Every bug bounty hunter has curl installed. Few use it to its full potential. While Burp Suite and custom scripts get the limelight, curl remains the quiet workhorse — scriptable, lightweight, and available on every target's infrastructure you'll ever test.

This article goes beyond -X POST -d "data". We'll cover real-world workflows: fuzzing, bypassing WAFs, pipeline automation, and creative exploitation techniques that save you time and find bugs others miss.

1. The Recon Foundation

Before you fire off exploits, you need surface area. curl shines here because it's stateless — perfect for shell loops and parallelization.

Subdomain Discovery via Certificate Transparency

curl -s "https://crt.sh/?q=%25.target.com&output=json" | jq -r '.[].name_value' | sort -u

This queries crt.sh’s JSON endpoint for all certificates issued to *.target.com. Combine with jq for clean output — no rate limiting, no API key.

Header Fingerprinting

curl -sI https://www.target.com | grep -i -E "server|x-powered-by|x-frame-options|content-security-policy|set-cookie"