XSS is a type of Cross-site Request Forgery (CSRF) that attackers use to steal personal data from a user’s session. All you need to do to get exploited is click on a malicious link sent via email. A website’s code can be injected with malicious script that can then be sent to other visitors of the website via email. These visitors don’t need to do anything special to be compromised. The malicious code just needs to be sent to a user via email.
How to protect against XSS? - To protect your website against XSS, you must validate the input of your users. In other words, your users must be given a chance to correct any possible data entry errors. Otherwise, the malicious script sent via email could be executed against an unsuspecting user. -
Inline HTML Validation
One simple way to prevent XSS attacks is by making sure that your website’s HTML code has inline HTML validation. An example of this would be if you have a text input field and the user has to submit his or her name, then the developer should validate the input before it goes into an output field on the site. By doing so, if an error is made in the text field and not corrected, then the error will be caught before it is displayed on the site. One thing that makes inline HTML validation difficult for developers is that sometimes developers are not always able to determine what type of content a user enters. This means that finding validation criteria for each input field can be tough. However, by using regular expressions, a developer can make sure that any possible data entry errors are caught. One example of how this could work would be if you wanted to check for an email address in an input field. You could use a regular expression like "^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-z]{2}$" which would make sure that only email addresses with valid characters are accepted in your input fields.
How to prevent XSS with HTML Purifier?
To prevent XSS, you can use HTML Purifier. This is because HTML Purifier has a whitelist mode that prevents bad input from executing and a blacklist mode that blocks possible malicious scripts from being executed. If you are using WordPress, you can use the Blacklist Mode plugin to block malicious scripts from running on your website.
HTML Purifier is an open source tool that helps prevent Cross-site Scripting (XSS) attacks by validating data entered by users. It uses heuristic scanning techniques to determine whether or not a script is malicious and stops it before it executes.
You can also run scans when you upload a new site with the Blacklist Mode plugin for WordPress, which will help ensure your site stays XSS free.
How to detect XSS?
Sometimes, it's hard to detect an XSS vulnerability before it gets exploited. However, there are some techniques that can help you detect XSS.
- Most importantly, use a sanitization filter on all user inputs and outputs to prevent cross-site scripting attacks. - Use a web debugger such as Neamzter or Firebug to simulate requests and look for unexpected results. - Check for unusual database queries in the site's logs. For example, if the site is vulnerable to SQL Injection, a database query could be executed against your website's database without your knowledge.
Input validation in HTML
The input being sent to HTML must be validated. There are two ways of doing this. One way is to use the JavaScript document.cookie object's setItem method and the second is to validate against a server-side script or database. For example, you can use the following code:
if (document.cookie.length >= 8) {
return true;
} else { return false; }
What is XSS?
Cross-site scripting is a type of security vulnerability that allows malicious script to be executed on a website. The malicious scripts are usually injected into the website's code by an attacker and executed in the context of the victim's browser. XSS attacks take advantage of three major web application vulnerabilities: - The ability to dynamically create new HTML pages without user interaction - The ability to store cookies that are not domain specific and can be read from any domain - The child object access vulnerability within HTML documents (HTML5)
How will you know if you have xss? - You'll know that you have XSS if your site has an error suggesting it may have been compromised
Timeline
Published on: 02/06/2022 11:15:00 UTC
Last modified on: 02/11/2022 03:15:00 UTC