The Internet was designed to be robust, fault-tolerant and distributed, but its technology is still in its infancy.
The fact that the Web has not stopped functioning in its initial decades sometimes encourages us to assume that it never will. But like any system, biological or man-made, the Internet has the potential to fail.
Monday's "DNSChanger" malware problem, which affected some 200,000 computers, was much hyped and ultimately inconsequential. But here are four maladies that really do have the potential to wipe out Internet access on a massive scale.
1. Space weather
When you think about Web surfing, you probably don't worry about what's happening on the surface of the sun 92 million miles away. But you should. Solar flares are one of our most serious threats for our communication systems.
Consider satellite failures. One afternoon in 1998, the Galaxy IV, a $250 million satellite floating 35,000 kilometers above the planet, suddenly spun out of control. The main suspect is a solar flare: the sun was acting up at that time, and several other satellites (owned by Germany, Japan, NASA and Motorola) all failed at the same moment.
The effects were instant and worldwide. Eighty percent of pagers instantly went down. Physicians, managers and drug dealers all across the United States looked down and realized they were no longer receiving pages. NPR, CBS, Direct PC Internet and dozens of other services went down. It is estimated that in recent years at least 12 satellites have been lost due to the effects of space weather.
But it's not just satellites that we have to worry about. When a massive solar flare erupts on the sun, it can cause geomagnetic storms on the Earth. The largest solar eruption recorded so far was in 1859. Known as the Carrington flare, it sent telegraph wires across Europe and America into a sparking frenzy.
Since that time, the technology blanketing the planet has changed quite a bit. If we were to get another solar flare of that size now, what would happen? The answer is clear to space physicists and electrical engineers: it would blow out transformers and melt down our computer systems. In a small disruption in 1989, an electromagnetic storm arrested power throughout most of Quebec and halted the Toronto stock market for three hours.
A major solar event could theoretically melt down the whole Internet. What earthquakes, bombs, and terrorism cannot do might be accomplished in moments by a solar corona.
Given our dependence on the communication systems of our planet, both satellite- and ground-based, this is not simply a theoretical worry. The next major geomagnetic storms are expected at the peak of the next solar sunspot cycle in mid-2013, so hang on tight.
Wars of the future will be fought less by rugged soldiers in the field and more by smart kids perched in front of computers slamming energy drinks. As our dependence shifts onto the Net, so do our vulnerabilities.
This future can already be detected in the tight relationship between corporeal conflicts and cyber attacks. When one examines the physical conflicts between India and Pakistan, the Israelis and Palestinians or the parties in the collapse of Yugoslavia, the escalation of real-world violence is immediately mirrored by cyber-space warfare.
The main targets in cyberwar are largely military targets, but increasingly large multinational corporations serve just as well. Take one of them down, even temporarily, and you have done more damage to the economy of your enemy than scores of soldier deaths.
Since the beginning of the computer era, the 1960s, there have been computer viruses: programs that latch onto a host system to reproduce themselves and send out new copies. Just as in biology, as computers have evolved in sophistication, so have viruses co-evolved. And the cousins to the viruses, worms, do not even need a host system but can multiply themselves over networks.
Given the defenses in place, are these parasites only a minor theoretical concern? No. Consider the Stuxnet worm that raised its head in 2010. This worm zigzagged its way into Iranian industrial systems, reprogrammed them, hid its tracks and wrecked the factory operations. Seemingly coming from nowhere, Stuxnet introduced itself as a destructive, unstoppable herald of what's to come.
It will surprise no one that cyberwarfare of the future will involve targeting not only military and industrial targets but Internet connectivity for the general population. If you want to take down your enemy, start by shredding his Net.
3. Political mandate
In the face of the 2010 post-election riots in Iran, the government there shut down the Internet for 45 minutes, presumably to set up filtering of YouTube, Twitter and other sites. Egypt did the same during its revolution of early 2011. China is actively pursuing the capability to shut down its own Internet this way.
But it's not just countries like Iran and China that think about this kind of control over the Web. On June 24, 2010, a Homeland Security committee in the U.S. Senate approved a bill giving the president authority to wield an "Internet kill switch." The bill, Protecting Cyberspace as a National Asset Act (PCNAA), proposed to give the president "emergency authority to shut down private sector or government networks in the event of a cyber attack capable of causing massive damage or loss of life."
The "kill switch" provision was removed from the version of the cybersecurity bill that's before the current Congress.
It's probably just as well. Almost unanimously, Internet security analysts feel that shutting down the Web would inevitably do more harm than good, given our predicted level of dependency on it in time of war for news, communication with loved ones and crisis information aggregation.
Security guru Bruce Schneier identifies at least 3 problems with the shutdown idea. First, the hope of building an electronic line of fortifications is flawed because there will always be hundreds of ways for enemies to get around it. No nation or legal decree can plug all the holes.
The second major problem is that we will be entirely unable to predict the effects of such an attempted shutdown. As Schneier puts it: "The Internet is the most complex machine mankind has ever built and shutting down portions of it would have all sorts of unforeseen ancillary effects."