"The Web," he said, "is rotten at its core."

Sandone, of Argus Systems Group Inc., isn't alone in his pessimism. Many believe that the Internet may be growing too fast for security to keep up with technology.

Some security experts believe it's time to focus on making the Net safer, which could mean rebuilding much of the underlying infrastructure from scratch. After all, consumers and businesses now use the Internet for tasks unforeseen 30 years ago.

Security was an afterthought when Internet standards were developed by university thinkers and computer administrators, says Russ Cooper, who runs the NTBugtraq Web site devoted to security.

"This is now the foundation for billions of dollars worth of commerce," Cooper said. "It is inherently flawed because we don't check to see if what it's being used for is what it is intended for."

Yahoo!, Buy.com, eBay, ETrade and other prominent sites were paralyzed for hours at a time last week when hackers overloaded them with fake traffic.

The attacks followed several computer virus outbreaks last year — such as Melissa — which spread rapidly by taking advantage of functions that were designed to make Internet use friendlier.

And last month, a hacker stole credit card numbers from the Internet music retailer CD Universe, then released thousands of them on a Web site after the firm refused to pay $100,000 ransom.

"I fully expect the Internet to ultimately be safe and stable," said Stephen Gorrell, program manager for Norton Internet Security software. "However, in the period of record growth, it's not surprising new holes are discovered."

The Internet's developers could not have effectively countered threats to commerce because e-businesses did not yet exist, Gorrell said.

As the Internet grows, so do the numbers of hackers and potential victims. And hackers are becoming more sophisticated, with some even developing tools to automate their attacks.

Software companies, some critics say, contribute to the problems by releasing products that still have security holes.

"Each day, technology is changing," said Robert Ing, who handles electronic security for SBR International Inc. in Toronto. "There's a rush to get products out to market because it is a competitive marketplace. Sometimes, security is overlooked."

Steve Hunt, security analyst at Giga Information Group in Chicago, hopes the latest attacks will encourage companies to take security more seriously.

"We owe quite a debt of gratitude to hackers to show us where our pants have been down," he said.

Security and Internet experts differ on how far they need to go — and that itself is a problem. Some believe in completely updating equipment and software to reduce users' anonymity and improve authentication.

Phil Attfield, director of technical marketing at McAfee.com, said Internet security will eventually catch up with the wild-and-free developments on the Web.

"The approaches are going to have to become more formal rather than ad hoc," he said. "We've been getting there incrementally. That's the way technology is evolving."

But hacking will never completely disappear, said Keith Teare, the chairman and chief executive of RealNames. Vandals broke into RealNames' computers Wednesday, and the company had to warn some 20,000 customers that their credit card numbers might have been stolen.

"For every secure environment, there will be somebody prepared to try to break in," Teare said. "If they are clever enough, they will find holes."