* Test by pasting internal url directly into browser address bar without login. Internal pages should not open.
* If you are logged in using username and password and browsing internal pages then try changing url options directly. I.e. If you are checking some publisher site statistics with publisher site ID= 123. Try directly changing the url site ID parameter to different site ID which is not related to logged in user. Access should denied for this user to view others stats.
* Try some invalid inputs in input fields like login username, password, input text boxes. Check the system reaction on all invalid inputs.
* Web directories or files should not be accessible directly unless given download option.
* Test the CAPTCHA for automates scripts logins.
* Test if SSL is used for security measures. If used proper message should get displayed when user switch from non-secure http:// pages to secure https:// pages and vice versa.
* All transactions, error messages, security breach attempts should get logged in log files somewhere on web server.