CVE-2024-5124

Timing attack in password comparison allows attackers to guess passwords.

• CVSS 7.5
• CWE-203
• Authentication, Authorization, and Session Management
• Remote

A timing attack vulnerability exists in the gaizhenbiao/chuanhuchatgpt repository, specifically within the password comparison logic. The vulnerability is present in version 20240310 of the software, where passwords are compared using the '=' operator in Python. This method of comparison allows an attacker to guess passwords based on the timing of each character's comparison. The issue arises from the code segment that checks a password for a particular username, which can lead to the exposure of sensitive information to an unauthorized actor. An attacker exploiting this vulnerability could potentially guess user passwords, compromising the security of the system.

CVE

CVE-2024-5124

CWE

CWE-203

CVSS base score

7.5

Published

2024-06-06

OWASP

A03 Sensitive Data Exposure

Orthogonal defect classification

Timing/Serialization

Code defect classification

Timing Issues

Category

Authentication, Authorization, and Session Management

Subcategory

Insecure Authentication Mechanisms

Accessibility scope

Remote

Impact

Unauthorized Access

Affected component

Python

Solution

Upgrade to a version that uses a constant-time comparison function for password verification, such as `hmac.compare_digest`, to mitigate timing attacks.

def verify_password(stored_password, provided_password):
    # VULNERABLE: This code is susceptible to crypto weakness
    if stored_password == provided_password:
        return True
    return False

stored_password = "securepassword"
provided_password = "userinputpassword"

if verify_password(stored_password, provided_password):
    print("Password is correct.")
else:
    print("Password is incorrect.")

import hmac

def verify_password(stored_password, provided_password):
    # SECURE: This version prevents crypto weakness
    return hmac.compare_digest(stored_password, provided_password)

stored_password = "securepassword"
provided_password = "userinputpassword"

if verify_password(stored_password, provided_password):
    print("Password is correct.")
else:
    print("Password is incorrect.")

# Example payload to exploit the timing attack vulnerability
import time

def guess_password(stored_password):
    alphabet = "abcdefghijklmnopqrstuvwxyz"
    guessed_password = ""
    
    for _ in range(len(stored_password)):
        for char in alphabet:
            # Simulate sending the password guess to the server
            start_time = time.time()
            # This would be the vulnerable comparison
            if stored_password[:len(guessed_password) + 1] == guessed_password + char:
                elapsed_time = time.time() - start_time
                print(f"Trying: {guessed_password + char} (Time: {elapsed_time:.6f}s)")
                guessed_password += char
                break

    return guessed_password

# Example usage
stored_password = "securepassword"
guessed = guess_password(stored_password)
print(f"Guessed password: {guessed}")

@misc{vaitp:cve20245124,
  title        = {{Timing attack in password comparison allows attackers to guess passwords.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2024},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2024-5124},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2024-5124/}}
}