Netscape Communications patched a security hole in its Web browser that made computers vulnerable to file theft. In response to the bug, reported last week, the AOL division posted a patch in a minor point upgrade, version 4.75, of its Netscape browser to its download site. The bug, dubbed Brown Orifice, concerns Netscape's implementation of Java. Without today's patches, Netscape lets an unsigned Java applet read and distribute files by acting as a Web server.