CBO confirms breach of its computer systems

The Congressional Budget Office confirmed Thursday that its computer systems were breached, saying the agency has taken steps to contain the incident and implemented additional monitoring and security controls as investigators work to determine the scope and origin of the intrusion. The attack threatened to expose sensitive government data handled by the small nonpartisan office that provides lawmakers with cost estimates and analyses used throughout the federal budget and legislative process.

Caitlin Emma, a CBO spokeswoman, said in a written statement that the agency identified the security incident, took immediate action to contain it, and implemented additional monitoring and new security controls to further protect its systems. She added that the agency is investigating the matter and that work for Congress continues.

U.S. officials with knowledge of the inquiry told investigators the intrusion was believed to be conducted by a suspected foreign actor and that hackers may have accessed emails and internal chat logs. The CBO declined to confirm the attribution. Agency officials emphasized that the CBO, like other government entities and private organizations, faces ongoing...