Cyber defenders sound the alarm as F5 hack exposes broad risks

A more than year-long digital intrusion into cybersecurity company F5, publicised last week and blamed on Chinese spies, has defenders across the industry hunting for signs of compromise among the many corporate networks that use its products.

Several worry that more disclosures are coming.

So far, little is known about the scope of the hack beyond statements from F5 that its source code and sensitive information about software vulnerabilities were stolen.

The company’s website says it serves more than four in five Fortune 500 companies in some…