If you've been following the events in Syria over the past few days, you know the country's Internet is now back from the dead after a 19-hour outage that the government blamed on "terrorist" sabotage--an explanation bought by approximately zero people.
But just because destroying the cables would be logistically and technically difficult for a terrorist or individual--not to mention suicidal; the voltage running through them would be enough to kill someone trying to cut through--doesn't make it unthinkable. In March, Egyptian authorities accused three men in a fishing boat of trying to sever a submarine cable connecting Alexandria to the Web. The evidence was thin and experts are as cynical about that incident as the latest service disruption in Syria. But both episodes draw attention to how exposed the world's Internet infrastructure really is.
Let's begin with how the cables are physically stabilized. They're not. The cables tend to rest unsecured on the ocean floor. Landslides, ship anchors--all are capable of moving or dragging the cables out of their normal position. Pull too hard, and they break. In 2006, an underwater landslide between Taiwan and the Philippines disrupted 19 out of 20 Internet cables in the area, causing service in much of Asia to go dark. Even though software could tell the repair crews exactly which part of the cables had malfunctioned, locating the actual point of the break took more time because the event had moved the cables and buried them.