Hack with confidence.
Page add-to-your-blog.php is vulnerable to at least the following:
Stored Cross-Site Scripting: Attempt to inject cross-site scripts which will be stored in the backend database. When a user visits this page, the cross-site scripts will be fetched from the database, incorporated into the HTML generated, and sent to the user browser. The user browser will execute the Javascript. One option is to inject a cross-site script which sends the user to the capture-data.php page. You can view captured data on the captured-data.php page.
Insufficent Transport Layer Protection: This page is vulnerable to interception with wireshark or tcpdump.
Application Log Injection: Some inputs on this page are recorded into log records which can be read by visiting the Show Log page. Vulnerabilities on the Show Log page may allow injections in log records to execute.
Method Tampering: Because the page does not specify that the input parameters must be posted, it is possible to submit input parameters via a post or a get. This is a second order vulnerability allowing other vulnerabilities to be exploited easier.
Cross Site Request Forgery: This page is vulnerable to cross-site request forgery. There are a few steps to prepare a cross-site script to carry out the cross-site request forgery. Begin by filling out the form capturing the legitimate request. Inject a stored or reflected cross-site script anywhere on the site that will cause the browser to submit a copy of the legitimate request to the server. The server will process the request as if the user had filled out the form themselves.
Javascript Validation Bypass: Set the page to at least security level 1 to activate the javascript validation. Javascript validation can always be bypassed. Use a client-proxy like Burp-Suite to capture the request after it has left the browser. You can alter the request at that time. Also, Javascript can be disabled.
HTML Injection: It is possible to inject your own HTML into this page because the input is not encoded prior to be used as output. Determine which input field contributes output here and inject HTML, CSS, and/or Javascripts in order to alter the client-side code of this page.
SQL Injection with SQLMap: This page contains an sql injection vulnerability. The SQLMap tool may be able to automate testing and confirming this vulnerability.
SQL Injection: Attempt to inject special database characters or SQL timing attacks into page parameters. Database errors, page defacement, or noticable delays in response may indicate SQL injection flaws. This page is vulnerable.
Reflected Cross-Site Scripting: This page is vulnerable to reflected cross-site scripting because the input is not encoded prior to be used as output. Determine which input field contributes output here and inject scripts. Try to redirect the user to the capture-data.php page which records cookies and other parameters. Visit the captured-data.php page to view captured data.