"Clickjacking is a malicious technique of tricking web users into revealing confidential information or taking control of their computer while clicking on seemingly innocuous web pages." - Wikipedia
Introduction :-
A vulnerability across a variety of browsers and platforms, a clickjacking takes the form of embedded code or script that can execute without the user's knowledge, such as clicking on a button that appears to perform another function.
The long list of vulnerabilities involves browsers, Web sites and plug-ins like Flash.
How It Works? :-
ClickJacking is a little bit difficult to explain however try to imagine any button that you see in your browser from the Wire Transfer Button on your Bank, Post Blog button on your blog, Add user button on your web-site, Google Gadgets etc.
ClickJacking gives the attacker to ability to invisibly float these buttons on-top of other innocent looking objects in your browser.
So when you try to click on the innocent object, you are actually clicking on the malicious button that is floating on top invisibly.
In other words, the attack is thrown by a malicious web page embedding objects, possibly from a different site, such as framed documents or plugin content (Flash, Silverlight, Java…) which may lead to unwanted results if clicked by the current user (e.g. a “Delete all messages” button in your webmail or an advertisement banner in a click fraud scheme). Using DHTML, and especially CSS, the attacker can disguise or hide the click target in several ways which go completely undetected by the user, who’s easily tricked into clicking it in a more or less blind way.
JavaScript increases the effectiveness of these attacks hugely, because it can make our invisible target constantly follow the mouse pointer, intercepting user’s first click with no failure.
We can however imagine a few less effective but still feasible scriptless scenarios, e.g. covering the whole window with hidden duplicates of the target or overlaying an attractive element of the page, likely to be clicked (e.g. a game or a porn image link), with a transparent target instance.
Examples :-
1) Malicious camera spying using Adobe's Flash.
2) Flash, Java, SilverLight, DHTML Game or Application used to Spy on your Webcam and/or Microphone.
 | The best defense against ClickJacking attacks is to use Firefox with the NoScript add-on installed. |
NoScript 1.8.9.2Allow active content to run only from sites you trust,
and protect yourself against XSS and Clickjacking attacks...!
