Introduction
Cloudflare operates one of the world's largest edge networks, processing over 55 million HTTP requests per second across 310+ cities globally. Beyond performance optimization, Cloudflare provides enterprise-grade security controls that protect applications from threats at the edge — before malicious traffic reaches origin servers.
This guide covers production-ready security configurations for enterprises using Cloudflare.
Web Application Firewall (WAF)
Managed Rulesets
Cloudflare WAF includes pre-configured managed rulesets that block common attack patterns:
- OWASP Core Ruleset — Protection against OWASP Top 10 vulnerabilities
- Cloudflare Managed Ruleset — Proprietary rules updated continuously
- Exposed Credentials Check — Blocks logins with compromised passwords
Custom Rules
Enterprises should supplement managed rules with custom logic:
# Block requests with suspicious headers
(http.request.headers["user-agent"] contains "sqlmap")
or (http.request.uri.path contains "/admin" and not ip.src in {ALLOWED_IPS})
or (http.request.method eq "POST" and not http.request.uri.path starts_with "/api/")
Rate Limiting
Protect APIs and login endpoints from brute force attacks:
- Basic Rate Limiting — 10 requests per 10 seconds per IP
- Advanced Rate Limiting — Track by session, user, API key, or custom headers
- Challenge — Present CAPTCHA for suspected bots
- Block — Return 429 Too Many Requests
DDoS Protection
HTTP/HTTPS DDoS
Cloudflare automatically mitigates application-layer DDoS attacks:
- Adaptive Algorithms — Learn normal traffic patterns and detect anomalies
- Fingerprinting — Identify bot vs. human traffic
- Challenge Pages — JavaScript and CAPTCHA challenges filter out automated attacks
Network-Layer DDoS
Protection against SYN floods, UDP amplification, and other L3/L4 attacks happens automatically — no configuration required. Cloudflare absorbs attacks of 1+ Tbps without service degradation.
Bot Management
Bot Score
Cloudflare assigns every request a bot score (0-100):
- 0-29 — Automated (bot)
- 30-99 — Human or sophisticated bot
Super Bot Fight Mode
Enterprise customers can configure granular bot policies:
- Allow verified bots — Googlebot, Bingbot, monitoring services
- Challenge suspicious bots — Require JavaScript execution or CAPTCHA
- Block malicious bots — Scrapers, credential stuffers, inventory hoarders
Zero Trust Access (Cloudflare Access)
Application Access Policies
Protect internal applications without VPN:
policies:
- name: Admin Dashboard
decision: allow
conditions:
- email_domain: kerdos.in
- device_posture: managed
- mfa: required
Device Posture Checks
Enforce security requirements on user devices:
- Operating system up-to-date
- Disk encryption enabled
- Firewall active
- Corporate antivirus installed
SSL/TLS Configuration
Encryption Modes
- Off — Insecure, do not use
- Flexible — Cloudflare ↔ visitor encrypted, Cloudflare ↔ origin unencrypted (not recommended)
- Full — End-to-end encryption (certificate validation not enforced)
- Full (Strict) — Recommended for production; validates origin certificates
Minimum TLS Version
Set to TLS 1.2 minimum for enterprise applications. TLS 1.3 recommended for maximum performance and security.
HTTP Strict Transport Security (HSTS)
Enable HSTS to prevent protocol downgrade attacks:
Strict-Transport-Security: max-age=63072000; includeSubDomains; preload
Page Rules and Transform Rules
Security Headers
Inject security headers via Transform Rules:
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
X-XSS-Protection: 1; mode=block
Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline'
Referrer-Policy: strict-origin-when-cross-origin
Permissions-Policy: geolocation=(), microphone=(), camera=()
Origin Header Validation
Prevent CSRF by validating Origin and Referer headers on state-changing requests.
Monitoring and Alerts
Security Analytics
Cloudflare dashboard provides real-time insights:
- Requests blocked by WAF rules
- DDoS attack timelines
- Bot traffic percentages
- Country and ASN distributions
Notifications
Configure webhooks or email alerts for:
- DDoS attacks exceeding thresholds
- High error rates (5xx responses)
- Origin server health check failures
- SSL certificate expiration
Conclusion
Cloudflare's edge security platform offers comprehensive protection for enterprise applications — from DDoS mitigation to zero-trust access. Proper configuration of WAF rules, bot management, and SSL/TLS settings ensures robust security posture without compromising performance.
At Kerdos Infrasoft, we architect and implement Cloudflare security configurations for clients, protecting critical infrastructure while maintaining sub-50ms global response times.
Need help securing your applications? Contact us for a security audit.