CVE-2024-42001: Vonets VAR1200-H Auth Bypass Vulnerability

CVE-2024-42001 Overview

CVE-2024-42001 is an improper authentication vulnerability (CWE-425) affecting Vonets industrial WiFi bridge relays and WiFi bridge repeaters running firmware versions 3.3.23.6.9 and prior. This authentication bypass flaw enables an unauthenticated remote attacker to bypass authentication mechanisms via a specially crafted direct request when another user has an active session on the device.

This vulnerability is particularly concerning for industrial control system (ICS) environments where Vonets devices are commonly deployed to provide WiFi connectivity for industrial equipment. Successful exploitation could allow attackers to gain unauthorized administrative access to network infrastructure devices.

Critical Impact

Unauthenticated remote attackers can bypass authentication and gain unauthorized access to industrial WiFi bridge devices when a legitimate user session is active, potentially compromising industrial network infrastructure.

Affected Products

• Vonets VAR1200-H and VAR1200-L (firmware versions ≤ 3.3.23.6.9)
• Vonets VAR600-H and VAR11N-300 (firmware versions ≤ 3.3.23.6.9)
• Vonets VAP11AC, VAP11S, VAP11S-5G (firmware versions ≤ 3.3.23.6.9)
• Vonets VAP11G, VAP11G-300, VAP11G-500, VAP11G-500S (firmware versions ≤ 3.3.23.6.9)
• Vonets VAP11N-300, VBG1200, VGA-1000 (firmware versions ≤ 3.3.23.6.9)

Discovery Timeline

• August 12, 2024 - CVE-2024-42001 published to NVD
• August 20, 2024 - Last updated in NVD database

Technical Details for CVE-2024-42001

Vulnerability Analysis

The vulnerability stems from improper authentication handling in the Vonets firmware web management interface. The device fails to properly validate authentication credentials when processing direct requests to administrative endpoints while another user maintains an active session. This is classified as CWE-425 (Direct Request or "Forced Browsing"), where the application does not adequately enforce access restrictions.

The attack requires that a legitimate administrator has an active session on the target device. When this condition is met, an attacker can craft specific HTTP requests to directly access protected administrative functions without providing valid credentials. This session-riding behavior indicates a fundamental flaw in how the device manages authentication state and request authorization.

Industrial WiFi bridges are often deployed in critical infrastructure environments to connect legacy industrial equipment to modern networks. The network-accessible nature of this vulnerability, combined with the device's role in industrial settings, creates significant risk for organizations relying on these devices.

Root Cause

The root cause is improper authentication enforcement in the Vonets firmware's web management interface. The application fails to independently verify authentication credentials for each incoming request, instead relying on the existence of an active session without properly binding that session to the requesting client. This allows attackers to piggyback on legitimate administrator sessions.

Attack Vector

The attack is conducted remotely over the network. An attacker must have network access to the device's web management interface and timing alignment with an active legitimate user session. The attacker crafts direct HTTP requests to administrative endpoints that normally require authentication. Because the device improperly associates the existing legitimate session with the unauthenticated request, the attacker gains access to protected functionality.

The vulnerability exploitation flow involves:

1. Attacker identifies a target Vonets device on the network
2. Attacker waits for or confirms a legitimate administrator session is active
3. Attacker sends crafted direct requests to protected administrative endpoints
4. Device processes requests without proper authentication validation
5. Attacker gains unauthorized administrative access

Detection Methods for CVE-2024-42001

Indicators of Compromise

• Unexpected administrative configuration changes on Vonets devices during periods of legitimate administrator inactivity
• Multiple concurrent sessions or anomalous session patterns in device logs
• Unauthorized access attempts to web management interfaces from unexpected IP addresses
• Configuration modifications that don't correlate with authorized change windows

Detection Strategies

• Monitor network traffic for anomalous HTTP requests to Vonets device management interfaces, especially from non-administrative IP addresses
• Implement network segmentation monitoring to detect unauthorized access attempts to industrial network segments
• Deploy intrusion detection rules to identify direct request patterns targeting common administrative endpoints on Vonets devices
• Review device logs for authentication anomalies and session management irregularities

Monitoring Recommendations

• Enable logging on Vonets devices and forward logs to a central SIEM for correlation and analysis
• Implement network-level monitoring for all traffic to and from industrial WiFi bridge devices
• Establish baseline behavioral patterns for administrative access and alert on deviations
• Configure alerts for any access attempts originating from outside authorized management networks

How to Mitigate CVE-2024-42001

Immediate Actions Required

• Review the CISA ICS Advisory ICSA-24-214-08 for vendor-specific guidance and updates
• Isolate affected Vonets devices from untrusted networks and implement strict network segmentation
• Restrict web management interface access to authorized IP addresses only using firewall rules
• Minimize the number of active administrative sessions and implement session timeout policies
• Monitor for unauthorized access attempts and configuration changes on all affected devices

Patch Information

Organizations should consult the CISA ICS Advisory ICSA-24-214-08 for the latest information on available firmware updates from Vonets. Given the nature of this vulnerability, applying vendor-provided firmware updates is the primary remediation path when available.

Workarounds

• Implement network segmentation to isolate Vonets devices from general network access
• Use VPN or jump hosts for administrative access, limiting direct network exposure of management interfaces
• Configure host-based firewall rules to restrict management interface access to specific authorized IP addresses
• Implement strict session management policies including automatic timeout and single-session enforcement where possible
• Consider deploying network access control (NAC) solutions to limit which devices can communicate with industrial WiFi bridges

# Example firewall rule to restrict management access (iptables)
# Replace VONETS_IP with device IP and ADMIN_IP with authorized management station
iptables -A INPUT -d VONETS_IP -p tcp --dport 80 -s ADMIN_IP -j ACCEPT
iptables -A INPUT -d VONETS_IP -p tcp --dport 443 -s ADMIN_IP -j ACCEPT
iptables -A INPUT -d VONETS_IP -p tcp --dport 80 -j DROP
iptables -A INPUT -d VONETS_IP -p tcp --dport 443 -j DROP