China-linked hackers accessed over 400 US Treasury computers

The US Treasury Department announced in a letter back in December that it had been the , attributing it to a “China state-sponsored Advanced Persistent Threat actor.” Now we know more about the extent of the hack, .

The hacking group got into more than 400 laptop and desktop computers, many of which focused on “sanctions, international affairs and intelligence.” They also accessed employee usernames and passwords, in addition to more than 3,000 files on unclassified personal computers. These documents included travel data, organizational charts, sanction materials and foreign investment metrics.

An agency report indicates that the perpetrators likely stole a whole lot of this data, but were unable to get into the Treasury’s classified or email systems. The hackers did access materials regarding investigations run by the Committee on Foreign Investment. This committee reviews security implications surrounding real estate purchases and foreign investments in the US.

The agency report also notes that there wasn’t any evidence to suggest that the hackers tried to hide in the Treasury’s systems for the purpose of long-term intelligence gathering, and they didn’t leave behind any malware.

Investigators have attributed the intrusion to a notorious Chinese state-sponsored hacking group called Silk Typhoon, Halfnium or UNC5221. It has been suggested that they performed the hack outside of normal working hours to avoid detection. Last month, a spokesperson for the Chinese Foreign Ministry called the accusation that the attack was state-sponsored

Counterintelligence officials are still in the midst of a “comprehensive damage assessment” but Treasury employees are set to brief the Senate Committee on Banking, Housing and Urban Affairs on the matter this week.