The product stores raw content or supporting code under the web document root with an extension that is not specifically handled by the server.
If code is stored in a file with an extension such as ".inc" or ".pl", and the web server does not have a handler for that extension, then the server will likely send the contents of the file directly to the requester without the pre-processing that was expected. When that file contains sensitive information such as database credentials, this may allow the attacker to compromise the application or associated components.
Perform a type check before interpreting files.
Do not store sensitive information in files which may be misinterpreted.