Cross-site Scripting (XSS)

XSS is the insertion of malicious Javascript code in a webpage, that can steal your session cookie, or do something malicious (make the page do something else than it is meant to).

Now, the way you inject your javascript depends on that particular site. There is no mechanism involved, except than to going through the painful process of reading hundreds of lines of code on their client end and hoping that they made mistake. You can find XSS vulnerabilities by using trial and error method on small profile websites but for corporate websites, they are usually secured against such trial and error methods, that means you have to go through the source code and find the programming mistakes.

Definitely, XSS or Cross-Site Scripting is a hot topic. Sometimes, when I'm bored and have nothing to do (which usually doesn't happen too often), I start looking for websites and try to see if they have some kind of vulnerability. I do it just because I like to learn from others and helps me to understand how to protect my websites. Of course, I don't cause any problem or harm anyone, it is just for educational purposes. (Believe me, I'm being honest, lol)

However, it is not "super easy" to find vulnerabilities in websites, and if you want to learn how to work and apply XSS you should go to:  http://www.insecurelabs.org/

insecurelabs.org is an educational website which was build intentionally insecure for XSS, great, right!? So if you find XSS flaws, good for you.

Being on this website, you can start testing your scritps, For example, after the URL http://www.insecurelabs.org/ just add this script:

Search.aspx?Query=<script>alert('CSS Vulnerable - found it by BigBangCode')</script>

and hit enter key.

You'll see a dialog box with the text you entered. Of course, the website didn't mean to do that, but you just forced it to do it, feels good, right? lol

Other example,

Imagine you are somewhere in the internet and find this:

http://www.insecurelabs.org/Search.aspx?Query=%3Cscript%3Ewindow.open(%22http://bigbang-code.blogspot.com/%22)%3C/script%3E

at first sight, if you are not careful, just by looking at the first part of the URL (insecurelabs.org) you would think that the link will take you to that website. However, once you clicn on it, you will be redirected to my blog instead (look at the end of the URL). With this technique, taking advantage of this vulnerability we can redirect traffic to our website by fooling poeple. Easy, right?

Wait, wait we are not done, =)

Now, paste this code in your browser and hit enter key:


http://www.insecurelabs.org/Search.aspx?Query=%3Chtml+xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F1999%2Fxhtml%27%3E++++%3Chead+%3E+++++++%3Cmeta+http-equiv%3D%27Content-Type%27+content%3D%27text%2Fhtml%3B+charset%3Dutf-8%27%2F%3E+++++++%3Ctitle+%3EPlease+let+me+steal+your+private+information%3C%2Ftitle%3E++++%3C%2Fhead%3E+%3Cbody%3E+%3Ch1%3EPlease+let+me+steal+your+private+information%3C%2Fh1%3E+++%3Cform+id%3D%27sampleform%27+method%3D%27post%27+action%3D%27%27+%3E++++%3Cp%3E++++Name%3A+%3Cinput+type%3D%27text%27+name%3D%27Name%27+%2F%3E++++%3C%2Fp%3E++++%3Cp%3E++++Email%3A+%3Cinput+type%3D%27text%27+name%3D%27Email%27+%2F%3E++++%3C%2Fp%3E++++%3Cp%3E++++pass%3A+%3Cinput+type%3D%27text%27+name%3D%27pass%27+%2F%3E++++%3C%2Fp%3E++++%3Cp%3E++++SSN%3A+%3Cinput+type%3D%27text%27+name%3D%27ssn%27+%2F%3E++++%3C%2Fp%3E+++++%3Cp%3E++++%3Cinput+type%3D%27submit%27+name%3D%27Submit%27+value%3D%27Submit%27+%2F%3E++++%3C%2Fp%3E+%3C%2Fform%3E+++%3C%2Fbody%3E+%3C%2Fhtml%3E

Voila!!... It looks like the webiste has some page with a form that we can fill out with our private and critical information. Of course, it is FAKE!, Some people would think is real because seems to be part of insecurelabs.org . That is why it is so important to look at the URL and make sure we are providing our information to only secure websites. Do we see any "https"? or does it look legit or real? why this website is asking for SSN or credit card info? Alsways ask those kind of questions when sunrfing the internet.

Even if you have 200 years of experience with computers, if you do not have common sense, you can be a victim of cybercrime.

Spring Framework - MVC Architecture

The Spring web MVC framework provides model-view-controller architecture and ready components that can be used to develop flexible and loosely coupled web applications. The MVC pattern results in separating the different aspects of the application (input logic, business logic, and UI logic), while providing a loose coupling between these elements.

• The Model encapsulates the application data and in general they will consist of POJO.
• The View is responsible for rendering the model data and in general it generates HTML output that the client's browser can interpret.
• The Controller is responsible for processing user requests and building appropriate model and passes it to the view for rendering.

Spring provides a front controller servlet named DispatcherServlet. To build an application, you construct the following components:

• One or more controllers that invoke business logic and create a ModelAndView object
• A visualization component such as a JSP
• XML or annotation configuration to wire the components together

Spring provides various controllers for you to use as base classes for creating your own controllers, depending on your needs. Among them are ones that:

• Redirect to static views
• Provide basic servlet-like functionality
• Process commands
• Process shared actions
• Handle forms
• Provide wizard-like functionality to process multipage forms

If you really want to learn and implement Spring MVC in your Java projects, I recommend you to have you Eclipse IDE ready and watch "Spring MVC Tutorial for Beginners" YouTube video. That tutorial will guide you step by step in a very easy and detailed way. So far, one of the best tutorials.