More action needed to protect critical undersea cables from sabotage, Congress told

The United States and allies need a comprehensive strategy to shore up critical undersea cables, monitor them for adversarial threats and deter foes who would sever these information lifelines, experts told a joint hearing of the House Homeland Security subcommittees on Cybersecurity and Infrastructure Protection and Transportation and Maritime Security on Thursday.

More than 800,000 miles of undersea cables stretch across the oceans, hundreds of conduits for data (up to 99% of the world’s internet traffic, the EU reports) or renewable energy. The United States has more subsea cable landings than any other country — nearly 100.

There are as many as 200 incidents that damage these cables each year, the EU says. The top culprit is fishing vessels, which accidentally can damage cables through dragging anchors or trawling for fish. Natural occurrences such as seismic activity or wear-and-tear can also damage cables.

But anchors and other means can also be used to intentionally sabotage cables. Earlier this year, Chinese researchers from state-affiliated institutions claimed that they developed a powerful new tool capable of cutting undersea cables at record depths.

“If cables are abundant and repairs are swift, the impact of any incident is limited,” Alex Botting, senior director for global security and technology strategy at Venable, told the subcommittees in prepared remarks. “This, in turn, significantly reduces the incentive for our adversaries to engage in sabotage. Accordingly, we should pursue more efficient and transparent approvals processes for laying and repairing subsea cables, while of course maintaining high security standards.”

Botting also stressed that, currently, investigations into incidents that affect subsea cables are not sufficient.

“Roughly 70% of subsea cable disruptions are caused by human activity. Yet, in almost all cases we fail to investigate negligence or malicious intent,” he said. “If we believe that our adversaries may intend to engage in sabotage, we must develop the means to distinguish between accidental and intentional disruption and proactively investigate human-induced disruptions.”

Botting recommended that the Department of Homeland Security serve as a single point of contact and manage intelligence sharing for government and industry, and should collaborate with the latter “to conduct a comprehensive mapping of the submarine cable supply chain to identify potential choke points or areas of reliance on untrusted vendors and ensure that appropriate risk mitigations are in place.” These cables should also be designated as a critical infrastructure sector, he said.

Kevin Frazier, AI innovation and law fellow at The University of Texas School of Law, told lawmakers that “a robust undersea cable system is an essential part of achieving the nation’s AI aspirations and, therefore, a target of adversaries also in pursuit of AI dominance,” and a failure in the undersea cable system could have significant economic, political and technological consequences.

“There is no backup plan,” Frazier said in prepared remarks. “If all or even a significant number of the 20 or so cables connecting Europe to North America were disrupted, for example, satellites would not serve as a viable alternative. Internet traffic travels drastically slower via satellites. The satellite network also has significantly less bandwidth.”

Frazier recommended construction of 10 new cable repair ships for use by U.S. allies, deploying 100 undersea drones to assess and help maintain the cable system and laying/retrofitting 100,000 miles of undersea cables. As a second prong of the strategy, he urged “immediate adoption of policy strategies that deter bad actors from attacking the undersea cable system.”

“Aerial drones have already transformed terrestrial conflicts by lowering the cost of destruction. Iranian advances and their willingness to pass technology along to non-state actors suggests the same may be true in the undersea domain — to the extent it is not already,” he continued. “The United States should respond by developing similar AUVs and UUVs … while also increasing its enforcement capabilities and punishments in the short run.”

Matthew Kroenig, senior director at the Scowcroft Center for Strategy and Security at the Atlantic Council, emphasized that “China’s and Russia’s threats to subsea cables present a serious challenge to the global communications and energy systems that underpin U.S. and allied security, prosperity and way of life.”

“China seeks to dominate the digital infrastructure of the 21st century, including in subsea cables, to provide it with economic, espionage, military and geopolitical advantages,” he told the subcommittees in prepared remarks. “China and Russia wage gray-zone warfare to coerce vulnerable U.S. allies and partners and to induce caution in Washington about intervening on their behalf.”

As examples, Kroenig noted the severing of a key cable in the Baltic Sea last Christmas that prompted Finnish special forces to seize control of a Russian shadow fleet oil tanker, and Taiwan’s Matsu Islands being knocked offline in 2023 after Chinese-registered vessels cut two undersea cables.

“Currently, the U.S. and its allies lack a coordinated and effective strategy to deal with this threat,” he said, advocating a three-pillared plan that focuses on developing more resilient subsea cable infrastructure, increasing monitoring and patrols around vulnerable cables, and finding “creative ways to impose costs on states that attack subsea cables as a tool of statecraft and those who help them carry out attacks.”