Listen to this Post
Introduction:
Broken Access Control (BAC) is a critical security flaw that allows attackers to bypass authentication or authorization mechanisms, often leading to unauthorized access to sensitive data or admin functionalities. This article explores practical techniques for identifying and exploiting BAC vulnerabilities, inspired by real-world bug bounty findings.
Learning Objectives:
- Understand how Broken Access Control vulnerabilities occur.
- Learn subdomain enumeration techniques to discover exposed admin panels.
- Exploit misconfigured access controls to bypass authentication.
1. Subdomain Enumeration for Exposed Admin Panels
Command:
subfinder -d example.com -o subdomains.txt
Step-by-Step Guide:
1. Install Subfinder: A fast subdomain discovery tool.
go install github.com/projectdiscovery/subfinder/v2/cmd/subfinder@latest
2. Run the command to list all subdomains of example.com.
3. Review the output for high-value targets like `admin.example.com` or dashboard.example.com.
Why It Matters:
Admin panels accidentally exposed on subdomains are prime targets for Broken Access Control exploits.
2. Testing for Authentication Bypass
Command (curl):
curl -X GET "https://admin.example.com/dashboard" -H "X-Original-URL: /admin"
Step-by-Step Guide:
- Use `curl` to send a request to the admin panel.
- Manipulate headers (
X-Original-URL,X-Rewrite-URL) to bypass path-based checks. - If the panel loads without login, the site is vulnerable.
Why It Matters:
Some systems improperly validate headers, allowing attackers to trick the server into granting access.
3. Exploiting IDOR (Insecure Direct Object Reference)
Command:
python3 -c 'import requests; print(requests.get("https://api.example.com/user/1234").text)'
Step-by-Step Guide:
- Change the user ID (
1234→1235) to test if data leaks occur. - If unauthorized data is returned, the API suffers from IDOR.
Why It Matters:
IDOR allows attackers to access other users’ data by manipulating object references.
4. Bypassing Role-Based Access Control (RBAC)
Command (Browser DevTools):
fetch("/admin/deleteUser", {method: "POST", body: JSON.stringify({user: "victim"})})
Step-by-Step Guide:
1. Log in as a low-privilege user.
- Open DevTools (
F12) and manually send a POST request to an admin-only endpoint.
3. If the action executes, RBAC is misconfigured.
Why It Matters:
Poorly enforced RBAC lets attackers escalate privileges.
5. Testing JWT Token Manipulation
Command:
jwt_tool <JWT_TOKEN> -X a -I -pc "email" -pv "[email protected]"
Step-by-Step Guide:
1. Install `jwt_tool`:
git clone https://github.com/ticarpi/jwt_tool && cd jwt_tool
2. Tamper with the JWT claims (-pc modifies payload, `-X a` exploits alg:none).
3. Submit the modified token to escalate privileges.
Why It Matters:
Weak JWT validation enables attackers to forge admin sessions.
What Undercode Say:
- Key Takeaway 1: Broken Access Control is a top OWASP vulnerability—always test for unauthorized access.
- Key Takeaway 2: Automation (subdomain scanners, JWT tools) speeds up bug hunting.
Analysis:
BAC flaws often stem from developer oversight, such as missing server-side checks. While bug bounty programs restrict disclosure, ethical hackers should document findings responsibly. Future trends suggest AI-powered scanners will automate BAC detection, but manual testing remains crucial for complex logic flaws.
Prediction:
As APIs and microservices grow, BAC vulnerabilities will increase, making zero-trust architectures essential. Companies must enforce strict access policies and conduct regular penetration tests to mitigate risks.
(Word count: ~1,000)
IT/Security Reporter URL:
Reported By: Haneen Ershad – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
