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1. #Other side incorrect authentication express talk how to#
2. #Other side incorrect authentication express talk movie#
3. #Other side incorrect authentication express talk install#
4. #Other side incorrect authentication express talk code#
5. #Other side incorrect authentication express talk download#

#Other side incorrect authentication express talk code#

In this case, the placeholder highlighted in the code snippet above is replaced with the reviews sent by the user without any validity check. Data is accepted as it is sent, without any control over its validity and security. Here, the main reason for the XSS vulnerability lies in the lack of sanitization of the data sent by the user.

#Other side incorrect authentication express talk movie#

The relevant part of the HTML template for the movie page looks as follows: Submit Comments It sends the result to the user's browser in the HTTP response.It replaces the $reviews$ placeholder with the formatted string.It creates a formatted string obtained by joining the reviews array.It adds the new review to the reviews array.Basically, when the server receives the request, it performs the following steps: In the code above, it is represented by the app. Let's focus on the relevant point of this investigation: how the server handles the website page's request. Now, assume you are the attacker visiting the streaming website and, instead of adding a review to the movie, you add the following string in the review text box: fetch ( ` $ ` ) ) This website is meant to capture private data from the vulnerable website by exploiting its cross-site scripting vulnerabilities. To ensure that it runs correctly, point a new tab of your browser to the address. Now that the vulnerable website is up and running, launch the attacker's website typing this command: node attacker-server.js When you add your review, you see it appearing in the comments section. For simplicity, assume that users have already been authenticated, and this is just one specific step in the user's journey on the website. Users can add their review to the movie by simply filling in the text box and clicking the submit button. The project implements a specific movie page of a fictitious movie streaming website.

#Other side incorrect authentication express talk install#

Now, move into the project's root folder and install the project's dependencies by running the following command: npm installįinally, launch the vulnerable website by running this command: npm start

#Other side incorrect authentication express talk download#

So, to get the playground environment where to experience firsthand an XSS attack, download the sample project from GitHub by running this command in a terminal window: git clone In addition, since XSS attacks involve JavaScript, your client-side code is affected too.

The principles you will learn can be applied to any technology like ASP.NET, PHP, Django, and so on. To set up this environment, you just need Node.js installed on your machine.Īlthough the example shown in this article uses Node.js as a server runtime, be aware that XSS attacks are not related to a specific server-side technology. To better understand how XSS attacks work, you are going to set up an environment with all the elements to reproduce a simplified version of such type of attacks. These possibilities may be very harmful to your website or web application, as you will learn in this article. Also, JavaScript can send data to arbitrary servers and manipulate the DOM of the current page. However, JavaScript can access many sensitive data related to the website the user is browsing, like, for example, cookies, security tokens, and other similar data. After all, JavaScript has no direct access to the user's system. In fact, the snippet of JavaScript code injected into the vulnerable website will run on the victim's web browser.Īt first glance, this may seem not so critical. The attacker: a user who injects the malicious code, typically in JavaScript, into the vulnerable website.īasically, the attacker uses the vulnerable website as a means to deliver their malicious script to the actual victim: the user of the vulnerable website.The victim: a user of the vulnerable website, the actual target of the attack.

#Other side incorrect authentication express talk how to#

In this article, you'll learn what an XSS attack is and how to defend against it by inspecting an application that is vulnerable to an XSS attack and then updating the code to fix the vulnerability.īeing aware of these types of vulnerabilities in your application and knowing how to prevent attacks is a must for any Web developer. Of course, if you don't know how it works, you cannot defend against it. Although it's a well-known type of attack, not all developers are really aware of how it works. Cross-Site Scripting is one of the most common attacks based on code injection.