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Introduction:
Bug bounty hunting has evolved into a sophisticated discipline, blending automated reconnaissance with manual exploitation techniques. Success in this field requires a deep understanding of web application security, network protocols, and the command-line tools that power modern security assessments.
Learning Objectives:
- Master fundamental reconnaissance and subdomain enumeration techniques using industry-standard tools.
- Understand and execute common web application attacks, including XSS, IDOR, and SSRF.
- Develop a methodology for automating repetitive tasks to maximize efficiency in bug bounty programs.
You Should Know:
1. Subdomain Enumeration with Amass and Subfinder
`amass enum -passive -d target.com -o subdomains.txt`
`subfinder -d target.com -o subfinder_results.txt`
`sort -u subdomains.txt subfinder_results.txt > final_subs.txt`
Step-by-step guide: Subdomain enumeration is the critical first step in discovering an organization’s attack surface. The Amass command performs passive enumeration using dozens of public data sources without sending direct traffic to the target. Subfinder utilizes similar passive sources to maximize coverage. The final sort command combines and deduplicates results from both tools, creating a comprehensive list for further analysis.
2. Content Discovery with FFUF
`ffuf -w /usr/share/wordlists/dirb/common.txt -u https://target.com/FUZZ -mc 200,301,302 -t 100`
`ffuf -w subdomains.txt:SUBDOMAIN -u https://SUBDOMAIN.target.com -mc 200,301,302,403 -t 100`
Step-by-step guide: FFUF is a fast web fuzzer that discovers hidden directories and files. The first command fuzzes for common paths on the main domain, checking for successful HTTP status codes. The second command takes your subdomain list and checks which are alive, helping to identify active targets. The `-t` flag controls threads for speed optimization.
3. XSS Payload Testing with Custom Scripting
`echo ‘‘ | tee xss_payloads.txt`
`cat xss_payloads.txt | while read payload; do curl -s “https://target.com/search?q=$payload” | grep -q “alert(1)” && echo “Vulnerable: $payload”; done`
Step-by-step guide: This simple pipeline tests for reflected XSS vulnerabilities. The first command creates a basic test payload. The second command iterates through payloads, sends them to a vulnerable parameter, and checks if the payload executes in the response. For production use, expand with URL encoding and more sophisticated payloads.
4. Identifying IDOR Vulnerabilities with Parameter Brute-forcing
`for i in {1..100}; do curl -s “https://api.target.com/user/$i/profile” -H “Authorization: Bearer token” | jq ‘.’ | grep -q “admin” && echo “Admin found: $i”; done`
Step-by-step guide: Insecure Direct Object Reference (IDOR) vulnerabilities occur when objects are accessed without proper authorization. This bash loop tests user IDs from 1 to 100, attempting to access each profile with an authenticated session. The `jq` command parses JSON responses, looking for privileged data that shouldn’t be accessible.
5. SSRF Testing with Interactsh
`ffuf -w params.txt:PARAM -u ‘https://target.com/endpoint?PARAM=http://interact.sh’ -mr “interact.sh”`
`curl ‘https://target.com/endpoint?url=http://burpcollaborator.net’`
Step-by-step guide: Server-Side Request Forgery (SSRF) testing involves making the server connect to external systems you control. The first command uses FFUF to fuzz parameters with an Interact.sh payload, which detects out-of-band interactions. The second command tests with Burp Collaborator. Monitor your endpoints for incoming connections from the target.
6. Automated Reconnaissance with Recon-ng
`recon-ng`
`marketplace install recon/domains-hosts/brute_hosts`
`modules load recon/domains-hosts/brute_hosts`
`set SOURCE target.com`
`run`
Step-by-step guide: Recon-ng is a full-featured web reconnaissance framework. After launching, install the brute_hosts module from the marketplace, load it, set the target domain, and execute. The module will perform subdomain brute-forcing using wordlists, expanding your attack surface beyond passive enumeration results.
7. JavaScript File Analysis for Hidden Endpoints
`curl -s https://target.com/main.js | grep -Eo “(https?://[^\”‘]|/[^\”‘])” | sort -u`
`subjs -l subdomains.txt -o js_urls.txt`
`cat js_urls.txt | while read url; do curl -s $url | grep -o “[a-zA-Z0-9_/-]\\.php\\|[a-zA-Z0-9_/-]\\.asp”; done`
Step-by-step guide: JavaScript files often contain hidden API endpoints and administrative functionality. The first command extracts URLs from a specific JS file. The second uses the subjs tool to find JavaScript files across all subdomains. The third pipeline searches these files for potential backend scripts that might contain vulnerabilities.
What Undercode Say:
- Methodology Outweigs Tools: The most successful hunters follow a consistent methodology rather than relying on tool outputs alone.
- Automation is Force Multiplier: Automating reconnaissance and initial vulnerability detection creates more time for deep manual testing.
- Understanding Business Logic: The highest-value bugs are often found in business logic flaws that scanners cannot detect.
The provided LinkedIn post celebrates a bug bounty win but reveals no technical details—this is typical in the industry where researchers protect their methodologies. True success comes from developing a systematic approach to application testing that combines automated reconnaissance with manual exploitation techniques. The most valuable findings often emerge from understanding application business logic rather than relying solely on automated scanners. Professional bug hunters spend significant time developing their toolchains and methodologies, which become their most guarded secrets.
Prediction:
As applications become more complex with AI integration and microservices architectures, bug bounty hunting will increasingly focus on API security and business logic flaws. Traditional vulnerabilities like XSS and SQLi will become less prevalent due to framework protections, while SSRF, race conditions, and authorization flaws will dominate high-value bounty awards. Hunters who master API testing and automate their reconnaissance pipelines will discover the most critical vulnerabilities in coming years.
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IT/Security Reporter URL:
Reported By: Shrujal Mandawkar – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
