Changes to Yahoo articles highlight quiet Internet danger

SAN JOSE, Calif. -- The dangers of Internet worms and viruses are well known, but security experts are warning of a more pernicious and potentially more damaging kind of attack -- the manipulation of content on trusted Web sites.

The issue became clear with the recent revelation that a hacker had rather easily entered Yahoo news pages and inserted phony quotes and wrong information on stories.

The hacker, 20-year-old Adrian Lamo of San Francisco, says he wanted to show Yahoo! Inc. that it needed to fix what he considers a basic mistake in its network setup. Yahoo says it has taken steps to solve the problem.

The incident highlights how vulnerable the Internet could be as a tool for quickly spreading misinformation.

Yahoo, which claims to have 200 million registered users, is one of the Internet's most popular sources of information. The company aggregates information from several news providers.

"A lot of attention has been given to the fact that data is stolen, but not necessarily that the integrity has been altered," said Elias Ladopoulos, a former hacker.

Yahoo released a statement saying it had taken "appropriate steps to block unauthorized access to help ensure that we maintain a secure environment."