A security hole in Adobe Systems Inc software, used to distribute movies and TV shows over the Internet, is giving users free access to record and copy from Amazon.com Inc’s video streaming service.

The problem exposes online video content to the rampant piracy that plagued the music industry during the Napster era and is undermining efforts by retailers, movie studios and television networks to cash in on a huge Web audience.

“It’s a fundamental flaw in the Adobe design. This was designed stupidly,” said Bruce Schneier, a security expert who is also the chief security technology officer at British Telecom.

The flaw rests in Adobe’s Flash video servers that are connected to the company’s players installed in nearly all of the world’s Web-connected computers.

The software doesn’t encrypt online content, but only orders sent to a video player such as start and stop play. To boost download speeds, Adobe dropped a stringent security feature that protects the connection between the Adobe software and its players.