The FBI has warned businesses to improve security practice in light of the spate of hacktivist attacks in recent years.
The attacks were sometimes motivated by grey-hat hackers who cracked websites to demonstrate security flaws.
Speaking at a panel at the RSA Conference in San Francisco, FBI cyber division chief Eric Strom said companies were "taking [the threat] too lightly".
"[Businesses] think these are just a bunch of kids fooling around. The reality is that it can destroy a business. The FBI has put a lot of resources toward this problem. We don't look at it as a small issue."
The FBI has attempted to create collaborative efforts among enterprises that have been attacked so they may share threat intelligence.
PayPal had earlier called for industry collaboration to track down grey-hat hackers belonging to the AntiSecurity movement.
Grady Summer, a vice president at incident response firm Mandiant said groups like Anonymous were "helping the security cause by bringing it to the media and bringing those takedowns to light". "Companies are now becoming aware and worried."
Sharing cyber intelligence and the notion of seeking information from working groups and other security organisations has been a recurring discussion at the RSA conference.
Experts said businesses would be better prepared if they were educated in threat prevention and management.
The panel also flagged the issue of accountability of hacker groups.