Web Application Firewalls (WAF) Explained

What a WAF Actually Does

A web application firewall, commonly called a WAF, inspects incoming traffic to your website or application, filtering out malicious requests before they reach your actual code. Unlike a traditional network firewall, which primarily controls access based on ports and protocols, a WAF specifically understands web application traffic and can identify attack patterns within that traffic itself.

If you have not yet read [INTERNAL LINK: "Understanding DDoS Protection and Mitigation", link to this article using its slug understanding-ddos-protection], it covers a related but distinct type of protection focused on traffic volume rather than malicious request content.

Types of Attacks a WAF Helps Prevent

SQL injection attempts, where an attacker tries to manipulate a database query through malicious input in a form field, are commonly filtered by a properly configured WAF. Cross site scripting attempts, where malicious code is injected into a page viewed by other users, are similarly identified and blocked. A WAF can also filter known bad bot traffic and other automated attack patterns before they reach your application.

How a WAF Differs From Application Level Security

A WAF operates as a protective layer positioned in front of your application, catching many attack attempts before they ever reach your actual code. This does not replace the need for secure coding practices and keeping your application's own software updated, but it adds a meaningful additional layer of defense, particularly valuable for catching attacks against known vulnerability patterns even before an application specific patch is available.

Rule Based Filtering

WAFs typically operate using a set of rules defining what patterns of traffic are considered suspicious or malicious. These rule sets are regularly updated to account for newly discovered attack techniques, meaning a WAF's protection improves over time without requiring manual configuration changes on your part for most standard threats.

False Positives and Fine Tuning

Occasionally, a WAF's rules may flag legitimate traffic as suspicious, particularly for applications with unusual input patterns that resemble attack signatures without actually being malicious. If you notice legitimate functionality being blocked, this can typically be addressed by fine tuning specific rules for your application, worth raising with our support team if you encounter this.

Is a WAF Included With Your Hosting

WAF protection is often included as part of broader security infrastructure, with the specific level of protection and customization available varying by hosting tier. If your application handles particularly sensitive data or has previously been targeted by attacks, it is worth discussing enhanced WAF configuration specifically suited to your application with our team.

WAF Protection Is Not a Complete Solution

While a WAF meaningfully reduces your exposure to common attack patterns, it works best as one layer within a broader security approach, alongside keeping your own software updated and following secure practices in how your application itself is built and maintained.