XSS in Markdown

👉 Overview

👀 What ?

Cross-Site Scripting, commonly known as XSS, is a type of security vulnerability typically found in web applications. XSS enables attackers to inject malicious scripts into web pages viewed by other users. A breach of this nature can lead to a range of issues, including identity theft, data theft, and other malicious activities.

🧐 Why ?

Understanding XSS is crucial due to its prevalence and potential harm. XSS vulnerabilities can exist in any web application that uses input from a user within the output it generates without validating or encoding it. An attacker can use XSS to send a malicious script to an unsuspecting user, leading to potential data theft or malicious control of their interactions.

⛏️ How ?

To leverage XSS, an attacker needs to find a way to inject malicious code into a web page that the target user visits. They can do this by finding a vulnerability in a web application that the user interacts with. For example, an attacker could post a link or a script on a forum that contains the malicious code. When the user clicks on the link or the script, the code is executed, and the attacker can gain control.

⏳ When ?

XSS attacks have been around since the early days of the internet. They became increasingly prevalent with the rise of web applications in the late 1990s and early 2000s. Despite advancements in web security, XSS remains a common threat due to the complexity of detecting and preventing all potential instances.

⚙️ Technical Explanations

XSS attacks occur in two primary types: Stored and Reflected. Stored XSS attacks involve an attacker injecting a script that is permanently stored on the target server, such as via a comment field, and is served to users within the web application. Reflected XSS attacks involve the script being included as part of a URL query, which is then processed by the server and sent back to the user. The attack occurs when the user's browser executes the script returned in the server's response. Protection against XSS typically involves the use of web application firewalls, input validation, and output encoding.