A small, bipartisan group of senators including Chris Murphy, D-Conn., have written to the secretaries of defense, state and homeland security, asking for information on "steps taken to enhance the security of our vital undersea network," after recent reports of Russian ships operating near undersea fiber optic cables.  

The majority of the world's telecommunications and Internet traffic flow through these cables, which are usually 1 to 2 inches thick.

"Undersea communication cables are responsible for moving trillions of dollars in global business, more than 95 percent of daily communications, and matters extremely significant to our national security," the senators' letter says. 

The senators are "increasingly concerned" about cables whose locations are well known and carry data important to our economy and military.

The first transatlantic cables were laid in the 1860s, according to Thomas Fedyszyn, a member of the Naval War College's Naval Security Affairs faculty and the college director of the Europe-Russia Studies Group.

The route they were laid on essentially became the main pathway for future cables, Fedyszyn said. 

"It's always been presumed that militaries will always have additional cables that will carry classified materials," Fedyszyn said by phone Wednesday.

The New York Times last month reported that "Russian submarines and spy ships are aggressively operating near the vital undersea cables that carry almost all global Internet communications."

"Maybe it's just a threat, but the Russians wouldn't be snooping around these undersea cables unless they are trying to send a message that they have the capacity to interrupt undersea communications," Murphy said in a prepared statement.

"The ultimate Russian hack on the United States could involve severing the fiber-optic cables at some of their hardest-to-access locations to halt the instant communications on which the West's governments, economies and citizens have grown dependent," The New York Times article says.

The "worst of all possible worlds" in this situation, according to Fedyszyn, is that the Russians "hack the cables without us knowing it."

If a cable gets cut, it's more clear what's happening, and we'd have to find other ways to get information, Fedyszyn said.

"A submarine is of course the perfect tool to do this stuff," he said.

The U.S. government considers the undersea cables "critical infrastructure." Generally speaking, the armed services are involved in the protection of critical infrastructure.

The Obama Administration's 2015 National Security Strategy states: "We are fortifying our critical infrastructure against all hazards, especially cyber espionage and attack."

"Drawing on the voluntary cybersecurity framework, we are securing Federal networks and working with the private sector, civil society, and other stakeholders to strengthen the security and resilience of U.S. critical infrastructure," the document goes on to say.

In their letter, the senators requested "information on what steps are being taken, and what steps need to be taken, in order to enhance the security of the undersea network on which the U.S. depends. We wish to discuss this matter further with you in a classified setting, while doing everything possible to allow the public to know we are taking every step to maintain their security."

As for the vulnerability of the cables, Fedyszyn said, "If found and the enemy wants them cut, I would say very vulnerable."

The biggest part of the vulnerability, he continued, is location, as in locating the cables.

Asked what he'd be thinking if he were a Pentagon official, Fedyszyn said, "I'm watching the Russian fleet."

One of his assignments during his 31-year naval career was as the U.S. Naval attaché to Russia.

Starting in 2008, Russia began to modernize its Navy, Fedyszyn said, "which really got very bad between 1990 and 2008."

He saw that firsthand when he was the attaché in Moscow.

In 2008, Russia "started to get money, started to get directed again," Fedyszyn said, and we're "just now beginning to see the modern ships coming off the shipways to include submarines," though still in small numbers.

"What we have to do, just like we did in the Cold War, is to watch their submarines," Fedyszyn said. "That's difficult work."

j.bergman@theday.com

Twitter: @JuliaSBergman