Sometimes you need a voice from outside to know what's missing within

“We knew there was an incident in 2006,” he told Threat Level. “But it was inconclusive at the time as to whether or not actual code was taken or that someone had actual code in their hands.”

Following the public claim of hackers earlier this month that they had source code for pcAnywhere, Norton Utilities and other products, Paden said the company went back through its logs and records and “put 2 and 2 together that there was a source code theft.”

via wired.com

Symantec waited for 7 long years and hackers to trash them publicly before investigating and putting "2 and 2" together and we all trusted them for securing us.