Chinas Hacking Reached Deep Into U.S. Telecoms

China’s recent breach of the innermost workings of the U.S.telecommunications system reached far deeper than the Biden administration has described, the chairman of the Senate Intelligence Committee said on Thursday, with hackers able to listen in on telephone conversations and read text messages.“The barn door is still wide open, or mostly open,” the Democratic chairman, Senator Mark Warner of Virginia, a former telecommunications executive, said in an interview on Thursday.Mr.

Warner said he had been stunned by the scope and depth of the breach, which was engineered over the past year by a group linked to Chinese intelligence that has been named Salt Typhoon by Microsoft, whose cybersecurity team discovered the hack in the summer.Government officials have been struggling to understand what China obtained and how it might have been able to monitor conversations held by a number of well-connected Americans, including President-elect Donald J.

Trump and Vice President-elect JD Vance.At first, the F.B.I.and other investigators believed that China’s hackers used stolen passwords to focus mostly on the system that taps telephone conversations and texts under court orders.

It is administered by a number of the nation’s telecommunications firms, including the three largest — Verizon, AT&T and T-Mobile.But in recent days, investigators have discovered how deeply China’s hackers had moved throughout the country by exploiting aging equipment and seams in the networks connecting disparate systems.U.S.

officials said that since the hack was exposed, the Chinese intruders had seemingly disappeared, suspending their intrusion so their full activity could not be discovered.But Mr.

Warner said it would be wrong to conclude that the Chinese had been ousted from the nation’s telecommunications system, or that investigators even understood how deeply they were embedded.“We’ve not found everywhere they are,” Mr.Warner said.The committee has received bri...