Effective reconnaissance is the foundation of successful bug bounty hunting. Here are the top 10 tools every researcher should have in their toolkit.
1. Burp Suite
The industry-standard web proxy and scanner. Burp Suite Community is free and powerful; the Professional version adds automated scanning. Use it for:
- Intercepting and modifying HTTP requests
- Scanning for common vulnerabilities
- Intruder for brute-force and fuzzing
- Repeater for manual request manipulation
2. Nmap
The network mapper — essential for discovering live hosts, open ports, and services. Key scan types:
-sV— version detection-sC— default script scan-O— OS detection--script vuln— vulnerability detection scripts
3. Amass
In-depth attack surface mapping and subdomain discovery. Amass uses multiple data sources including DNS, certificates, APIs, and search engines to build a comprehensive map of the target's attack surface.
4. httpx
Fast and multi-threaded HTTP probe tool. After discovering subdomains with Amass or Subfinder, use httpx to:
- Check which hosts are alive
- Extract titles, status codes, and content types
- Identify technology stacks
- Export results for further analysis
5. Subfinder
Fast subdomain discovery tool that uses passive sources. Subfinder is part of the ProjectDiscovery ecosystem and integrates well with other tools in the workflow.
6. OWASP ZAP
The Zed Attack Proxy — a free, open-source alternative to Burp Suite. ZAP is maintained by OWASP and includes:
- Automated scanners
- Passive scanning
- API scanning
- CI/CD integration
7. crt.sh
Certificate Transparency log search — a goldmine for subdomain discovery. Search by domain to find all certificates issued for that domain and its subdomains. Many forgotten or undocumented subdomains appear here first.
8. SQLMap
Automated SQL injection detection and exploitation tool. SQLMap can:
- Detect SQL injection vulnerabilities
- Enumerate database structures
- Extract data from databases
- Execute OS commands (in some configurations)
9. Fingerprintx
Service fingerprinting tool that identifies running services and their versions. Useful for identifying potentially vulnerable services during reconnaissance.
10. Naabu
Fast port scanner designed for reconnaissance workflows. Naabu is lightweight and integrates with other ProjectDiscovery tools. Use it for:
- Fast port scanning
- STDIN/STDOUT workflow integration
- Identified ports feed into service enumeration
Putting It Together
A typical reconnaissance workflow:
- Subdomain discovery: Subfinder + Amass + crt.sh
- Host verification: httpx to check which subdomains are alive
- Port scanning: Naabu or Nmap for open ports
- Service enumeration: Nmap -sV, Fingerprintx
- Web scanning: Burp Suite or OWASP ZAP for application testing
Important Note
Always ensure you have proper authorization before scanning. In bug bounty programs, read the scope carefully — some programs restrict certain tools or scanning techniques. Unauthorized scanning can get you disqualified or banned.