1. How Card Data Is Typically Stored
Card data (PAN, CVV, expiration dates, cardholder names) is stored in databases protected by layers of security. Common storage formats include:
- SQL Databases: MySQL, PostgreSQL, MSSQL (often used in payment gateways).
- Encrypted Storage: Modern systems encrypt card data using AES-256 or tokenization.
Example of a Secure SQL Schema:
SQL:
CREATE TABLE customers (
id INT PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(100),
email VARCHAR(100) UNIQUE,
card_hash VARCHAR(255) -- Hashed/stored securely (e.g., using bcrypt)
);
2. Common Vulnerabilities (For Educational Purposes)
If you’re studying
how attackers exploit systems, here are examples of vulnerabilities (for defensive learning only):
A. SQL Injection (SQLi)
Attackers inject malicious SQL queries to extract data from databases.
Example (Educational Lab Only):
SQL:
-- Vulnerable query (do NOT use in real systems)
SELECT * FROM users WHERE username = '$username' AND password = '$password';
-- Exploit payload
$username = "admin' --";
$password = "anything";
This bypasses authentication and dumps data.
Tools for Learning:
- SQLMap: An open-source tool to detect SQLi vulnerabilities (used in penetration testing).
- DVWA (Damn Vulnerable Web App): A practice platform for learning SQLi and other attacks.
B. Credential Stuffing
Using leaked credentials (e.g., from breaches) to access systems.
Defensive Countermeasure: Multi-factor authentication (MFA), rate limiting, and monitoring.
C. Phishing
Tricking users into revealing card details via fake websites or emails.
Example: Clone a bank’s login page to harvest credentials.
3. Legal and Ethical Alternatives to Learn
To study card data security without breaking laws:
A. Use Authorized Training Platforms
- Hack The Box (hackthebox.com): Practice SQLi, web exploitation, and network security in a legal sandbox.
- TryHackMe (tryhackme.com): Offers guided labs on SQL injection and PCI DSS compliance.
- OWASP Juice Shop: A vulnerable web app for learning secure coding.
B. Learn SQL and Database Security
- SQLZoo (sqlzoo.net): Interactive SQL tutorials.
- Coursera: Courses like "SQL for Data Science" or "Cybersecurity Fundamentals."
- Books: "The Web Application Hacker’s Handbook" (focus on defensive strategies).
C. Bug Bounty Programs
Participate in programs like:
- HackerOne (paypal.com, x.com, etc.).
- Intigriti (European-focused).
- YesWeHack (global platform).
4. Tools for Defensive Learning
- SQLMap: Detect SQLi vulnerabilities in your own systems (with permission).
- Burp Suite: Analyze web traffic and test for vulnerabilities.
- Nmap/ZAP: Scan networks and applications for weak points.
5. Real-World Example (Educational Lab)
Scenario: A vulnerable e-commerce site allows SQLi via the login form.
Steps:
- Use DVWA to simulate the attack.
- Input ' OR '1'='1 into the username field to bypass authentication.
- Use SQLMap to dump the database:
Bash:
sqlmap -u "http://dvwa/login.php" --POST "username=admin&password=admin" --dbs
- Analyze results (e.g., extract card hashes).
Note: This is
only for educational purposes in controlled environments.
6. Protecting Against Card Data Theft
If you’re a developer or security professional, focus on:
- Encrypting card data at rest (AES-256).
- Tokenization: Replace card numbers with tokens (e.g., Stripe, Braintree).
- PCI DSS Compliance: Follow standards like PA-DSS for payment apps.
- Input Validation: Sanitize user inputs to prevent SQLi.
Classic "carding" is dead due to EMV + AI fraud detection.
