CVE-2020-37097: Edimax EW-7438RPn Info Disclosure Flaw

CVE-2020-37097 Overview

CVE-2020-37097 is an information disclosure vulnerability affecting the Edimax EW-7438RPn Mini WiFi range extender running firmware version 1.13. The vulnerability exists in the wlencrypt_wiz.asp file, which exposes sensitive WiFi network configuration details including the network name (SSID) and plaintext password stored in device configuration variables. This flaw allows unauthenticated remote attackers to retrieve WiFi credentials by simply accessing the vulnerable script through a web browser.

Critical Impact

Attackers can remotely extract WiFi network credentials including the SSID and plaintext password without authentication, potentially compromising the entire wireless network and enabling further attacks on connected devices.

Affected Products

• Edimax EW-7438RPn Mini firmware version 1.13
• Edimax N300 WiFi Range Extender series (potentially affected)

Discovery Timeline

• 2026-02-03 - CVE CVE-2020-37097 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2020-37097

Vulnerability Analysis

This vulnerability is classified under CWE-522 (Insufficiently Protected Credentials), which describes scenarios where credentials are stored, transmitted, or otherwise handled in an insecure manner. In this case, the Edimax EW-7438RPn range extender stores WiFi network credentials in plaintext within device configuration variables that are directly accessible through the wlencrypt_wiz.asp web interface file.

The flaw represents a fundamental security design issue where sensitive network credentials are exposed without requiring any form of authentication. An attacker with network access to the device's web interface can simply request the vulnerable ASP file and parse the response to extract the WiFi network name and password in cleartext.

Root Cause

The root cause of this vulnerability stems from insecure credential storage and lack of access control on the wlencrypt_wiz.asp configuration file. The device stores WiFi credentials in plaintext within configuration variables that are rendered directly in the ASP page output. Additionally, there is no authentication or authorization check performed before serving this sensitive configuration data, allowing any network-accessible user to retrieve the credentials.

Attack Vector

The attack vector is network-based and requires no user interaction or prior authentication. An attacker on the same network segment as the Edimax device can access the vulnerable wlencrypt_wiz.asp endpoint through a standard HTTP request. The device responds with the configuration page containing the WiFi SSID and password in plaintext embedded in JavaScript variables or HTML content.

The attack can be executed by:

1. Identifying the Edimax range extender on the local network
2. Accessing the device's web interface (typically at http://192.168.2.2 or similar)
3. Requesting the wlencrypt_wiz.asp file directly
4. Parsing the response to extract the plaintext WiFi credentials

For detailed technical information and proof-of-concept details, refer to the Exploit-DB entry #48365 and the VulnCheck Advisory.

Detection Methods for CVE-2020-37097

Indicators of Compromise

• Unusual HTTP requests to wlencrypt_wiz.asp on Edimax range extender devices
• Multiple access attempts to the device's web interface from unexpected IP addresses
• Network scanning activity targeting common Edimax default IP ranges
• Unauthorized devices connecting to the WiFi network using previously secure credentials

Detection Strategies

• Monitor network traffic for HTTP requests containing wlencrypt_wiz.asp in the URI path
• Implement network segmentation to isolate IoT devices and range extenders from critical network assets
• Deploy intrusion detection rules to alert on access attempts to known vulnerable Edimax endpoints
• Conduct regular network audits to identify Edimax EW-7438RPn devices running vulnerable firmware

Monitoring Recommendations

• Configure logging on network edge devices to capture all traffic to and from Edimax range extenders
• Implement alerting for new device associations on the WiFi network that may indicate credential theft
• Regularly review connected device lists for unauthorized or unknown clients
• Monitor for changes in WiFi network configuration that may indicate compromise

How to Mitigate CVE-2020-37097

Immediate Actions Required

• Check if any Edimax EW-7438RPn devices are present on your network and identify their firmware versions
• Restrict network access to the device's web management interface using firewall rules or network segmentation
• Change WiFi network credentials immediately if exposure is suspected
• Consider replacing vulnerable devices with models from vendors that provide regular security updates

Patch Information

At the time of this analysis, no official patch information is available from Edimax for this vulnerability. Users should check the Edimax Product Page for any firmware updates that may address this issue. If no patch is available, consider implementing the workarounds below or replacing the affected device.

Workarounds

• Implement network access control lists (ACLs) to restrict access to the range extender's web interface to trusted management stations only
• Place the Edimax device on an isolated network segment or VLAN to limit exposure
• Disable remote management if the feature is available and not required
• Use a VPN or other secure tunnel when accessing the device for management purposes
• Monitor network logs for suspicious access attempts to the vulnerable endpoint

# Example iptables rule to restrict access to Edimax web interface
# Replace 192.168.2.2 with your device IP and 192.168.1.100 with trusted management IP
iptables -A FORWARD -d 192.168.2.2 -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A FORWARD -d 192.168.2.2 -p tcp --dport 80 -j DROP