U.S. officials are privately delivering an unusual warning to telecommunications companies: Undersea cables that ferry internet traffic across the Pacific Ocean could be vulnerable to tampering by Chinese repair ships. State Department officials said a state-controlled Chinese company that helps repair international cables, S.B. Submarine Systems (SSB), appeared to be hiding its vessels’ locations from radio and satellite tracking services, which the officials and others said defied easy explanation.

The warnings highlight an overlooked security risk to undersea fiber-optic cables, according to these officials: Silicon Valley giants, such as Google and Meta Platforms, partially own many cables and are investing in more. But they rely on specialized construction and repair companies, including some with foreign ownership that U.S. officials fear could endanger the security of commercial and military data.

Hundreds of thousands of miles of underwater fiber-optic cables carry almost all the world’s international internet traffic. Dozens of lines lace the Pacific Ocean floor, shuttling data between the Americas, Asia and many island chains. SBSS is part of a regional consortium of companies that provides ships to fix undersea cables, including some belonging to major U.S. companies, by winching them to the surface, resplicing broken fibers that carry internet data and returning the lines to the sea floor… Underwater cables are vulnerable to tampering when they are brought to the surface for repairs, U.S. officials say. Tapping global data flows is still far easier on land, industry experts say. But at-sea repair could still offer an opportunity to install a device to remotely disable a cable or to study the technology in advanced signal repeaters installed by other companies.

SBSS was formed in 1995 as a Chinese-British joint venture. State-owned China Telecom has long held 51% of the business and is in the process of buying the remainder from U.K.-based Global Marine Systems, according to people familiar with the matter. A member of the Chinese Communist Party serves on the SBSS management team, according to the company’s website.

Safeguarding underwater cables has been a focus of U.S. national-security officials since the Cold War, when fears of Soviet espionage were paramount. In the 1970s, the U.S. secretly placed wiretaps on underwater Soviet lines in an intelligence coup known as Operation Ivy Bells….

SubCom, a U.S. cable ship company owned by private-equity giant Cerberus Capital Management, receives $10 million in annual U.S. government payments for participating in the Cable Security Fleet, a program partly overseen by the Pentagon…

Overall, cable owners have few choices with regard to repairing damaged undersea cables, as most repairing is done by an aging fleet of roughly 50 ships around the world…

Excerpts from U.S. Fears Undersea Cables Are Vulnerable to Espionage From Chinese Repair Ships, WSJ, May 19, 2024