Server Side XSS (Dynamic PDF)

👉 Overview

👀 What ?

Server Side XSS (Cross-Site Scripting) in dynamic PDF generation is a type of vulnerability where an attacker can inject malicious scripts into a PDF file generated on the server side. These scripts are then executed when the user opens the PDF file.

🧐 Why ?

Understanding Server Side XSS, particularly in dynamic PDF generation, is important because it can lead to significant security breaches. Attackers can use this vulnerability to steal sensitive information, manipulate web content, and carry out other malicious activities. Therefore, any system that generates PDF files on the server side is at potential risk.

⛏️ How ?

To exploit this vulnerability, an attacker generally injects malicious scripts into inputs that are included in the PDF file. These scripts are not properly escaped or sanitized by the server when the PDF is generated. When the user opens the PDF file, the scripts are executed, giving the attacker the ability to carry out malicious activities.

⏳ When ?

Server Side XSS attacks became more prevalent with the rise of web applications that dynamically generate PDF documents on the server side. This trend started around the mid-2000s and continues to be a security concern today.

⚙️ Technical Explanations

Server Side XSS in dynamic PDF generation occurs when a server-side script generates a PDF file without properly sanitizing user-supplied input. This leads to the possibility of an attacker injecting malicious scripts into the PDF file. When the user opens the PDF, the script is executed within their browser context, potentially leading to data theft or other malicious actions. The fundamental concept here is the lack of input sanitization and output encoding, which are crucial in preventing XSS attacks.