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Introduction
Bug bounty hunting is a lucrative field, but many hunters miss critical vulnerabilities due to oversight or lack of awareness. Om Bhanushali’s recent €100 payout highlights a common yet frequently ignored bug that can yield quick rewards. This article dissects the vulnerability, provides actionable commands for testing, and explains mitigation strategies.
Learning Objectives
- Identify the overlooked vulnerability that leads to quick bug bounty payouts.
- Learn how to test for this bug using verified Linux/Windows commands.
- Understand mitigation techniques to secure applications against this flaw.
1. The Vulnerability: Misconfigured API Endpoints
Many applications expose internal APIs without proper authentication checks, allowing unauthorized access.
Command to Test:
curl -X GET "https://target.com/api/internal/users" -H "Authorization: Bearer null"
Step-by-Step Guide:
1. Use `curl` to probe API endpoints.
2. Replace `target.com` with the domain you’re testing.
- Check if the endpoint responds with sensitive data when no or invalid tokens are supplied.
- If data leaks, report it as an Unauthorized Data Access issue.
2. Exploiting Improper Error Handling
Verbose error messages can reveal system details, aiding attackers.
Command to Test:
curl -X POST "https://target.com/login" -d "username=admin&password=wrongpass"
Step-by-Step Guide:
1. Send incorrect credentials to login endpoints.
- Observe if the error message discloses stack traces, database names, or server versions.
- Report as Information Disclosure if excessive details are exposed.
3. IDOR (Insecure Direct Object Reference) Testing
Many applications fail to validate user permissions when accessing resources.
Command to Test:
curl -X GET "https://target.com/api/user/1234/profile" -H "Cookie: session=valid_session"
Step-by-Step Guide:
1. Log in and capture your session cookie.
- Modify the user ID in the URL (e.g., `1234` →
1235). - If you access another user’s data, report it as IDOR.
4. SSRF (Server-Side Request Forgery) Exploitation
Internal service interactions can be abused to access restricted systems.
Command to Test:
curl -X POST "https://target.com/fetch" -d "url=http://169.254.169.254/latest/meta-data"
Step-by-Step Guide:
1. Test endpoints that fetch external URLs.
- Replace the URL with internal AWS/Azure metadata endpoints.
- If the server responds with internal data, report as SSRF.
5. Command Injection in Forgotten Legacy Systems
Older systems may execute unsanitized user input.
Command to Test:
curl "https://target.com/run?cmd=whoami"
Step-by-Step Guide:
1. Look for endpoints that execute system commands.
2. Inject basic commands (`whoami`, `ls`, `id`).
- If the server executes them, escalate to RCE (Remote Code Execution).
What Undercode Say
- Key Takeaway 1: Many high-paying bugs are simple misconfigurations, not complex exploits.
- Key Takeaway 2: Automated scanners miss these issues; manual testing is crucial.
Analysis:
Bug bounty success hinges on persistence and attention to detail. While many hunters focus on XSS and SQLi, low-hanging fruit like IDOR and SSRF often go unnoticed. Platforms like HackerOne and Zerocopter prioritize these reports due to their high impact.
Prediction
As APIs become more prevalent, misconfigurations and authentication flaws will dominate bug bounty payouts. Companies will invest more in API security, but hunters who master these vulnerabilities early will reap the rewards.
Happy Hunting! 🚀
IT/Security Reporter URL:
Reported By: Tsxninja 100 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
