Credit Card Data Security: A Bank’s Guide

TL;DR

Banks should never store credit card data in plain text. This is a massive security risk. We’ll cover how to identify the problem, secure existing data, and prevent future occurrences using encryption, tokenization, and strong access controls.

1. Identifying Plain Text Storage

1. Database Audits: Regularly scan your databases for unencrypted credit card numbers (PANs), CVV codes, expiry dates, and names. Use database-specific tools or security scanning software.
2. Log Analysis: Review application logs for instances where credit card data might be logged in plain text.
3. Code Reviews: Examine your applications’ source code to identify any places where credit card data is handled without encryption. Look for direct storage into files or databases without proper protection.
4. Network Sniffing (Carefully!): In a controlled environment, use network sniffing tools to check if credit card data is transmitted in plain text over your internal networks. Warning: This should only be done by experienced security professionals and with appropriate permissions.

2. Securing Existing Data

1. Encryption at Rest: Encrypt all existing credit card data stored in databases or files. Use strong encryption algorithms like AES-256. Most database systems offer built-in encryption features.

   -- Example (PostgreSQL):

   ALTER TABLE customers ALTER COLUMN credit_card_number TYPE VARCHAR(255) ENCRYPTED;

2. Tokenization: Replace sensitive credit card data with non-sensitive tokens. A tokenization service handles the actual storage and encryption of the real card details.
   • Consider using a PCI DSS compliant tokenization provider.
   • Tokens should be unique and irreversible to prevent reverse engineering.
3. Data Masking: If full decryption isn’t necessary, mask the credit card data (e.g., show only the last four digits).

3. Preventing Future Storage of Plain Text Data

1. Encryption in Transit: Ensure all communication channels used to transmit credit card data are encrypted using TLS/SSL.
   • Use strong cipher suites and keep your SSL certificates up-to-date.
2. Secure Coding Practices: Implement secure coding practices that prevent the storage of sensitive data in plain text.
   • Never hardcode credit card numbers into applications.
   • Use appropriate libraries and frameworks for handling payment information securely.
3. PCI DSS Compliance: Adhere to the Payment Card Industry Data Security Standard (PCI DSS). This standard provides a comprehensive set of security requirements for handling credit card data.
   • Regularly assess your compliance with PCI DSS.
   • Implement strong access controls and monitoring systems.
4. Access Control: Limit access to credit card data to only authorized personnel.

   -- Example (Linux):

   chmod 700 /path/to/sensitive/data; chown root:root /path/to/sensitive/data;

5. Regular Security Audits & Penetration Testing: Conduct regular security audits and penetration testing to identify vulnerabilities in your systems.
   • Engage a qualified security firm for these assessments.

4. Incident Response Plan

1. Develop a plan: Create an incident response plan to address potential data breaches.
   • Include steps for containment, eradication, recovery, and notification.
2. Regular testing: Test your incident response plan regularly to ensure its effectiveness.