CVE-2024-3596: FreeRADIUS Auth Bypass Vulnerability

CVE-2024-3596 Overview

RADIUS Protocol under RFC 2865 is susceptible to forgery attacks by a local attacker who can modify any valid Response (Access-Accept, Access-Reject, or Access-Challenge) to any other response using a chosen-prefix collision attack against the MD5 Response Authenticator signature.

Critical Impact

The vulnerability allows attackers to intercept and modify authentication responses, leading to unauthorized access or denial of service.

Affected Products

• freeradius freeradius
• broadcom brocade_sannav
• broadcom fabric_operating_system
• sonicwall sonicos

Discovery Timeline

• Not Available - Vulnerability discovered by Not Available
• Not Available - Responsible disclosure to freeradius
• Not Available - CVE CVE-2024-3596 assigned
• Not Available - freeradius releases security patch
• 2024-07-09 - CVE CVE-2024-3596 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2024-3596

Vulnerability Analysis

The vulnerability resides in the RADIUS protocol's use of the MD5 Response Authenticator. Attackers can leverage chosen-prefix collisions in MD5 hashes to forge authentication responses, thereby circumventing security measures intended to enforce network access control.

Root Cause

A weak cryptographic mechanism in the RADIUS protocol, specifically the MD5 hashing algorithm, which is prone to collision attacks.

Attack Vector

Network-based exploitation where the attacker has local access and can intercept or modify RADIUS packets.

# Example exploitation code (sanitized)
import hashlib

# Simulate MD5 collision attack
fake_response = b"Fake-Response"
legit_response = b"Legit-Response"

# Forgery
if hashlib.md5(fake_response).digest() == hashlib.md5(legit_response).digest():
    print("Potential Forgery Detected")

Detection Methods for CVE-2024-3596

Indicators of Compromise

• Unexpected RADIUS access requests
• Anomalies in RADIUS access logs
• Discrepancies in user authentication records

Detection Strategies

Utilize packet inspection and anomaly detection systems to monitor RADIUS traffic for unusual patterns indicative of forgery or collision attempts.

Monitoring Recommendations

Implement security information and event management (SIEM) solutions to track RADIUS protocol usage and correlate it with known attack patterns.

How to Mitigate CVE-2024-3596

Immediate Actions Required

• Disable reliance on vulnerable MD5 hashing in RADIUS
• Implement stronger hash functions like SHA-256
• Restrict network access to RADIUS servers

Patch Information

As of the last update, no specific patch information is available. Vendors are encouraged to update cryptographic dependencies.

Workarounds

Update RADIUS configurations to use stronger cryptographic methods and consider using more secure protocols like EAP-TLS.

# Configuration example
radiusd -X

# Edit configuration files
disable_md5 = true
use_stronger_hash = sha256