America is losing the war against hackers, an executive assistant director of the Federal Bureau of Investigation says.

Shawn Henry, who is getting ready to leave the bureau after more than two decades with the law enforcement agency, says the United States is falling behind in the ongoing fight against cyber ne'er-do-wells, ZDNet.com reported Wednesday.

"I don't see how we ever come out of this without changes in technology or changes in behavior, because with the status quo, it's an unsustainable model," Henry told The Wall Street Journal. "Unsustainable in that you never get ahead, never become secure, never have a reasonable expectation of privacy or security."

As hackers around the world increasingly target U.S. business and government Web sites, "we're not winning," Henry said.

FBI agents are constantly finding data stolen from companies who are not even aware their networks had been hacked, he said.

"We have found their data in the middle of other investigations," Henry said. "They are shocked and, in many cases, they've been breached for many months, in some cases years, which means that an adversary had full visibility into everything occurring on that network, potentially."

In its war against hackers the FBI is outnumbered, Henry said, with too many hackers around the world and too many entry points in the companies and government agencies the FBI wants to try to protect.