Thanks to the Netscape engineers who introduced the Same-Origin Policy (SOP), you can freely browse sensitive web pages without sharing your data with another page.
Even as important as it is, the same-origin policy concept is difficult to comprehend by many internet users. This article will give you a better understanding of how it works and why it's important.
What Is the Same-Origin Policy (SOP)?
The same-origin policy is a browser security mechanism whereby a web browser restricts another webpage script and data from accessing their data and information. However, it permits the web page's scripts and data that correlate with it.
In the same-origin policy, browsers prevent contents of different origins (webpages) from interfering with theirs. The rules of the same-origin policy state that all resources loaded by a browser must have the same protocol (can also be referred to as scheme), URL, and port used to reach the resource.
Here's an example:
Let's say you visit the webpage myexample.com and then visit example.com afterward. The same-origin policy is what prevents the JavaScript of myexample.com from accessing the information on example.com.
The protocol is the "http," the domain is the "myexample.com" or "example.com," and the port number "80." By default, every website or web page tends to have the same port, which is "80."
Without the same-origin policy, after logging into myexample.com, a simple JavaScript call, loaded in its iframe, could be used to enter the DOM (Document Object Model) elements of example.com. This will lead to sensitive data exposure with damaging consequences.
It's important to note that the same-origin policy only pertains to scripts. Resources such as CSS, images, and flexible loaded scripts can be made available from different origins using the appropriate HTML tags with fonts being a notable exception.
Therefore, any attacks made on the non-scripts are effective because attackers exploit the fact that HTML tags are not subject to the same-origin policy. This is undoubtedly one of its shortcomings.
Another shortcoming is the recurrent limits placed on the number of complex operations in modern web applications.
Even though the same-origin policy is remarkable for security, most times, it affects multiple subdomains or domains of the same organization. Sharing information with the domains is difficult even though they are together.
Why Is the Same-Origin Policy (SOP) Important?
The same-origin policy is not merely about creating rules between web pages or origin; it's relevant, especially regarding cyberattacks. It offers some security benefits to online users in securing their information.
Here are some benefits of the same-origin policy.
1. Prevents Malicious Attacks
The same-origin policy helps eradicate potentially malicious attack vectors on a webpage or origin, especially on webpages that house or store sensitive user data. It does this by waging perceived potential attacks spot on before they escalate.
If you implement the same-origin policy on your webpage or browser, there's a significant decrease in malicious attacks.
2. Restriction of Interaction
The same-origin policy helps restrict how a script from a website interacts with a script of another webpage.
When there's a restriction in the shared data, all resources from an origin are highly protected. A vivid example of this is the one we mentioned about myexample.com scoping the script of example.com.
3. Prevent Unauthorized Read Access
The same-origin policy helps in protecting sites that use authentication sessions. This can be seen in sites that use the "remember me" functionality.
The policy works by keeping privileged information safe. It prevents unauthorized read access from one origin to another.
4. Effective for Cookies
The same-origin policy prohibits an attacker from reading or establishing cookies on the targeted source domain. It prevents them from inserting a valid token into their devised form. The permit doesn't need to be stashed on the server, which is an added benefit of this technique over the timing pattern.
Secure Your Data With the Same-Origin Policy
The same-origin policy is a construct at the heart of many web security processes, including DOM access, JavaScript, cookies, and more.
There are various implementations of the same-origin policy for different types of web content. Similarly, there are different definitions for how the same-origin policy applies to cookies, JavaScript, and DOM access across browsers.
Exercise more caution when establishing your site to provide better security and enhance the user experience with the same-origin policy.