ARLINGTON, VA. -- Security researchers announced on Thursday the release of a network sniffing tool that conveniently categorizes the data leaked by laptops and other devices during routine operation.

The tool, dubbed Ferret, analyzes information that computers and other network devices regularly send out as a matter of course--a problem that Robert Graham, CEO of startup Errata Security, called data seepage. Ferret captures and analyzes the administrative parts of 25 different protocols--such as the Simple Mail Transfer Protocol (SMTP), the Common Unix Printer Service (CUPS), and Apple File Protocol (AFP)--to glean information about the target computer and its user.

For example, a computer searching for a wireless connection will name all the access points to which it recently connected. As a computer's user roams the Web, the machine's Internet browser reveals a ream of information, including the computer's operating system, patch level of the browser and, of course, destinations.

The information could be used to develop a profile on the target and demonstrates that the protocols leak significant information, Graham told attendees at the Black Hat DC Conference.

"As you use this tool, you will see how much information you are leaking," he said. "Knowing this leads to obvious conclusions about what you need to do to protect yourself."

Network sniffers are old hat. Ferret's value is in the ability to organize the information, use only the protocol headers and filter out duplicate data, Graham said. The information, while seemingly innocuous by itself, can paint a detailed picture for an attacker, he said.

Errata Security plans to release Ferret and the tool's source code on its Web site. David Maynor, who released information about Apple flaws earlier in the conference, is also a founder for Errata Security.