By Raphael Satter

WASHINGTON (Reuters)

A significant amount of Americans' metadata has been compromised in a vast cyberespionage campaign by a Chinese hacking group known as "Salt Typhoon," according to a senior U.S. official who spoke to journalists on Wednesday.

The official, who remained anonymous, did not disclose specific numbers but emphasized that China's access to American telecommunications infrastructure is extensive and that the hacking activities are ongoing.

> "We believe a large number of Americans' metadata was taken," the official stated. When asked if this could include records from every American cell phone, the official clarified, "We do not believe it's every cell phone in the country, but we believe it's potentially a large number of individuals that the Chinese government was focused on."

Dozens of companies globally have been targeted by the hackers, with at least eight telecommunications and infrastructure firms in the U.S. affected.

U.S. officials have previously accused the hackers of targeting major firms like Verizon, AT&T, T-Mobile, and Lumen. T-Mobile asserted that no customer data was compromised, while Lumen indicated no evidence of customer data access on its network. However, in some instances, the hackers reportedly obtained telephone audio intercepts and a significant amount of call record data.

What is Call Record Metadata?
Call record metadata includes details such as who made a call, who received it, the duration, and location but excludes the conversation content. Even without the actual call content, bulk-captured metadata can provide an in-depth view of a person's life, work, and personal relationships.

The official noted that the White House has prioritized addressing the Salt Typhoon hackers, with President Joe Biden receiving multiple briefings regarding the intrusions.

The press call coincided with a classified briefing for all senators about the Salt Typhoon group’s efforts to compromise U.S. telecommunications companies.

Participants in the closed-door briefing included the FBI, Director of National Intelligence Avril Haines, FCC Chair Jessica Rosenworcel, the National Security Council, and the Cybersecurity and Infrastructure Security Agency.