Have you ever imagined a situation where an eavesdropper intercepts your communication, posing a threat to your confidentiality and integrity? That's precisely what the CVE-2024-8935 vulnerability brings to the table. This post aims to provide insights into this vulnerability, its consequences, and ways to mitigate it.

Exploring the CVE-2024-8935 Vulnerability (CWE-290)

The Common Vulnerabilities and Exposures (CVE) identifier CVE-2024-8935 refers to an Authentication Bypass by Spoofing vulnerability, which is also known as CWE-290. It primarily affects systems that employ the Diffie Hellman algorithm, a widely adopted cryptographic method responsible for secure key exchange between users.

This vulnerability can lead to a denial of service and compromise the confidentiality and integrity of controllers. It occurs when an attacker performs a Man-In-The-Middle attack, intercepting the communication between the controller and the engineering workstation.

How the Vulnerability Affects Authentication and Communication

When a valid user tries to establish a communication session using the Diffie Hellman algorithm, the vulnerability permits the attacker to bypass authentication processes undetected. This essentially allows the attacker to spoof the legitimate user's identity and manipulate or tamper with the exchanged data.

The primary reason behind the vulnerability is that the Diffie Hellman algorithm does not provide protection against MITM attacks, resulting in potential risks to the confidentiality and integrity of encrypted data.

Here is an example of a code snippet that uses the vulnerable Diffie Hellman key exchange

# Import required libraries
import hashlib
import random

# Function for calculating the shared secret key
def calc_secret_key(private_key, public_key, prime):
    return (public_key ** private_key) % prime

# Diffie Hellman key exchange process
def diffie_hellman_key_exchange(prime, base, private_key):
    return (base ** private_key) % prime

# Initial setup - defining prime and base values
prime = 23
base = 5

# Alice and Bob generate their private keys
alice_private_key = random.randint(1, 100)
bob_private_key = random.randint(1, 100)

# Alice and Bob calculate their public keys
alice_public_key = diffie_hellman_key_exchange(prime, base, 
alice_private_key)
bob_public_key = diffie_hellman_key_exchange(prime, base, 
bob_private_key)

# Alice and Bob calculate their shared secret keys
alice_secret_key = calc_secret_key(alice_private_key, 
bob_public_key, prime)
bob_secret_key = calc_secret_key(bob_private_key, 
alice_public_key, prime)

# Vulnerability - MITM attack on key exchange
# Attacker intercepts Alice's and Bob's public keys
attacker_public_key = random.randint(1, 100)
attacker_alice_shared_key = calc_secret_key(attacker_public_key, 
alice_public_key, prime)
attacker_bob_shared_key = calc_secret_key(attacker_public_key, 
bob_public_key, prime)

In this code snippet, the attacker can easily intercept Alice's and Bob's public keys, thus compromising the confidentiality and integrity of the shared secret keys.

Exploit Details & Countermeasures

Due to the inherent vulnerability in the Diffie Hellman algorithm, defending against MITM attacks is crucial. Implementing robust countermeasures can help reduce the likelihood of such attacks.

1. Public Key Infrastructure (PKI): Using digital certificates issued by trusted Certificate Authorities (CAs) is a significant step in ensuring the authenticity and integrity of exchanged public keys.

2. Verification Methods: Implement verification methods like digital signatures or message authentication codes to validate the public keys' integrity before using them for sharing secrets.

3. Secure Channels: Implement secure communication channels, such as using Transport Layer Security (TLS), to prevent MITM attacks.

4. Frequent Key Rotation: Rotating cryptographic keys more frequently can reduce the impact of key compromise.

- CVE-2024-8935 Details
- CWE-290: Authentication Bypass by Spoofing
- NIST National Vulnerability Database: CVE-2024-8935

In conclusion, understanding the CVE-2024-8935 vulnerability is essential for protecting confidentiality and integrity in any system that uses the Diffie Hellman algorithm. By applying the countermeasures discussed, organizations can minimize the chances of encountering the detrimental effects of MITM attacks. Maintaining these best practices will go a long way toward securing your operations and preserving trust in your communication channels.

Timeline

Published on: 11/13/2024 04:10:09 UTC