Gen. Timothy Haugh, head of the National Security Agency, raised concerns about a Chinese hacking network "pre-positioning" critical infrastructure for future attacks, the Wall Street Journal reported.
Haugh said the Chinese hacking network Volt Typhoon aims to get into infrastructure, and lie in wait, waiting for the right moment to attack.
"We see attempts to be latent in a network that is critical infrastructure, that has no intelligence value, which is why it is so concerning," Haugh told the Journal. "One of the reasons we believe it is pre-positioning is — there are not tools being put down and there's not data being extracted."
Officials told the Journal that if China had a conflict with the U.S., it could launch cyberattacks against water supplies and power grids, the Journal said. China already infiltrated the water systems in Guam, a U.S. territory in the Western Pacific, Haugh told the Journal.
"It is very difficult to come up with a scenario where targeting a water supply for a civilian population ... is an appropriate target," Haugh said. "From a military perspective, it is inconsistent with how we would approach a proportional military necessity target."
Microsoft said Chinese hackers were developing capabilities to disrupt critical communications infrastructure between the U.S. and Asia during future crises, the Journal reported. The U.S. had previously disrupted a Chinese hacking operation in January.
Haugh said Chinese hackers subvert the identity of a user on the network, allowing them to then operate as a user and use tools inherent in the system they are targeting, a tactic known as living off the land. Chinese cyberattacks against the U.S. are growing consistently in number and sophistication, Haugh told the Journal.
According to leaked documents obtained by the Journal, the Chinese firm I-Soon claimed to have hacked into dozens of government targets, including ministries in Malaysia, Thailand, and Mongolia, and also universities in Hong Kong, Taiwan, and France.
China denies all accusations of cyberattacks and said the U.S. mounts its own cyberattacks.
Haugh told the Journal he works with defense contractors to stop China from stealing sensitive information.
"If they see a threat they can share it with us, and we do the same with them — every day across a thousand companies," Haugh said.