CVE-2019-25470: eWON Firmware Auth Bypass Vulnerability

CVE-2019-25470 Overview

CVE-2019-25470 is an authentication bypass vulnerability affecting eWON Firmware versions 12.2 to 13.0. The vulnerability allows attackers with minimal privileges to retrieve sensitive user data by exploiting the wsdReadForm endpoint. Attackers can send POST requests to /wrcgi.bin/wsdReadForm with base64-encoded partial credentials and a crafted wsdList parameter to extract encrypted passwords for all users, which can be decrypted using a hardcoded XOR key.

This vulnerability is classified under CWE-798 (Use of Hard-coded Credentials), highlighting a critical design flaw where sensitive cryptographic keys are embedded directly in the firmware. eWON devices are commonly deployed in industrial environments for remote access and monitoring, making this vulnerability particularly concerning for operational technology (OT) networks.

Critical Impact

Attackers can extract and decrypt all user passwords from vulnerable eWON devices, potentially gaining full administrative access to industrial control systems and remote access gateways.

Affected Products

• eWON Firmware version 12.2
• eWON Firmware version 12.x (12.2 and later)
• eWON Firmware version 13.0

Discovery Timeline

• 2026-03-11 - CVE-2019-25470 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2019-25470

Vulnerability Analysis

The authentication bypass vulnerability exists in the wsdReadForm endpoint, which processes web service requests on eWON devices. The root issue is a combination of insufficient access controls on the endpoint and the use of a hardcoded XOR key for password encryption.

When an attacker sends a specially crafted POST request to /wrcgi.bin/wsdReadForm, the endpoint fails to properly validate the requesting user's authorization level before returning sensitive configuration data. The request includes a base64-encoded credential fragment and a manipulated wsdList parameter that instructs the endpoint to return user account information, including encrypted passwords.

The encryption mechanism uses a static XOR key that is embedded in the firmware. Because this key is hardcoded and consistent across all devices running vulnerable firmware versions, any attacker who extracts or reverse-engineers this key can decrypt all captured passwords. This transforms what might otherwise be a limited information disclosure into a complete credential compromise scenario.

The network-accessible nature of this vulnerability means that any attacker with network access to the eWON device's web interface can exploit it without requiring prior authentication, significantly expanding the attack surface.

Root Cause

The vulnerability stems from two fundamental security design flaws: improper access control on the wsdReadForm endpoint and the use of hardcoded cryptographic material (CWE-798). The endpoint does not properly validate whether the requesting user has sufficient privileges to access user credential data, and the XOR-based encryption provides no meaningful protection since the key is static across all device instances.

Attack Vector

The attack is network-based and requires no prior authentication beyond minimal credentials. An attacker identifies a vulnerable eWON device exposed on the network and sends a POST request to the /wrcgi.bin/wsdReadForm endpoint. The request body contains base64-encoded partial credentials and a wsdList parameter configured to request user account data.

The device responds with encrypted password data for all configured user accounts. The attacker then applies the known hardcoded XOR key to decrypt the passwords offline, obtaining plaintext credentials for all users including administrative accounts. These credentials can be used to gain full control of the device and potentially pivot to other systems in the industrial network.

For technical exploitation details, refer to the Exploit-DB #47380 entry and the VulnCheck Advisory.

Detection Methods for CVE-2019-25470

Indicators of Compromise

• Unexpected POST requests to /wrcgi.bin/wsdReadForm endpoint from external or unauthorized IP addresses
• Multiple rapid requests to the wsdReadForm endpoint, indicating credential enumeration attempts
• Authentication events using credentials from accounts that were not recently accessed by legitimate users
• Web server logs showing base64-encoded payloads with wsdList parameters

Detection Strategies

• Monitor HTTP traffic for POST requests targeting /wrcgi.bin/wsdReadForm with suspicious wsdList parameter values
• Implement network intrusion detection rules to alert on requests to known vulnerable endpoints on eWON devices
• Deploy web application firewall (WAF) rules to block or alert on malformed requests to the vulnerable CGI endpoint
• Review authentication logs for unusual login patterns following potential exploitation windows

Monitoring Recommendations

• Enable comprehensive logging on eWON devices and forward logs to a centralized SIEM for analysis
• Configure alerts for any access to the /wrcgi.bin/wsdReadForm endpoint from non-administrative networks
• Implement network segmentation monitoring to detect lateral movement from compromised eWON devices
• Establish baseline traffic patterns for eWON devices to identify anomalous request volumes

How to Mitigate CVE-2019-25470

Immediate Actions Required

• Identify all eWON devices running firmware versions 12.2 through 13.0 in your environment
• Restrict network access to eWON device web interfaces using firewall rules or VPN requirements
• Rotate all user credentials on potentially affected devices immediately
• Implement network segmentation to isolate eWON devices from general network access

Patch Information

Organizations should consult the eWON official website for the latest firmware updates that address this vulnerability. Upgrading to a firmware version newer than 13.0 that includes fixes for the authentication bypass and hardcoded key issues is the primary remediation.

For additional technical details about the vulnerability, refer to the VulnCheck Advisory: Ewon Firmware Bypass.

Workarounds

• Place eWON devices behind a VPN and require VPN authentication before web interface access
• Implement IP allowlisting to restrict which hosts can communicate with eWON device web interfaces
• Deploy a reverse proxy with authentication in front of eWON devices to add an additional security layer
• Disable remote web interface access if not operationally required, limiting access to local network only

# Example firewall rules to restrict access to eWON devices
# Allow access only from management network
iptables -A INPUT -p tcp --dport 80 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP