Mystery vandals are cutting fiber-optic cables in California – how worried should we be?

Somebody is cutting underground fiber-optic cables in Northern California.

The FBI said last month that it was investigating a rash of cable-cutting vandalism in the San Francisco Bay Area over the past year that resulted in loss of internet and phone service.

On Tuesday, 30 June, the 11th such case of vandalism cut off service for customers of Wave Broadband, near the state capital of Sacramento, which the internet service provider said was the result of a widespread “coordinated attack.”

Not so, according to the FBI, instead saying the most recent incident was confined to one area and not part of a coordinated attack.

The FBI branch in San Francisco also said there is “no indication these incidents are linked” to a case of vandalism in April 2013 that local law enforcement officials called “sabotage,” where a suspect cut fiber-optic cables, knocking out 911 service, and then fired a rifle at a PG&E power substation.

On the other hand, the 11 recent cases of cable-cutting do have enough similarities to make you wonder if they are related.

According to a report in USA Today, many of the incidents involved breaking into underground vaults to cut multiple cables, which would have required special equipment to enter the vaults and cut through protective sheathing on the cables.

The cables cut on Tuesday belong to Level 3 Communications and Zayo Group Holdings, two companies that own network “backbones,” which ISPs, cable and phone companies use to connect to the internet.

It took about five hours on Tuesday for the companies to fix the cables and restore service, but the FBI’s presence on the scene for its investigation slowed the repair efforts, according to the Wall Street Journal.

It’s not known how many customers lost service, but one big customer – Microsoft – reported on Tuesday that its Azure cloud service experienced “intermittent connectivity issues” in the Western and South Central US due to “fiber cuts in the Western US.”

FBI Special Agent Greg Wuthrich told USA Today that the vandalism was “disturbing,” and asked the public to come forward with tips:

When it affects multiple companies and cities, it does become disturbing. We definitely need the public's assistance.

The individuals responsible may appear to be “normal telecommunications workers,” or have special equipment equipment related to that job, the FBI said.

Yet the FBI is at a loss to explain the cable-cutting incidents of the past year and knows of “no real motive,” Ars Technica reported.

Just how vulnerable is the internet to this kind of sabotage?

The fiber-optic cables that carry the majority of the internet’s traffic are basically thin strands of glass that transmit data that is converted into light at one end of the cable and then converted back into data at the other end.

Cables are usually buried only a few feet underground and are small enough around – about the size of a finger – to be cut with scissors.

The California incidents impacted customers in multiple cities at a time, but it’s possible to knock out internet service to a much wider area with little more than a shovel.

In 2011, we reported on an incident that knocked out service to 90% of Armenia when a 75-year-old woman from Georgia struck a cable while digging for copper to sell.

To travel longer distances, internet traffic is carried by large undersea cables that are also vulnerable to accidental severing – by ship anchors or even shark bites.

In 2008, two major undersea cables were cut leading to widespread internet and phone outages across the Middle East – leading some to speculate that it was deliberate attack.

Losing internet service, even for a few hours, can cause big disruptions with big consequences.

Usually, when we think of the security of the internet we worry about defending against cyberattacks that could knock out financial, industrialgovernment or military networks.

We should also be thinking about how to protect the internet from physical attacks on its infrastructure.

Image of internet cable courtesy of Shutterstock.

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