Many people may wonder why this would be an issue. Sure, there are legitimate reasons for loading website content in an iFrame. You might be using iFrames within your website to show portions of content that are updated through another tool or service, or you may be showing content from an external website that isn’t available through an API. All of this is fine and good, assuming it is above board. You may also want your website to be loaded in iFrames on external sites for similar reasons. While this is still a viable and safe method, there are a number of less ethical ways hackers and content thieves use iFrames that you should watch out for.
Common ways iFrames are exploited
Clickjacking or UI redress attack – a popular way of tricking a user to click on a button or link that is overlaid on top of your website. The user thinks they’re clicking on your website or button, but instead, they’re clicking on a transparent or camouflaged button that takes them to the attacker’s site. This will cause your customers to think they’re on your website when they’re in fact providing their information to the attacker.
Unauthorized content republishing – Other website owners may use iFrames to portion out some of your unique content to display on their website instead of getting permission to use this content, or directing their users to your website.
Common ways iFrames are exploited
Yuck, that doesn’t sound fun at all. So how do you prevent other websites or attackers from loading your website in an iFrame? There are two primary methods:
1.) Sending an X-Frame-Options HTTP response header that instructs the browser to disable framing from other domains.
An example of using PHP to send the X-Frame-Options header.
<?PHP
header('X-Frame-Options: SAMEORIGIN');
?>
An example of using .htaccess to send the X-Frame-Options header.
Header set X-Frame-Options SAMEORIGIN
2.) Employ defensive code that will analyze how your website is loaded to confirm it is the top level window, and redirect the user if this is not the case.
<style id="antiClickjack">body{display:none !important;}</style><br><script type="text/javascript" if (self === top) { var antiClickjack = document.getElementById("antiClickjack"); antiClickjack.parentNode.removeChild(antiClickjack); } else { top.location = self.location; } </script>
Original concept: http://seclab.stanford.edu/websec/framebusting/framebust.pdf
It is safe to use a combination of these strategies and currently, in my opinion, the best method. Some older browsers do not support the X-Frame-Options header. To my knowledge, all browsers support the Javascript code in option 2 if Javascript is enabled. Using a combination would capture nearly all website users and options, helping to greatly secure your website against content thieves and clickjacking attacks.
