Cybersecurity firm F5 Networks says government-backed hackers had “long-term, persistent access” to its network, which allowed them to steal the company’s source code and customer information.In a filing with the U.S. Securities and Exchange Commission on Wednesday, F5 said it now “believes its containment actions have been successful,” after first discovering the hackers in its network on August 9. The Seattle, Washington-based company, which specializes in providing application security and cybersecurity ...