The software 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.
Time of Introduction
Technical Impact: Read application
The following code uses an include file to store database
$dbName = 'usersDB';
$dbPassword = 'skjdh#67nkjd3$3$';
$db = connectToDB($dbName, $dbPassword);
If the server does not have an explicit handler set for .inc files it
may send the contents of database.inc to an attacker without
pre-processing, if the attacker requests the file directly. This will
expose the database name and password.