🔒 Cyber Threats Series, Part 4: Cross-Site Scripting (XSS) & Cross-Site Request Forgery (CSRF)

Welcome to Part 4 of the Cyber Threats Series, where we’ll explore two critical web vulnerabilities: Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF). Don’t worry, we’ll break it down to make it super easy to understand! 😊

What Is XSS (Cross-Site Scripting)? 🤔

XSS happens when a web application doesn’t properly sanitize user input and sends it back to the user. Attackers exploit this to inject malicious code (usually JavaScript), which can:

Steal information like cookies or session tokens. 🕵️‍♂️
Redirect users to malicious websites. 🌐
Control the victim’s browser to perform actions. 🚨

Types of XSS Attacks

1. Stored XSS 🗄️

Stored XSS occurs when the malicious script is saved on the web server, often in a database. It executes whenever users view the compromised data.

Example: Posting a malicious comment like:

<script>alert('Hacked!');</script>

This script runs whenever someone views the comment.

2. Reflected XSS 🔄

Reflected XSS involves injecting malicious code into a URL or form field. The script is "reflected" back in the server's response and executed in the user's browser.

Example: A crafted URL like:

https://example.com/search?query=<script>alert('Hacked!');</script>

3. DOM-Based XSS 🖥️

In DOM-based XSS, the attack occurs entirely on the client side. The server doesn’t directly include the malicious input in its response, but client-side scripts process and execute it.

How to Prevent XSS 🛡️

Sanitize inputs: Remove or encode dangerous characters.
Use libraries: Tools like DOMPurify clean inputs automatically.
Content Security Policy (CSP): Restrict the execution of unauthorized scripts.

What Is CSRF (Cross-Site Request Forgery)? 🤔

CSRF tricks authenticated users into performing actions they didn’t intend by exploiting their active session.

How Does CSRF Work?

1️⃣ A user logs into their account.
2️⃣ The attacker sends a malicious link.
3️⃣ The user's browser unknowingly performs actions using their session token.

How to Prevent CSRF 🛡️

CSRF Tokens: Use unique, dynamically generated tokens for each request.
Re-authentication: Ask users to re-enter their password for critical actions.
Validate Referrer Headers: Ensure requests come from trusted sources.

Quiz Time! 🎉

Q1: What type of XSS attack stores malicious code on a server?

A) DOM-Based XSS
B) Reflected XSS
C) Stored XSS

Answer: C) Stored XSS

Q2: What is an effective way to prevent CSRF?

A) Use JavaScript libraries.
B) Validate session cookies.
C) Use a CSRF token.

Answer: C) Use a CSRF token

Key Takeaways 📝

1️⃣ XSS allows attackers to run malicious scripts in users’ browsers. Prevent it with sanitization and CSP.
2️⃣ CSRF tricks users into performing unintended actions. Prevent it with CSRF tokens and session validation.

Stay tuned for the next part of the Cyber Threats Series! 🚀