Chinese state-sponsored actors hacked into the Treasury Department in early December, accessing unclassified documents from its workstations, the agency said in a letter to lawmakers Monday.
The hackers stole a key from a third-party software service provider, BeyondTrust, and used it to override security and gain access to Treasury Department workstations, according to the letter, which was obtained by The Hill.
The agency is no longer using the compromised service, and there is no evidence the hackers still have access to Treasury Department information, it noted.
“Treasury takes very seriously all threats against our systems, and the data it holds,” the agency said in a statement.
“Over the last four years, Treasury has significantly bolstered its cyber defense, and we will continue to work with both private and public sector partners to protect our financial system from threat actors,” it continued.
The agency is working with the Cybersecurity and Infrastructure Security Agency, the FBI, the intelligence community and third-party investigators to examine the incident, according to Monday's letter.
It said it would supply lawmakers with additional information in 30 days — a requirement under current law for major cybersecurity incidents.
A spokesperson for Senate Banking Committee ranking member Tim Scott (R-S.C.) said in a statement that the senator has requested a briefing about the hack and is “closely monitoring the situation.”
Rebecca Beitsch contributed to this report.
Updated at 5:43 p.m. EST
