A security hole has been found in Google's beta Desktop Search which could allow someone to access people's result summaries and so discover the content of personal files.

Professor Dan Wallach and two graduate students at the University of Rice's computer sciences department discovered the flaw, and posted it on the university's Computer Security Lab website on Sunday. They describe it as "serious" and said it could allow attackers to read snippets of files embedded in Google's normal Web searches by the local search engine.

Google was notified of the flaw and has fixed it in an update that is currently being rolled out through an auto-update feature, the company said.

The Rice researchers said users can check if they have the updated version by selecting the "about" icon in their Google Desktop Search task bar. If it says version number 121004, indicating 10 December 2004, or later, they are safe.

To be affected, a user would have to visit a website where an attacker has embedded a particular Java applet. The applet makes certain network connections that trick Google Desktop into integrating a user's local search results with results from an online search. When users visit the compromised site, the applet reads their local search result summaries and sends them back to the attacker's server, they said.

Summaries from Google Desktop searches often contain snippets of content from personal files, and it is this content that the attacker is able to read, the researchers said.

Users on wireless networks can be attacked even if they are not visiting a compromised site, if the attacker tampers with the network connections being made by the user's Web browser, the researchers said. By doing this, the attack could be injected into any other Web page.

Google released a beta version of its desktop search product in October, allowing users to search PC files, local e-mail messages, and archived chat sessions. It joined an industry stampede into the local search space, with AOL, Yahoo and Microsoft all driving their searches onto the desktop.

Other desktop search products are not believed to have the flaw, however, since Google's is the only one which seamlessly integrates local search results with those of online searches, the researchers said.