Google has released the source code for its internal RatProxy security tool.

The software analyses web pages for potential security risks and reports back to the site administrator.

RatProxy can pick up cross-site scripting flaws and incomplete cross-site defence mechanisms, as well as potential data leak sources and risky code that retrieves data from outside domains.

Google hopes that developers will put the tool to use when coding new web-based services that rely on multiple sites and outside sources for data.

Michal Zalewski, a security engineer at Google, warned, however, that the tool should not be considered a substitute for a thorough analysis by a security professional.

"We feel it will be a valuable contribution to the information security community, helping to advance the understanding of security challenges associated with contemporary web technologies," he said.

"We believe that responsible security research brings a net overall benefit to the safety of the web as a whole, and have released this tool explicitly to support that kind of research."

Users can download RatProxy from the Google Code site. The tool works on Windows, Linux, FreeBSD and MacOS X operating systems.