Security firm reveals Chinese spies infiltrated numerous public and private networks.

Chinese hackers, suspected to be state-backed, used a security hole in Barracuda Networks' Email Security Gateway to breach hundreds of public and private sector organizations globally, including nearly a third of government agencies. The hackers sent emails containing malicious file attachments to gain access to targeted organizations' devices and data. The majority of the impact was in the Americas, reflecting the geography of Barracuda's customer base. The breach was discovered in June, and Barracuda recommended fully replacing the appliances. The U.S. government has accused Beijing of being its principal cyberespionage threat.