CVE-2024-12297: Moxa Ethernet Switch Auth Bypass Flaw

CVE-2024-12297 Overview

CVE-2024-12297 is a critical authentication bypass vulnerability affecting Moxa's Ethernet switches. The vulnerability stems from flaws in the device's authorization mechanism, where despite both client-side and back-end server verification being involved in the authentication process, attackers can exploit weaknesses in the implementation. These vulnerabilities may enable brute-force attacks to guess valid credentials or MD5 collision attacks to forge authentication hashes, potentially compromising the security of the device.

Critical Impact

This authentication bypass vulnerability allows remote unauthenticated attackers to gain unauthorized access to Moxa Ethernet switches through brute-force credential guessing or MD5 hash collision attacks, potentially leading to complete device compromise in industrial network environments.

Affected Products

• Moxa EDS-508A Series Ethernet Switches
• Moxa PT Series Switches
• Other Moxa Ethernet switch models as detailed in vendor advisories

Discovery Timeline

• 2025-01-15 - CVE-2024-12297 published to NVD
• 2025-03-06 - Last updated in NVD database

Technical Details for CVE-2024-12297

Vulnerability Analysis

This vulnerability is classified under CWE-656 (Reliance on Security Through Obscurity), indicating that the authentication mechanism relies on implementation details that can be reverse-engineered or bypassed rather than robust cryptographic protections. The core issue lies in the frontend authorization logic, where the client-side and server-side verification can be circumvented through multiple attack vectors.

The authentication process employs MD5 hashing for credential validation, which presents a significant security weakness. MD5 is a cryptographically broken hash algorithm that is susceptible to collision attacks, allowing attackers to generate authentication hashes that match legitimate credentials without knowing the actual password. Furthermore, the implementation appears to lack sufficient protections against automated attacks, enabling brute-force attempts to enumerate valid credentials.

Root Cause

The root cause of this vulnerability is the reliance on a weak authorization mechanism that combines inadequate client-side verification with a backend implementation using the cryptographically deprecated MD5 hash algorithm. The frontend authorization logic disclosure allows attackers to understand the authentication flow and craft attacks that exploit weaknesses in the hash verification process. Additionally, insufficient rate limiting or account lockout mechanisms enable sustained brute-force attacks against the authentication endpoint.

Attack Vector

The vulnerability can be exploited remotely over the network without requiring prior authentication or user interaction. An attacker with network access to the vulnerable Moxa Ethernet switch can target the authentication mechanism through two primary methods:

1. Brute-Force Attack: The attacker systematically attempts credential combinations against the authentication endpoint. Without proper rate limiting or lockout mechanisms, the attacker can iterate through common username/password combinations or targeted password lists until valid credentials are discovered.

2. MD5 Collision Attack: The attacker leverages known weaknesses in the MD5 hash algorithm to generate colliding hashes. By crafting input that produces the same MD5 hash as a legitimate user's credentials, the attacker can forge authentication without knowing the actual password.

The vulnerability mechanism exploits weaknesses in the authorization flow. When authentication requests are processed, the backend server validates the provided credentials using MD5 hashes. Due to the cryptographic weaknesses of MD5 and the exposed frontend logic, attackers can either forge valid hashes through collision attacks or systematically discover credentials through brute-force enumeration. For technical details, refer to Moxa Security Advisory MPSA-241407 and MPSA-241408.

Detection Methods for CVE-2024-12297

Indicators of Compromise

• Unusual spike in authentication attempts to Moxa switch management interfaces from single or distributed sources
• Failed login attempts followed by successful authentication from previously unknown IP addresses
• Unexpected configuration changes on Moxa Ethernet switches after authentication events
• Network logs showing repeated requests to authentication endpoints with varying credential payloads

Detection Strategies

• Implement network monitoring rules to detect high-frequency authentication attempts against Moxa switch management interfaces
• Deploy intrusion detection signatures that identify MD5 collision attack patterns or abnormal authentication traffic
• Monitor and alert on successful logins from unexpected geographic locations or IP ranges
• Review authentication logs for patterns consistent with automated brute-force tools

Monitoring Recommendations

• Enable comprehensive logging on all Moxa Ethernet switches and forward logs to a centralized SIEM solution
• Establish baseline authentication patterns and configure anomaly detection for deviations
• Implement network segmentation monitoring to detect lateral movement following potential switch compromise
• Configure alerts for configuration changes or firmware modifications on industrial network devices

How to Mitigate CVE-2024-12297

Immediate Actions Required

• Review Moxa security advisories MPSA-241407 and MPSA-241408 for affected product versions and available patches
• Restrict network access to Moxa switch management interfaces to trusted administrative networks only
• Implement strong, unique passwords for all device accounts and change default credentials immediately
• Enable available account lockout policies if supported by the device firmware

Patch Information

Moxa has released security advisories addressing this vulnerability for affected product lines. Administrators should consult MPSA-241407 for EDS-508A Series and MPSA-241408 for PT Series switches to obtain specific firmware updates and patching instructions for their deployments.

Workarounds

• Isolate Moxa Ethernet switches on dedicated management VLANs with strict access control lists limiting connections to authorized administrator workstations
• Deploy a network firewall or access control mechanism in front of switch management interfaces to block unauthorized access and rate-limit authentication attempts
• Consider implementing VPN or jump host requirements for administrative access to critical industrial network infrastructure
• Disable web-based management interfaces if not required and use alternative management methods with stronger authentication

# Example ACL configuration to restrict management access (adapt to your environment)
# On upstream router/firewall - allow only trusted admin subnet
iptables -A INPUT -p tcp --dport 80 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP