U.S. telecom firm T-Mobile (TMUS.O) said on Wednesday it had detected attempts in recent weeks by "bad actors" to infiltrate its systems but they did not access sensitive customer data.
The statement followed reports about "Salt Typhoon," a Chinese-linked cyberespionage operation targeting U.S. telecommunications firms.
T-Mobile Chief Security Officer Jeff Simon said in a blog on the company's website Wednesday that the company detected attacks from an unnamed "wireline provider's network that was connected to ours."
T-Mobile's defenses protected customer information, prevented disruption of services and stopped the attack from advancing, he said.
Simon added that it was not clear who the hackers were, but the company reported its findings to the U.S. government for assessment. "Bad actors had no access to sensitive customer data (including calls, voicemails or texts)," Simon wrote.
A T-Mobile spokesperson said Wednesday that while the "traits" of the hackers who targeted T-Mobile were similar to Salt Typhoon, "we don't know it's them."
T-Mobile also cut the connection to the provider's network in the belief it was compromised, Simon wrote, without naming the provider.
Simon said he represented T-Mobile in a White House meeting last week to discuss "large-scale, sophisticated national threats."
The FBI and the Cybersecurity & Infrastructure Security Agency said in a joint statement this month that authorities were investigating a "broad and significant cyber espionage campaign" by Chinese-linked hackers.
The Chinese operation infiltrated AT&T (T.N), Verizon (VZ.N) and Lumen (LUMN.N), according to media reports.
The hackers stole customer call records, gained access to information that law enforcement sought under court order and compromised private communications for a "limited number" of people in government or politics, the statement said.
The operation gained access to phones of campaign staff for both Donald Trump and Kamala Harris before the Nov. 5 presidential election, according to reports.
The Wall Street Journal reported Nov. 15 that T-Mobile was also hacked.
