The attack is apparently ongoing. In an advisory, Microsoft urged impacted customers to “close or change credentials for all compromised accounts.” U.S. intelligence agencies became aware of the incursion in February, around the same time that a Chinese spy balloon was downed, the New York Times reported. The infiltration was focused on communications infrastructure in Guam and other parts of the U.S., the Times reported, and was particularly alarming to U.S. intelligence because Guam sits at the heart of an American military response in case of a Taiwanese invasion.
Volt Typhoon is able to infiltrate organizations using a unnamed vulnerability in a popular cybersecurity suite called FortiGuard, Microsoft said. Once the hacking group has gained access to a corporate system, it steals user credentials from the security suite and uses them to try to gain access to other corporate systems. The state-sponsored hackers aren’t looking to create disruption yet, Microsoft said. Rather, “the threat actor intends to perform espionage and maintain access without being detected for as long as possible.” Infrastructure in nearly every critical sector has been impacted, Microsoft said, including the communications, transport, and maritime industries. Government organizations were also targeted.