Recently, we consulted on a breach involving a major ecommerce website where attackers compromised the checkout process to steal customers’ payment card data. This attack exploited vulnerabilities in how the site managed payment pages, highlighting critical lessons for all ecommerce operators.
The attackers injected malicious JavaScript into the application, targeting an onclick action when users clicked “continue” during checkout. Although the platform relied on a secure API to process payments, it temporarily stored card data in memory—creating an exploitable vulnerability. This, combined with a misconfigured system that allowed third-party scripts to load, led to a severe online skimming attack.
The root causes of the breach were:
- Self-hosting payment pages instead of using a secure, hosted solution.
- Allowing the side-loading of third-party scripts due to inadequate content security measures.
This costly mistake underscores the importance of proper configurations. In this article, we’ll break down these issues and provide actionable steps to protect your ecommerce environment.
Hosted vs. Self-Hosted Payment Pages: The Safer Choice
Self-Hosted Payment Pages:
In a self-hosted setup, the website owner collects or processes payment card information, even if only temporarily. While this approach provides more control, it significantly increases security risks and compliance burdens. Any vulnerability in the system can expose customer data to attackers.
Hosted Payment Pages:
A hosted payment page delegates the entire payment process to a trusted third-party provider (e.g., PayPal, Stripe, Recurly). This method shifts the responsibility and liability of handling sensitive cardholder data to the payment gateway, offering superior security and compliance benefits.
Best Practice:
For modern ecommerce websites, using a hosted payment page is the industry standard. It minimizes the risk of breaches and simplifies compliance with PCI DSS requirements. Platforms like Shopify already enforce this model, but if you self-host on platforms like WordPress or Magento, adopting a hosted solution is critical to safeguarding your business and customers.
Strengthen Security with Content Security Policy (CSP) Headers
Another critical vulnerability in the above case was the ability to load malicious third-party scripts. This attack vector could have been mitigated with properly configured security headers, particularly a Content Security Policy (CSP).
What Are Security Headers?
Security headers are HTTP response headers that instruct web browsers on secure behaviors, such as preventing unauthorized script execution or restricting resource loading to trusted domains.
Content Security Policy (CSP):
CSP headers allow you to specify which domains are authorized to execute scripts on your site. By implementing CSP, you can block unauthorized scripts, such as those injected by attackers. In this case, a properly configured CSP would have prevented the malicious JavaScript payload from being executed.
Key Takeaways for Ecommerce Security
- Adopt Hosted Payment Pages:
Delegate payment processing to trusted gateways like PayPal or Stripe to minimize compliance challenges and reduce risk. - Implement Strong Security Headers:
Use headers like CSP to block unauthorized scripts and protect your application from cross-site scripting (XSS) and other injection-based attacks. - Comply with PCI DSS Standards:
Hosted payment pages simplify compliance by shifting responsibility to the payment processor, ensuring your business remains secure and compliant.
The Modern Web Mandates Hosted Payment Pages and Forms
The modern web demands robust security measures for ecommerce transactions. By leveraging hosted payment pages and configuring critical security headers like CSP, you can drastically reduce your exposure to attacks, protect customer data, and maintain trust.
When in doubt, partner with industry-standard payment gateways and invest in security best practices—because the cost of negligence far outweighs the investment in prevention.