Companies that connect to and conduct business online—essentially all businesses at this point—understand the need for web security. A content delivery network (CDN)-based web application firewall (WAF) provides the easiest way to set up basic web application protection. It makes perfect sense, especially for small companies. Larger companies and enterprises are less willing to share the traffic of its customers with a third-party provider even if the provider is trusted. But recent news on the reliability of WAF vendors has raised red flags for security professionals on whether to depend on fully cloud-based WAF solutions at all.
The front-end activity—the CDN/WAF interface, which is a single point of access for all incoming unencrypted data—is all centralized. The security of this centralized server is the weakest link in the web application and API security of all its clients. When the main entrance is redirected to the provider, that becomes a front door for the hackers.
The cloud-based security services that are meant to protect websites from vulnerabilities by filtering the incoming traffic are themselves vulnerable to client-side vulnerabilities, such as cross-site request forgery (CSRF) or cross-site scripting (XSS) attacks. They’re also susceptible to access takeover attacks (credentials being hacked) and vulnerabilities that arise during any online transaction.
Exploiting these vulnerabilities, hackers can exfiltrate valuable customer data such as customer SSL certificates, as just one example. Exposure is further amplified by the difficulty of protecting APIs with regular-expression-based solutions. Legacy WAFs lack the ability to properly parse complicated API formats such as REST/JSON/SOAP/XML.
The latest example of a cloud-based service being hacked is the breach reported by Imperva Incapsula this week. As the company has disclosed, the following data were exposed:
- Email addresses
- Hashed and salted passwords
- API keys
- Customer-provided SSL certificates
SSL certificates disclosure is especially worrisome. Exposure of SSL keys would allow attackers full access to unencrypted data of service customers and would further enable a number of attacks, including man-in-the-middle.
Better Web Security
By contrast to CDN-based WAF, cloud-native deployment as a reverse proxy (Docker, Kubernetes or just from Linux packages) preserves data privacy and keeps sensitive data within the customer infrastructure. With the hybrid solutions, initial processing and detection are performed by filtering nodes that work as part of local load balancing infrastructure.
Neither SSL certificates nor API keys need to be shared outside of the client organization. Data exposure and threat vectors are limited, which reduces the compliance perimeter and the potential risk of data exposure.
Minimizing the overall attack surface and eliminating single points of failure are both solid best practices for cybersecurity in general—and web security specifically. If you don’t want to put your web traffic at risk, it makes sense to explore alternatives to CDN-based WAF solutions.