Web Application Firewall (WAF) is a security solution that monitors, filters, and blocks malicious traffic to and from web applications. It is designed to protect applications from common web-based attacks such as SQL injection, cross-site scripting (XSS), file inclusion, and other threats defined in the OWASP Top 10. A WAF operates at the application layer (Layer 7 of the OSI model) and acts as a shield between external users and the application server.
WAFs are critical for safeguarding applications that are publicly accessible and frequently targeted by automated and manual attacks.
What is a Web Application Firewall?
A Web Application Firewall inspects HTTP and HTTPS traffic to identify and block potentially harmful requests before they reach a web application. Unlike traditional firewalls that focus on IP addresses and ports, WAFs analyze application-specific content such as URL parameters, headers, cookies, and payloads.
WAFs are typically deployed in one of the following modes:
- Reverse proxy: Intercepts requests and forwards only safe traffic to the application server
- Inline or transparent: Sits in-line with traffic flow but doesn’t modify headers
- Cloud-based WAF: Offered as a service, often with built-in DDoS protection and threat intelligence
WAFs use rule sets, signatures, behavioral models, and anomaly detection to enforce security policies.
Why WAFs matter
Modern web applications are often exposed to the internet, making them prime targets for exploitation. A WAF helps:
- Protect against common attacks like XSS, SQL injection, and remote file inclusion
- Prevent data breaches by blocking attempts to access sensitive information
- Support compliance with regulations like PCI DSS, HIPAA, and GDPR
- Safeguard APIs from abuse or misuse in REST and GraphQL environments
- Mitigate bots and automated attacks that probe for weaknesses
Without a WAF, web applications may be vulnerable to high-volume attacks that exploit insecure input handling, session management, or authentication mechanisms.
WAF vs. traditional firewalls and API gateways
While traditional network firewalls and intrusion prevention systems (IPS) provide perimeter defense, they do not inspect application-layer content deeply enough to block nuanced threats. WAFs complement these tools by offering:
- Deep packet inspection focused on web traffic
- Protection against OWASP Top 10 vulnerabilities
- Application-aware rule enforcement
- Fine-grained logging and alerting on application behavior
API gateways offer some overlapping capabilities like authentication, rate limiting, and basic validation, but WAFs specialize in detecting and blocking malicious payloads at the application layer.
Key features of a WAF
Effective WAFs offer a combination of the following features:
- Customizable rule sets to match application-specific needs
- Automatic threat updates based on global threat intelligence
- Bot protection and rate limiting to defend against abuse and scraping
- SSL/TLS decryption to inspect encrypted traffic
- Logging and reporting for audit trails and compliance
- Integration with SIEM and SOAR for incident response automation
Some advanced WAFs also include machine learning to detect novel or evasive attack patterns.
WAF in cloud-native environments
Cloud-native applications, often composed of APIs, microservices, and containerized workloads, require WAFs that are:
- Scalable and elastic to match auto-scaling architectures
- Integrated with CI/CD pipelines for testing and deploying security policies
- Compatible with Kubernetes ingress controllers and service meshes
- API-aware with the ability to inspect structured payloads and schema violations
Cloud providers like AWS, Azure, and Google Cloud offer native WAF services, and third-party solutions are also available for multicloud and hybrid environments.
How Orca Security helps
The Orca Cloud Security Platform enhances web application protection by providing visibility into cloud workloads, application configurations, exposed APIs, and misconfigured WAF rules. While Orca does not function as a WAF, it complements WAF solutions by identifying risks that WAFs alone cannot address.
With Orca, organizations can:
- Gain a full inventory of APIs and related web domains in their cloud estate, as well as API-related security and compliance risks
- Prioritizes risks by leveraging insights into APIs as well as risks found in cloud workloads, configurations and identities, to surface critical attack paths
- Continuously monitor API behavior and usage and alert teams to potentially unwanted API drift
- Detect web application vulnerabilities such as SQL injection and XSS
- Remediate risks fast and easily using AI-driven and assisted options
By combining contextual security insights with application-aware risk detection, Orca helps security teams harden their web-facing assets and maximize the effectiveness of their WAF deployments.
