US Treasury says Chinese hackers stole documents in 'major incident'

Chinese state-sponsored hackers breached the U.S. Treasury Department's computer security guardrails this month and stole documents in what Treasury called a "major incident," according to a letter to lawmakers, opens new tab that Treasury officials provided to Reuters on Monday.

The hackers compromised third-party cybersecurity service provider BeyondTrust and were able to access unclassified documents, the letter said.

According to the letter, hackers "gained access to a key used by the vendor to secure a cloud-based service used to remotely provide technical support for Treasury Departmental Offices (DO) end users. With access to the stolen key, the threat actor was able to override the service’s security, remotely access certain Treasury DO user workstations, and access certain unclassified documents maintained by those users."