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When starting in bug hunting, many newcomers struggle with identifying vulnerabilities, testing methodologies, and bypassing security mechanisms like 2FA or rate limiting. A well-structured vulnerability checklist helps streamline the process. Below is a detailed guide based on the GitHub – Az0x7/vulnerability-Checklist repository, along with practical commands and techniques.
You Should Know:
1. Login & Register Vulnerabilities
Common flaws in authentication systems include:
- Username Enumeration (Check HTTP responses for differences)
- Weak Password Policies (Brute-force testing)
- Account Lockout Bypass (Using IP rotation or header manipulation)
Commands & Tools:
Hydra brute-force attack hydra -L users.txt -P passwords.txt target.com http-post-form "/login:username=^USER^&password=^PASS^:F=incorrect" FFUF for username enumeration ffuf -w usernames.txt -u "https://target.com/login?username=FUZZ" -mr "Invalid username"
2. Bypassing 2FA (Two-Factor Authentication)
- Time-based OTP Reuse (Capture and reuse OTP before expiry)
- Response Manipulation (Change `”2fa_enabled”: true` to `false` in API requests)
- CSRF on 2FA Disable
Exploit Steps:
1. Intercept the 2FA request using Burp Suite.
2. Modify the response to skip 2FA verification.
3. Replay the request to gain access.
3. Rate Limit Bypass Techniques
- IP Rotation (Use proxies or Tor)
- Header Spoofing (Modify
X-Forwarded-For) - Parameter Pollution (Add duplicate params like
?user=test&user=admin)
Bash Script for IP Rotation:
!/bin/bash for ip in $(cat proxies.txt); do curl -x $ip -d "username=admin&password=guess" https://target.com/login done
4. API Vulnerability Testing
- Insecure Direct Object References (IDOR)
- Missing Rate Limits
- Exposed API Keys
Tool: Postman / Burp Suite
Testing IDOR with curl curl -H "Authorization: Bearer TOKEN" https://api.target.com/user/123 -vs
5. Tools for Web Exploitation
- Burp Suite (Proxy, Intruder, Repeater)
- SQLmap (Automated SQLi testing)
- Nmap (Port scanning for hidden services)
Example Nmap Scan:
nmap -sV --script=http-sql-injection target.com
What Undercode Say:
A structured methodology is crucial for efficient bug hunting. Focus on automation (with tools like FFUF, Hydra, SQLmap) and manual testing (Burp Suite manipulation). Always document findings and test for logical flaws beyond standard OWASP Top 10.
Prediction:
As web apps evolve, AI-driven security will become a double-edged sword—helping defenders patch faster but also enabling smarter automated attacks. Bug hunters must adapt by learning machine learning-based fuzzing and API abuse patterns.
Expected Output:
- Vulnerability Checklist: GitHub – Az0x7/vulnerability-Checklist
- Exploit Code: Hydra, FFUF, Curl, Nmap
- Defensive Mitigations: Rate limiting, strong 2FA, WAF rules
IT/Security Reporter URL:
Reported By: Yousef Ahmed – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
