Malware used frequently in cyberattacks against the United States over the past decade has been linked to the Chinese government, according to a new Department of Homeland Security report.

DHS’s Cybersecurity and Infrastructure Security Agency alerted business owners and government officials this week that much of the malware, or software designed to damage a computer or network, planted in attacks on digital networks and devices was used by authorities in China. CISA said its counterparts at the Pentagon and the FBI contributed to the discovery of who was involved in the attacks, though it did not reveal the number or identities of U.S. victims.