How Hack: Business Logic Errors in Bug Bounty Hunting

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A quick bounty of $250 was awarded for identifying a Business Logic Error on HackerOne. The report was submitted at 1:03 AM, triaged by 3:13 AM, and rewarded by 4:25 AM. This highlights the importance of understanding business logic flaws in bug bounty hunting.

You Should Know: Exploiting Business Logic Errors

Business logic errors occur when an application’s workflow can be manipulated due to flawed design. Attackers exploit these gaps to bypass intended functionality, leading to unauthorized actions.

Common Business Logic Vulnerabilities:

  1. Price Manipulation – Altering payment values before checkout.
  2. Authentication Bypass – Skipping login steps by tampering with requests.
  3. Infinite Actions – Exploiting loops (e.g., unlimited coupon usage).
  4. Privilege Escalation – Gaining admin access via flawed role checks.

Testing Business Logic Flaws (Hands-On Commands)

1. Intercepting Requests with Burp Suite

 Start Burp Suite (Linux)
java -jar burpsuite_pro_vX.X.X.jar

– Modify parameters (e.g., `price=100` → price=0.01).

2. Automated Testing with OWASP ZAP

 Launch ZAP (Linux/Windows)
./zap.sh  Linux
zap.bat  Windows

– Use Active Scan to detect logic flaws.

3. Bypassing Rate Limits

 Simulate multiple requests (Linux)
for i in {1..100}; do curl -X POST "https://target.com/api/coupon" -d "code=TEST123"; done

– Check if the coupon is reused despite rate-limiting.

4. Detecting IDOR (Insecure Direct Object Reference)

 Change user_id parameter (e.g., ?user_id=100 → ?user_id=101)
curl "https://target.com/profile?user_id=101"

– If data leaks, it’s an IDOR flaw.

5. Testing for Workflow Bypass

 Skip steps by directly accessing endpoints
curl -X POST "https://target.com/checkout/confirm" --data "confirm=true"

– If the order processes without payment, it’s a logic flaw.

What Undercode Say

Business logic bugs are goldmines in bug bounty programs because they often go unnoticed by automated scanners. Mastering manual testing with tools like Burp Suite, Postman, and cURL is crucial.

Key Linux Commands for Bug Hunters:

 Monitor HTTP traffic
tcpdump -i eth0 -w traffic.pcap

Fuzz parameters with ffuf 
ffuf -u "https://target.com/FUZZ" -w wordlist.txt

Check API responses 
curl -I "https://api.target.com/v1/user"

Brute-force endpoints 
gobuster dir -u https://target.com -w /path/to/wordlist

Windows Equivalent (PowerShell):

 Test API endpoints 
Invoke-WebRequest -Uri "https://target.com/api" -Method POST

Check for open ports 
Test-NetConnection -ComputerName target.com -Port 443

Expected Output:

A well-tested business logic flaw report should include:

  • Steps to Reproduce (clear, concise).
  • Impact (e.g., financial loss, data breach).
  • Proof of Concept (PoC) (screenshots, videos).

Keep hunting, and always think outside the code! 🚀

Expected Output:

A detailed bug report demonstrating a business logic flaw, including HTTP request/response logs, exploitation steps, and mitigation recommendations.

References:

Reported By: Mamunwhh Bugbounty – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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