It could take a year to secure the risk of "high exposures" of personal information on the federal Obamacare online exchange, a cybersecurity expert told CNBC on Monday.

"When you develop a website, you develop it with security in mind. And it doesn't appear to have happened this time," said David Kennedy, a so-called "white hat" hacker who tests online security by breaching websites. He testified on Capitol Hill about the flaws of HealthCare.gov last week.