Individuals concerned about the privacy of their communications should consider using encrypted messaging apps and encrypted voice communications, CISA and FBI officials say.
Concerns over the extent of China-backed Salt Typhoon’s intrusions into US telecom networks have prompted the US Cybersecurity and Infrastructure Security Agency (CISA), the National Security Agency (NSA), and the FBI to issue guidance to the sector on addressing the threat.
The detailed recommendations come as officials from the authoring agencies this week described victims of the attack — which include Verizon, AT&T, and Lumen — as still working to eradicate the threat actor from their networks.
Telcos Still Working to Evict Chinese State Sponsored Hackers
“We cannot say with certainty that the adversary has been evicted, because we still don’t know the scope of what they’re doing,” Jeff Greene, executive assistant director for cybersecurity at CISA, said in a media call this week.
“I have confidence that we are on top of it in terms of tracking them down and seeing what’s going on, but we cannot, with confidence, say that we know everything,” Greene said, according to a transcript of the media call that CISA made available to Dark Reading. Given where most victims are in their investigations, it is “impossible” to predict a timeframe for when they will complete fully evicting the threat actor, he said.
Several security experts consider Salt Typhoon’s attacks on US telecom infrastructure as one of the most egregious cyber espionage campaigns ever in size and scope. It’s unknown how many companies the threat actor has compromised as part of the campaign so far, but known victims include some of the biggest telecom providers in the country, including AT&T and Verizon.
The attacks enabled multiple activities, including theft of a large number of call detail records — such as a caller’s and receiver’s phone numbers, call duration, call type, and cell tower location — of telecom customers. In a smaller number of instances, Salt Typhoon used its presence on telecom provider networks to intercept calls and messages of targeted individuals, which include government officials and politicians. Separately, the threat actor also collected information on an unknown number of individuals who were the subjects of legal national security and law enforcement intercepts.
“The continued investigation into the PRC targeting commercial telecom infrastructure has revealed a broad and significant cyber-espionage campaign,” an FBI official said on background during this week’s media call. “We have identified that PRC-affiliated cyber actors have compromised networks of multiple telecom companies to enable multiple activities.
