Cross-Site Request Forgery (CSRF) is a cyberattack that exploits the trust a web application has in a user’s browser. Also known as a “one-click attack” or “session riding,” CSRF tricks authenticated users into performing unintended actions on a web application without their knowledge or consent. These attacks can lead to unauthorized data changes, account modifications, or other malicious activities.
How CSRF Works
1. Authentication Dependency:
CSRF relies on the victim being logged into a web application.
2. Malicious Request Creation:
Attackers craft a malicious request that appears legitimate to the web application.
3. Trick the Victim:
The victim is lured into executing the malicious request, often via a link or embedded script in an email, chat, or third-party website.
4. Server Trust:
Since the victim is authenticated, the server processes the request assuming it is legitimate.
Common Scenarios
Banking Transactions:
Transferring funds to the attacker’s account using the victim’s session.
Account Hijacking:
Changing the victim’s email or password in an application.
Posting Malicious Content:
Publishing spam or harmful links on the victim’s social media accounts.
Mitigation Techniques
1. CSRF Tokens:
Include unique, unpredictable tokens in web forms and validate them on the server side.
2. SameSite Cookies:
Configure cookies with the SameSite attribute to restrict cross-origin requests.
3. Double Submit Cookies:
Validate a CSRF token sent both as a cookie and a hidden form field.
4. User Authentication:
Require re-authentication for sensitive actions.
5. Check Referrer Header:
Verify that requests originate from authorized domains.
Code Example: CSRF Token Implementation in Flask
from flask import Flask, request, render_template_string
app = Flask(__name__)
CSRF_TOKEN = “secure_random_token”
@app.route(‘/form’, methods=[‘GET’, ‘POST’])
def form():
if request.method == ‘POST’:
token = request.form.get(‘csrf_token’)
if token != CSRF_TOKEN:
return “CSRF Detected!”, 403
return “Form submitted successfully!”
return render_template_string(”’
<form method=”post”>
<input type=”hidden” name=”csrf_token” value=”{{ csrf_token }}”>
<input type=”text” name=”data”>
<button type=”submit”>Submit</button>
</form>
”’, csrf_token=CSRF_TOKEN)
if __name__ == “__main__”:
app.run(debug=True)
Schematic Representation
Victim Logs In -> Attacker Crafts Request -> Victim Executes Request (Unaware) -> Server Processes Request
Conclusion
CSRF attacks exploit the implicit trust between a user’s browser and a web application. To mitigate these risks, developers must implement security measures like CSRF tokens, SameSite cookies, and origin verification. By understanding and addressing these vulnerabilities, businesses can protect their systems and user data from unauthorized manipulation.
The article above is rendered by integrating outputs of 1 HUMAN AGENT & 3 AI AGENTS, an amalgamation of HGI and AI to serve technology education globally.