Implications of a JS Injection Attack
- comment fields
- any other form with user-editable text box
JS injection typically changes the website's appearance and is able to let the attacker change certain parameters. The consequences range from information leak to damaged website designs, which can be done with the aid of social engineering tricks.
Checking for JS injection
The testing of JS injection is very important, and the vulnerability test should be incorporated as a standard test in an organization’s security testing routines.
- An 'Executed!' pop-up on the screen shows that the website is vulnerable to JS injection attack.
- Use regex on user's input. There are different libraries and each uses a varying and customized regex.
Using regex, though, can be complex, depending on the complexity of the regex string in the library used. Knowing the part of the website injected with a JS attack is the precursor to figuring out the best way to check for such attacks.
Prevention and Protection from JS Injection Attacks
The first step to protection is the prevention of the attack, and this starts with validating every received input before submission. Input details should be validated at all times and not only at the point of data entry. Security protocols should be installed and website owners or managers must not only rely on the client-side validation, but also on a logic analysis on the server-side.
1. HTML Encode in the View
HTML encoding is one of the most popular JS injection mitigation techniques. In this approach, the data entered by website users, during display are encrypted with the use of special characters. By encoding a feedback.message with HTML, the value that will be shown in the view is:
To HTML encode, a string of characters including, < and > are replaced with different entities such as < and >. Therefore, in a typical string like <script>alert("Confirm!")</script> becomes <script>alert("Confirm!")</script> . This language is then interpreted by the browser, to show a harmless message, <script>alert("Confirm!")</script> , instead of a Pop-up alert.
2. HTML Encode in Controller
Instead of HTML encoding data when displayed, the data can be alternatively encoded before it is submitted to the database. This is done in the controller case controller.cs.
To do this right, the message value must be HTML-encoded before the value is submitted to the database within the create ( ). With this method, however, you will have HTML-encoded data in your database.
3. Using Vulnerability Test Tools
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