Cloudflare is an excellent tool for securing web applications, offering enterprise-level WAF, CDN, and reverse proxy functionalities. If you’re not using it, you should start today. Below are essential WAF rules to block malicious traffic effectively.
1. Block Requests Without a User Agent
Legitimate browsers and clients always include a user agent. Automated scripts or malicious bots often omit this header.
Cloudflare WAF Rule:
(http.user_agent eq "")
Action: Block
2. Block Known Malicious User Agents
Tools like SQLmap, cURL, wget, Burp Suite, and Nuclei are commonly used in attacks.
Cloudflare WAF Rule:
(http.user_agent contains "sqlmap") or (http.user_agent contains "curl") or (http.user_agent contains "wget") or (http.user_agent contains "burp") or (http.user_agent contains "nuclei")
Action: Block
3. Geo-Blocking High-Risk Countries
Malicious traffic often originates from:
- North Korea (.kp)
- China (.cn)
- Russia (.ru)
- Ukraine
- Iceland
Cloudflare WAF Rule:
(ip.geoip.country in {"KP" "CN" "RU" "UA" "IS"})
Action: Block
4. Block Tor Exit Nodes
Cloudflare provides a list of Tor exit nodes. Enable this feature to block anonymous traffic.
Cloudflare WAF Rule:
(cf.threat_score gt 10)
Action: Block
5. Rate Limiting to Prevent Brute Force Attacks
Set rate limits on login pages to prevent credential stuffing.
Cloudflare Rate Limiting Rule:
(http.request.uri.path contains "/login") and (cf.bot_management.verified_bot eq false)
Threshold: 10 requests per minute
Action: Block
You Should Know:
- Testing WAF Rules: Use `curl` with custom headers to verify rules:
curl -A "sqlmap" https://yourwebsite.com
- Logging Blocked Requests: Enable Cloudflare logs to analyze attacks.
- Dynamic Blocking: Use Cloudflare’s Firewall Analytics to fine-tune rules.
- Bypassing False Positives: Whitelist trusted IPs using:
(ip.src in {1.1.1.1 2.2.2.2})
What Undercode Say
Cloudflare’s WAF is a powerful tool to mitigate automated attacks, but it’s not a silver bullet. Combine it with:
– Fail2Ban (Linux) for additional IP blocking:
fail2ban-client set cloudflare banip <IP>
– Nginx/Apache ModSecurity for deeper request inspection.
– Windows Firewall rules to block high-risk countries:
New-NetFirewallRule -DisplayName "Block China" -RemoteAddress 1.0.0.0/8 -Action Block
– Linux IPTables for manual blocking:
iptables -A INPUT -s 1.2.3.4 -j DROP
Prediction
As cyber threats evolve, Cloudflare will likely integrate AI-driven attack detection, reducing false positives while improving threat intelligence.
Expected Output:
A hardened Cloudflare WAF setup with automated blocking for malicious traffic, reducing attack surface significantly.
Relevant URLs:
References:
Reported By: Activity 7325232671264071680 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
