CVE-2024-55025: Weintek Easyweb Auth Bypass Vulnerability

CVE-2024-55025 Overview

CVE-2024-55025 is a broken access control vulnerability affecting the VNC component of Weintek cMT-3072XH2 Human Machine Interface (HMI) systems running easyweb v2.1.53 with OS version 20231011. The vulnerability allows unauthorized attackers to gain access to the HMI system through improper access control mechanisms in the VNC service.

This vulnerability is classified as CWE-284 (Improper Access Control), which occurs when the software fails to properly restrict access to resources or functionality. In industrial control system environments, unauthorized access to HMI systems can have significant operational and safety implications.

Critical Impact

Unauthorized attackers can remotely access the HMI system via the vulnerable VNC component, potentially allowing them to view sensitive operational data and disrupt industrial control processes.

Affected Products

• Weintek cMT-3072XH2 Hardware
• Weintek cMT-3072XH2 Firmware version 20231011
• Weintek Easyweb version 2.1.53

Discovery Timeline

• 2026-03-03 - CVE-2024-55025 published to NVD
• 2026-03-04 - Last updated in NVD database

Technical Details for CVE-2024-55025

Vulnerability Analysis

The vulnerability resides in the VNC (Virtual Network Computing) component of the Weintek cMT-3072XH2 HMI system. The VNC service, which provides remote graphical access to the HMI interface, lacks proper access control mechanisms to authenticate and authorize connecting clients.

In typical HMI deployments, VNC access should be restricted through authentication mechanisms such as passwords or certificate-based authentication. However, in the affected versions, the VNC component permits connections without proper verification of user credentials, enabling any network-accessible attacker to establish a connection.

This represents a significant security risk in industrial environments where HMI systems often control or monitor critical operational technology (OT) processes.

Root Cause

The root cause of this vulnerability is the improper implementation of access control within the VNC component. The affected software fails to enforce authentication requirements or properly validate incoming connection requests before granting access to the HMI system interface.

This type of vulnerability typically arises from:

• Missing authentication enforcement in the VNC service configuration
• Default insecure configurations that allow unauthenticated access
• Lack of proper access control lists (ACLs) to restrict which hosts can connect

Attack Vector

The attack vector for CVE-2024-55025 is network-based. An attacker who has network connectivity to the vulnerable Weintek HMI device can directly connect to the VNC service without providing valid credentials.

The exploitation does not require any prior authentication or special privileges, making it accessible to any attacker who can reach the device over the network. The attack has low complexity and requires no user interaction.

Once connected, an attacker could potentially:

• View real-time operational data displayed on the HMI
• Monitor industrial process states and parameters
• Potentially interact with control elements depending on the system configuration

Technical details regarding the specific exploitation method can be found in the GitHub Gist PoC and the Notion Security Analysis.

Detection Methods for CVE-2024-55025

Indicators of Compromise

• Unexpected VNC connections to Weintek cMT-3072XH2 devices from unauthorized IP addresses
• VNC session logs showing connections without proper authentication sequences
• Unusual network traffic patterns on VNC ports (typically TCP 5900-5999) targeting HMI systems
• Multiple concurrent or rapid VNC connection attempts from external networks

Detection Strategies

• Implement network traffic monitoring to detect unauthorized VNC connection attempts to HMI systems
• Deploy intrusion detection rules to alert on VNC traffic to Weintek devices from untrusted network segments
• Enable and regularly review VNC access logs on affected HMI devices for suspicious connection patterns
• Use network segmentation monitoring to identify any cross-zone VNC traffic that violates security policies

Monitoring Recommendations

• Configure SIEM alerts for VNC protocol traffic originating from non-approved IP ranges targeting OT network segments
• Establish baseline VNC connection patterns and alert on deviations such as connections outside business hours
• Monitor for reconnaissance activities such as port scanning that may precede exploitation attempts
• Implement regular vulnerability scanning of HMI devices to identify systems running affected firmware versions

How to Mitigate CVE-2024-55025

Immediate Actions Required

• Isolate affected Weintek cMT-3072XH2 devices from untrusted networks immediately
• Implement network segmentation to restrict VNC access to authorized management workstations only
• Deploy firewall rules to block VNC traffic from unauthorized sources to affected HMI systems
• Audit all existing VNC connections and terminate any suspicious or unauthorized sessions

Patch Information

At the time of publication, no vendor patch information is available in the CVE data. Organizations should monitor Weintek's official security advisories and support channels for firmware updates that address this vulnerability.

Contact Weintek support directly to inquire about patched firmware versions for the cMT-3072XH2 HMI system that remediate the VNC access control issue.

Workarounds

• Disable the VNC service on affected devices if remote graphical access is not operationally required
• Implement VPN tunneling for all remote HMI access, ensuring VNC traffic never traverses untrusted networks
• Deploy network access control (NAC) solutions to restrict which hosts can communicate with HMI devices
• Use jump hosts or bastion servers as intermediaries for any required VNC access to industrial systems

# Example firewall configuration to restrict VNC access
# Block external VNC access to HMI subnet (adjust IP ranges as needed)
iptables -A FORWARD -p tcp --dport 5900:5999 -d 10.0.100.0/24 -s ! 10.0.50.0/24 -j DROP

# Allow VNC only from authorized management VLAN
iptables -A FORWARD -p tcp --dport 5900:5999 -d 10.0.100.0/24 -s 10.0.50.0/24 -j ACCEPT

# Log blocked VNC connection attempts for monitoring
iptables -A FORWARD -p tcp --dport 5900:5999 -d 10.0.100.0/24 -j LOG --log-prefix "VNC_BLOCKED: "