protects it from crashing.

“It would be very, very hard for the entire internet to crash based on an important systems theory principle called redundancy,” Levinson says. “There are so many backup systems, so many workarounds, so many different ways to get from point A to point B. All these come online instantly and automatically if the system fails.”

But this is only slide 2, so clearly the story doesn't end here.

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Nodes and wires

For the internet to experience a total global collapse – or even a regional collapse based in, say, North America – some kind of agency or event would have to simultaneously disable all the network service providers (NSPs) that were online at that time. NSPs link commercial ISPs to the internet backbone and they're scattered all over the globe, each with multiple facilities distributed across the geographical area that the service covers.

These NSPs provide the very infrastructure of the internet. If one fails, internet traffic is simply routed around that problem by way of the thousands of other available paths. In terms of its physical components, each of these paths is made up of various hardware elements: The actual servers, cables and equipment. But there is no way to crash the internet by disabling one piece of hardware – or even one thousand pieces. There's no central cord to cut, no main plug to pull. To stop or even significantly slow the internet across any sizable geographic area, you'd have to do a lot of damage in a lot of different places.

“It would require a catastrophe,” Levinson says. “An event or series of events of such massive physical destruction that large portions of the internet's underlying hardware – the cables, the servers, the facilities – were severely damaged.”

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Catastrophe!

The good news, if that's the right term, is that any global catastrophe big enough to take out all the world's NSPs would likely kill all life on the planet as well. These would be extinction-level events like an asteroid impact or global thermonuclear war, Levinson says. If we do face such an eventuality, internet access will be low on our list of immediate concerns.

However, smaller disasters could certainly knock out portions of the internet temporarily. In fact, they already have. The most vulnerable component of the internet backbone is the network of undersea fiber optic cables that connect the continents. These cables – more than 400 worldwide at last count – are regularly cut and ruptured by rock slides, undersea earthquakes, and other natural phenomena.

The clear majority of these cables are unarmored, unguarded, small and relatively delicate – about the size of a garden hose. Isolated faults caused by natural phenomena, or even the occasional errant anchor, are usually not a problem because traffic is instantly rerouted to other cables. Still, accidents do happen. In 2011, a 75-year-old woman shoveling for shoreline copper severed a cable and took down internet access in Armenia for five hours.

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Sabotage!

This brings us to the first of our internet crash scenarios – the deliberate sabotage of undersea cables, either by terrorists or (more likely) military forces. In early 2017, NATO officials publicly disclosed that Russian submarines had dramatically increased activity around undersea data cables connecting Europe and North America.

"We are now seeing Russian underwater activity in the vicinity of undersea cables that I don't believe we have ever seen," U.S. Navy Rear Adm. Andrew Lennon, commander of NATO's submarine forces, told the Washington Post. "Russia is clearly taking an interest in NATO and NATO nations' undersea infrastructure."

If Russia were to sever all or most of the cables in the Pacific and Atlantic in a coordinated strike, the move wouldn't quite crash the internet. But it would essentially isolate America and, more to the point, disrupt communications between the U.S. and European NATO allies.

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Glitch!

Nefarious human activities aren't the only potential risk to the internet. (Although they are the scariest, more on that in a bit.) In 2015, a committee within the nonprofit organization ICANN issued a rather alarming report concerning a potential weakness buried deep in the internet's underlying structure.

According to the committee report, a vulnerability in the internet's address book system could potentially magnify the effect of any physical disruption to root servers or undersea cables. Ironically, the dilemma is keyed to the central strength of the internet – redundancy. If a significant portion of the internet were to go down for several days, the “backup system” of redundant paths could get terminally confused, mixing up new data with out-of-date information. The details get pretty complex. If you speak high-end engineering, you can read the original report.

And if these root servers were to be deliberately disabled, well – then things get very grim.

“The most interesting way to crash the internet is to focus on the 13 top-level root servers that ultimately help us find computers by name on the internet,” says Dr. Patrick Juola, computer science professor at Duquesne University and author of Principles of Computer Organization and Assembly Language. “If those computers could be disabled – whether by a power outage, a virus, or physical damage – most computers would not be able to find each other to send messages. In practical terms, the internet would simply stop working.”

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Solar flare!

Surely the most dramatic of all the potential internet doomsday scenarios, the possibility of a massive solar flare has kept experts up nights for several decades. Solar flare concerns predate the internet, actually. Science has long known that a major solar flare could produce an electromagnetic pulse (EMP) that could, theoretically, fry all electronics on the planet.

“A sufficiently powerful solar flare could produce an electromagnetic pulse that would shut down most of the computers in the world,” Juola says. “While some systems are protected against EMPs, any human-built protection is only so strong, and the sun can be a lot more powerful.”

Levinson concurs, and adds that other threats might descend from the heavenly firmament as well. “With all of our technological prowess, we still have not in any way mastered or even uncovered all the forces at work in the universe,” he says. “We don't know all the things that can go wrong.”

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The evil genius scenario

Even if we set aside natural disasters, cosmic blasts and coding glitches, we still have at least one other major threat to worry about. This is the scenario that is most popular in sci-fi films, high-tech thrillers, and pop culture in general. What if a hacker or group of hackers – state-sponsored or otherwise – actually figured out a way to disable the entire internet? What if someone develops a brand-new kind of virus, a chunk of mutant code that we can't even imagine at this point? Levinson calls it the Evil Genius problem. 

“Now this is highly unlikely, but it's not impossible,” Levinson says. “But there is always a chance that some devious hacking group figures out a way to bring down the internet and all the backup systems that provide redundancy.”

Once again, conventional wisdom tells us that there is simply no way this could happen; that the very architecture of the internet would prevent such a viral doomsday event. But a bedrock principle of computer security, Levinson says, is that you never say never. And you always prepare for the worst.

“Look, my best guess is that, at this point, no one knows how to bring down the whole internet, or even any significant part of it,” he says. “But it's foolhardy not to speculate about what could happen. The very process of speculation can reveal weaknesses in the system.”

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Systems theory

That brings us back to the realm of systems theory, and the enduring truism that no network is ever 100 percent secure. We simply cannot foresee all the variables. If the dark day comes when the internet does experience a global crash, the thing that takes it down will be, almost by definition, the thing we didn't see coming.

“It's possible, but very unlikely, for the entire internet to go down,” Juola says. “Just as it's possible to flip a coin fifty times and have it come up heads each time. The odds against that are roughly 2^50 to one, but it's possible.”

Levinson suggests another analogy: “The lesson of the Titanic is still valid today,” he says. “This was a ship that was specifically built to be unsinkable. All the scientists and experts of the time agreed. But they didn't think of everything and an iceberg hit it in just the wrong place at just the wrong time.

“The same is true of the internet. The thing that can take down an unbreakable system is the thing we don't see coming; that we haven't thought about. That principle never changes.”