We all live under the assumption that the web is unbreakable. After all, it has thousands of different nodes and is so decentralized that there isn’t even as many as a handful of places that control the Internet. But does that mean that something couldn’t do enough harm to it to cripple it or bring it down?

Before I look at disaster scenarios, which certainly exist, there is one other thing to consider. The big global Internet as we think about it has probably already died. The Internet security firm Kaspersky reports that by the end of 2014 there were dozens of countries that had effectively walled themselves off from the global Internet. A few examples like China are well known, but numerous other countries, including some in Europe, have walled off their Internet to some degree in response to spying being done by the NSA and other governments.

So the question that is probably more germane to ask is whether or not there is anything that could bring down the US Internet for any substantial amount of time? In the US there are a handful of major hubs in places like Atlanta, Dallas, San Francisco, Northern Virginia, and Chicago. A large percentage of Internet traffic passes through these major portals. But there are also secondary hubs in almost every major city that act as regional Internet switching hubs, and so even if a major hub is disrupted somehow, these regional hubs can pick up a lot of the slack. Additionally, there is a lot of direct peering between Internet companies, and companies like Google and Netflix have direct connections to numerous ISPs using routes that often don’t go through major hubs.

But still, it certainly could be disastrous for our economy if more than one of the major hubs went down at the same time. Many people do not appreciate the extent that we have moved a large chunk of our economy to the Internet as part of the migration to the cloud. A large portion of the daily work of most companies would come to a screeching halt without the Internet and many employees would be unable to function during an outage.

There have been numerous security and networking experts who have looked at threats to the Internet and they have identified a few:

• Electromagnetic Pulse. A large EMP could knock out Internet hubs in ways that make them difficult to restart immediately. While it’s probably unlikely that we have to be too worried about nuclear war (and if we do, the Internet is one of my smaller worries), there is always the possibility of a huge and prolonged solar flare. We have been tracking solar flares for less than a century and we don’t really know that the sun doesn’t occasionally pump out flares much larger than the ones that we expect.
• Introducing Noise. It is possible for saboteurs to introduce noise into the Internet such that it would accumulate to make it hard to communicate. This could be done by putting black boxes into numerous remote fiber switching points that would inject enough noise into the system to garble the signals. If enough of these were initiated at the same time the Internet wouldn’t stop, but most of what is being sent would have enough errors to make it unusable.
• Border Gateway Hijacking. The border gateway protocol is the system on the Internet that tells packets where to go. If the BGP routers at major Internet hubs could be infected or hacked at the same time the Internet could lose the ability to route traffic.
• Denial of Service Attacks. DDoS attacks have become common and for the most part these are more of a nuisance than a threat. But network experts say that prolonged DDoS attacks from numerous locations directed against the Internet hubs might be able to largely halt other web traffic. Certainly nothing of that magnitude has ever been undertaken.
• Cyberwarfare. Perhaps the biggest worry in coming years will be cyberattacks that are aimed at taking down the US Internet. Certainly we have enough enemies in the world who might try such a thing. While the US government has recently beefed up funding and emphasis on defending against cyberattacks, many experts don’t think this effort will make much improvement in our security.

Perhaps one of the biggest issues we have in protecting against these various kinds of attacks is that there is no ‘Internet’ infrastructure that is under the control of any one company or entity. There are numerous firms that own internet electronics and the fibers that feed the Internet; most of these companies don’t seem to be making cybersecurity a high priority. I’m not even sure that most of them know what they ought to do. How do you really defend against an all-out cyberattack when you can’t know ahead of time what it might look like?

This isn’t the kind of thing that should keep us up all night worrying, but the threats are there and there are people in the world who would love to see the US economy take a huge hit. It certainly will not be surprising to see a few such attempts over the coming decades – let’s just hope we are ready for it.