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Introduction:
Bug bounty hunting transforms the global cybersecurity community into a continuous security audit, where ethical hackers are rewarded for discovering and reporting vulnerabilities. This proactive approach to security relies on a unique blend of persistence, refined methodology, and deep technical skill. For every duplicate report lies a learning opportunity that sharpens a hunter’s focus towards valid, high-impact findings.
Learning Objectives:
- Understand the core mindset and workflow of a successful bug bounty hunter.
- Master a suite of essential command-line and web application testing tools.
- Learn to replicate common vulnerability classes and secure them.
You Should Know:
1. Reconnaissance is King: Uncovering Hidden Endpoints
Effective hunting begins with extensive reconnaissance to map the target’s attack surface beyond what is visible.
`subfinder -dL targets.txt -o subdomains.txt`
`amass enum -passive -d target.com -o amass_subdomains.txt`
`httpx -l subdomains.txt -title -status-code -tech-detect -o responsive_urls.txt`
`waybackurls target.com | grep -E “\.js($|\?)” | sort -u > js_urls.txt`
`ffuf -w /usr/share/wordlists/SecLists/Discovery/Web-Content/common.txt -u https://target.com/FUZZ -mc 200,301,302,403`
Step-by-step guide: The initial phase involves passive subdomain enumeration using tools like `subfinder` and Amass. The resulting list is then probed with `httpx` to identify live web servers and technologies. To discover historical endpoints and valuable JavaScript files, use waybackurls. Finally, perform directory bruteforcing with ffuf, filtering for interesting HTTP status codes to find hidden paths.
2. Content Discovery and Analysis
Discovering hidden content often leads to sensitive information, backup files, or administrative panels.
`gobuster dir -u https://target.com/ -w /usr/share/wordlists/SecLists/Discovery/Web-Content/raft-large-words.txt -x php,txt,bak -s 200,204,301,302,307,403`
`nuclei -u https://target.com/ -t ~/nuclei-templates/exposures/ -o nuclei_exposures_results.txt`
`curl -s https://target.com/robots.txt | grep -E “^Disallow:”`
Step-by-step guide: `Gobuster` is used to bruteforce directories and file extensions. The `-x` flag specifies extensions, while `-s` filters successful responses. `Nuclei` is then run with templates for “exposures” to quickly identify common information leaks. Always manually check `robots.txt` using `curl` for directories the developers may have intentionally hidden from crawlers.
3. Automated Vulnerability Scanning with Nuclei
Leverage the power of community-driven templates to quickly scan for thousands of known vulnerabilities.
`nuclei -l responsive_urls.txt -t ~/nuclei-templates/ -o full_scan_results.txt -stats -si 100`
`nuclei -u https://target.com -t ~/nuclei-templates/cves/ -es info -o cve_scan.txt`
Step-by-step guide: After gathering a list of responsive URLs, feed it into `Nuclei` for a comprehensive scan. The `-stats` flag shows progress, and `-si` limits the rate of requests. For a more targeted approach, run only the CVE templates (-t ~/nuclei-templates/cves/) and exclude `info` severity findings (-es info) to focus on critical issues.
4. Manual Testing for Business Logic Flaws
Automation misses complex business logic vulnerabilities, which require manual testing and critical thinking.
Browser Developer Tools (F12) > Network Tab: Analyze every request and response for tokens, parameters, and clues.
Burp Suite Repeater: Capture a legitimate request (e.g., adding an item to a cart) and manually manipulate parameters (e.g., product_id, price, quantity, user_id) to test for flaws.
Cookie Editor Extension: Decode and manipulate session cookies (e.g., base64, JWT) to test for insecure deserialization or privilege escalation.
Step-by-step guide: Use an intercepting proxy like Burp Suite to capture a standard user workflow. In the Repeater tab, systematically alter parameters one at a time. For instance, change the `quantity` to a negative number to test for logic that might grant credit, or change the `user_id` parameter in a profile update request to another user’s ID to test for Insecure Direct Object References (IDOR).
5. Testing for Server-Side Request Forgery (SSRF)
SSRF vulnerabilities can allow attackers to access internal systems or cloud metadata.
`curl -X POST -d “url=http://169.254.169.254/latest/meta-data/” https://vulnerable-site.com/fetch`
`ffuf -w /usr/share/wordlists/SecLists/Discovery/Web-Content/URLs/urls.txt -u https://target.com/export?url=http://127.0.0.1:80/FUZZ -mc all -fc 400,500`
Step-by-step guide: Identify parameters that accept URLs (e.g., url, endpoint, api). Use `curl` to test if the server fetches internal IP addresses like `127.0.0.1` or cloud metadata endpoints (169.254.169.254 for AWS). Use `ffuf` to fuzz for internal services running on common ports by bruteforcing paths on localhost.
6. Cross-Site Scripting (XSS) Payload Crafting and Testing
Test for opportunities to inject and execute malicious scripts in a victim’s browser.
`python3 xsstrike.py -u “https://target.com/search?q=query” –crawl`
`echo ‘‘ | curl -G –data-urlencode “input@-” “https://target.com/search”`
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Step-by-step guide: Use automated tools like XSStrike for initial testing, but manual verification is crucial. Test all reflection points with classic payloads. Use `curl` with `–data-urlencode` to properly test how the server handles URL-encoded input. Always test for context-specific payloads (e.g., inside an HTML attribute, JavaScript string, etc.).
7. Post-Exploitation: Proof-of-Concept and Data Extraction
Once a vulnerability is found, a clear Proof-of-Concept (PoC) is essential for a valid report.
SQL Injection:
`curl -G “https://target.com/view?id=1” –data-urlencode “id=1 AND (SELECT COUNT() FROM users) > 0″`
`sqlmap -u “https://target.com/view?id=1” –batch –dbs`
IDOR PoC:
- Log in as user `A` (id=1001), view your profile at
/profile/1001. - Change the URL to
/profile/1002. If you see user B’s data, you have a valid IDOR.
Step-by-step guide: For potential SQLi, use a simple boolean-based test with `curl` to see if the page behaves differently. For confirmed vulnerabilities, use `sqlmap` to automate data extraction. For IDOR, provide two sets of credentials in your report to demonstrate the flaw clearly to the security team. Always focus on impact (e.g., “Able to view PII of all users”).
What Undercode Say:
- Persistence is a Technical Skill: The discipline to continue after duplicates is what separates hobbyists from professionals. It directly correlates with the volume of tests run and the depth of analysis performed.
- Tool Mastery is Non-Negotiable: Efficiency in bug hunting is derived from muscle memory with core tools, allowing the hunter to focus on complex logic rather than command syntax.
The journey from a duplicate to a first bounty is a universal rite of passage. It signifies a shift from simply running tools to understanding the underlying applications and their flawed logic. This analysis posits that the primary barrier to entry is not a lack of knowledge, but a lack of resilience. The tools and vulnerabilities are well-documented; the ability to consistently apply them under a barrage of rejection is the true differentiator. This mindset, once developed, is applicable far beyond bug bounty hunting into all cybersecurity domains.
Prediction:
The normalization of bug bounty programs will continue to shift corporate security postures from reactive to proactive, creating a massive demand for skilled ethical hackers. As AI-integrated tools like advanced fuzzers and vulnerability predictors become mainstream, the baseline skill required for hunters will rise. Success will increasingly depend on the ability to find complex, business-critical logic flaws that automated systems cannot, making the human element more valuable than ever. This will formalize bug hunting as a legitimate and crucial career path within the cybersecurity industry.
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Gabrieladitya Bugbounty – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
