House lawmakers investigating suspected China-linked hack of sensitive AT&T, Verizon systems

House lawmakers said Friday they are investigating a China-linked hack of major American telecommunication companies, including AT&T, Verizon and Lumen Technologies.

The House Select Committee on the Chinese Communist Party is looking into the “Salt Typhoon” hacking group suspected of breaching systems used by the companies to cooperate with court-approved wiretapping.

Panel Chairman John Moolenaar, Michigan Republican, and Illinois Rep. Raja Krishnamoorthi, the select committee’s ranking Democrat, wrote a letter on Thursday to the companies’ executives demanding information on the hack and recommendations for the federal government.

“While we appreciate that there may be an ongoing federal investigation into this matter, and we appreciate your cooperation with any such inquiries, we cannot wait to fortify our defenses,” the committee leaders wrote. “Accordingly, we respectfully request a closed-door briefing from appropriate representatives of each of your companies regarding the reported Salt Typhoon breach.”

The National Security Agency is among the federal agencies working to learn more about the China-linked hack.

Air Force Gen. Timothy Haugh, NSA director, told reporters at a security conference on Oct. 6 in Georgia that NSA officials were in the early days of an investigation. Gen. Haugh said it was premature to talk then about the specific case, according to NBC.

Asked on Wednesday about the Salt Typhoon hackers’ actions, NSA Cybersecurity Director Dave Luber said China has been known to use security vulnerabilities to gain access to systems around the world, particularly in the U.S.

“If you’re going to have a cyber program where you start in mainland China and find your way to a target, you’re going to have to use a number of different parts of the internet ecosystem, including telecommunications systems, in order to gain access,” Mr. Luber said at a Recorded Future conference.

Details of the China-linked hackers’ access inside AT&T, Verizon, and Lumen Technologies are not publicly known.

AT&T and Lumen Technologies declined to comment on Friday, while Verizon did not respond to questions.