How and When To Use A Web-Based Firewall

February 15, 2025 - by Paul Tomori

Web application security has become increasingly important in today’s digital environment, with cyber threats evolving and targeting vulnerabilities in websites, particularly those built on SQL databases or which use commonly-used protocols like WordPress. One of the most effective tools to protect your site from these threats is a Web Application Firewall (WAF). A WAF acts as a protective shield, filtering and monitoring HTTP traffic between a web application and the internet.

Without proper safeguards, sites are susceptible to a range of attacks, including malicious bots, Distributed Denial-of-Service (DDoS) attacks, and SQL injection exploits. These threats can disrupt your site, compromise sensitive data, and overwhelm your server’s resources. That’s where a WAF steps in to provide essential defense mechanisms.

In this post, we’ll explore 10 key things a WAF can do to safeguard your site, reduce server load, and enhance overall performance. Whether you’re dealing with persistent bots or concerned about zero-day vulnerabilities, a WAF is an indispensable tool for web security.

1. Block Malicious Bots and Crawlers

   A WAF inspects incoming traffic and blocks requests from known malicious bots or web scrapers trying to harvest your content, exploit vulnerabilities, or overload your server.

   How it helps:

   • Protects your site from automated attacks, including credential stuffing, brute-force login attempts, and content scraping.
   • Ensures only legitimate search engine bots (like Googlebot) can crawl your site.


2. Mitigate DDoS Attacks

   WAFs detect and block Distributed Denial-of-Service (DDoS) attacks by identifying patterns of excessive traffic and rate-limiting or blocking offending IPs before they reach your server.

   How it helps:

   • Keeps your site online by filtering out harmful traffic while allowing legitimate users to access your site.
   • Reduces server load during an attack.
   
   
3. Prevent SQL Injection Attacks

   A WAF identifies and blocks SQL injection attempts, where attackers try to manipulate your site's database through malicious input in forms or URLs.

   How it helps:

   • Protects sensitive data (like user credentials) from being stolen or modified.
   • Prevents attackers from accessing, corrupting, or deleting your database.
   
   
4. Block Cross-Site Scripting (XSS) Attacks

   WAFs detect and block XSS attacks, where attackers inject malicious scripts into your site to steal user data or perform unauthorized actions.

   How it helps:

   • Prevents malicious scripts from running in users’ browsers, protecting your site's reputation and users' data.
   • Blocks phishing attempts or unauthorized redirects.
   
   
5. Protect Against Zero-Day Vulnerabilities

   A WAF can provide virtual patching by blocking known exploit patterns for vulnerabilities, even before a patch is available for your application.

   How it helps:

   • Buys time to apply software updates or patches while keeping your site protected.
   • Reduces the risk of being exploited during the critical window before a patch is released.
   
   
PROTIPS: Use CloudFlare To Shield Your Site
Cloudflare is a global cloud service provider that offers security, performance, and reliability solutions for websites and applications. It acts as a reverse proxy, sitting between a website's server and its visitors to filter traffic, block threats, and accelerate loading times. Cloudflare provides services such as DDoS protection, Web Application Firewall (WAF), content delivery network (CDN), and secure DNS. With a vast global network, Cloudflare helps ensure websites stay fast, secure, and available to users worldwide.
• Blocks malicious traffic using advanced threat intelligence and real-time updates for superior protection.
• Offers DDoS protection to keep websites online during large-scale attacks without performance loss.
• Provides customizable firewall rules to suit specific application security needs and policies.
• Prevents common web vulnerabilities with built-in OWASP Top 10 protections.
• Accelerates web traffic with integrated caching and performance optimization features.
• Features easy-to-use dashboards for real-time monitoring and security analytics.
• Automatically updates security patches, reducing the risk of zero-day vulnerabilities.
• Supports bot management to block harmful automated traffic and prevent credential stuffing attacks.
6. Enforce Rate Limiting

   WAFs can enforce rate limiting rules to restrict how many requests a single IP can make within a given time frame. This is especially useful for protecting login pages, forms, and API endpoints.

   How it helps:

   • Prevents abuse from bots attempting credential stuffing or brute-force attacks.
   • Protects your server from being overloaded by too many requests from a single source.
   
   
7. Block File Upload Exploits

   Many attacks involve uploading malicious files or scripts to a website. A WAF can inspect uploaded files and block those that match known malicious patterns.

   How it helps:

   • Prevents attackers from uploading web shells, malware, or other malicious files.
   • Protects your server from being compromised through vulnerable file upload points.
   
   
8. Filter Out Spam and Bad Requests

   WAFs can block spammy or malformed requests, such as those with unusually long URLs, suspicious query strings, or headers that don’t match typical browser behavior.

   How it helps:

   • Reduces spam and bad traffic that can clutter your logs or trigger errors.
   • Helps ensure your site only processes legitimate traffic.
   
   
9. Block Cross-Site Request Forgery (CSRF) Attacks

   A WAF can detect and block CSRF attacks, where attackers trick users into performing actions they didn’t intend by exploiting their authenticated session.

   How it helps:

   • Prevents unauthorized actions like changing passwords or transferring funds in user accounts.
   • Protects sensitive areas of your site that require user authentication.
   
   
10. Provide Detailed Traffic Analytics

    Most WAFs come with a dashboard that offers detailed insights into your traffic, including:

    • How many requests were blocked.
    • Types of attacks attempted (e.g., XSS, SQL injection).
    • IP addresses or regions generating the most threats.
    
    

    How it helps:

    • Helps you understand attack patterns and identify high-risk areas of your site.
    • Enables you to fine-tune security settings based on real-time data.
    
    

Bonus: Reduce Server Load and Improve Performance

If you are suffering brownouts, intermittent downtime of your website, or slowness with your site, contact us today for help migrating to a WAF. We have expert-level knowledge on how to migrate to CloudFlare and how to configure it optimally to make your website hum. Leave it to the experts.

Do you like our technical "proactive" approach to business? Drop us a line. We look forward to working with like-minded people and companies.