Web applications are the beating heart of modern business. Orders, payments, user registrations, data storage, and internal communication all flow through them. The more valuable your service, the more it attracts hackers.
Classic DDoS floods aren’t the main threat anymore. Today’s attackers prefer smarter methods: SQL injection, XSS, brute force on APIs, and credential stuffing. Automated bots can scan thousands of websites in minutes, hunting for weak spots.
What is a WAF?
A Web Application Firewall (WAF) is like a traffic cop for your HTTP(S) traffic. It inspects every request and decides whether to let it through or block it before it hits your app.
Unlike a network firewall that only filters IPs and ports, a WAF understands the structure of web traffic. For example:
- A SQL string injected into a search bar instead of normal text.
- Hundreds of password attempts per second on a login form.
Both cases get flagged and blocked before they ever reach your database or app.
Types of Attacks Stopped by WAF
- SQL Injection – inserting malicious queries to steal or alter data.
- XSS (Cross-Site Scripting) – injecting scripts that hijack sessions or steal user data.
- Brute Force & Session Hijacking – endless login attempts and token theft.
- API Attacks – overloading or exploiting API endpoints.
- Application-Layer DDoS – swarming the site’s logic instead of the network.
- CMS & Framework Exploits – taking advantage of known holes in popular systems.
With a WAF in place, these threats get filtered out before they can wreck your app, steal data, or tank uptime.
How WAF Works
- Signature-based analysis – matches known attack patterns.
- Behavioral analysis – flags abnormal activity, like login floods.
- Machine learning – learns your app’s traffic profile to cut down false positives.
- Real-time filtering – blocks bad requests before they ever hit your server.
WAF vs. No WAF: Side-by-Side
| Scenario | No WAF | With WAF |
|---|---|---|
| SQL Injection | Query hits the DB, data gets stolen | Blocked at the edge |
| XSS Attack | Malicious script runs, cookies hijacked | Filtered before page load |
| Brute Force | Unlimited login attempts | IP blocked on suspicious behavior |
| API Flood | Massive requests overload the service | Abnormal traffic stopped at entry |
| App-Layer DDoS | Site crashes, revenue lost | Suspicious traffic filtered out |
| CMS Exploits | Zero-day hits before patch | Common exploits blocked by rules |
Why WAF Matters Now
Security reports paint a clear picture: web applications are under nonstop fire. Millions of API attacks, billions of security events, and record-breaking request floods show why WAF security is no longer optional.
CDN + WAF: The Perfect Combo
A Content Delivery Network (СDN) accelerates performance and reduces server load. A WAF filters web threats. Together, they deliver speed and security in one package. At Serverspace, you can activate both directly in your control panel within minutes—no extra software needed.
Common WAF Mistakes
- Leaving default settings untouched.
- Thinking WAF solves everything (it doesn’t replace patching).
- Ignoring logs that reveal ongoing attacks.
- Skipping rule updates.
- Going straight into block mode without tuning.
Business Benefits of WAF
- Lower risk of downtime and data breaches.
- Compliance with standards like PCI DSS.
- Less stress on IT and dev teams.
- Seamless integration with CDN security.
Bottom line: A WAF is a must-have for any web app. Combined with CDN acceleration, it keeps your site fast, resilient, and protected against today’s OWASP Top-10 and beyond.