CVE-2025-65011

Executive Summary

CVE-2025-65011 is a critical information disclosure vulnerability affecting the WODESYS WD-R608U router (also known as WDR122B V2.0 and WDR28). An unauthenticated attacker can directly access sensitive configuration files by referencing their known paths, bypassing any authentication or authorization controls. The vulnerability stems from a lack of proper access control (CWE-425) on the router's web interface. The vendor was notified but did not provide a patch or version range; only firmware version WDR28081123OV1.01 has been confirmed vulnerable. This issue poses a high risk to network integrity as exposed configuration files may contain credentials, network topology, and other sensitive data.

Supply Chain & Package Security

This vulnerability is not related to any open-source package ecosystem (NPM, PyPI, Go, Ruby). It affects a proprietary embedded device firmware. The supply chain risk is limited to the device's manufacturing and distribution channels; no package registry is involved.

CVSS Breakdown & Threat Level

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Base Score: 7.5 (High)
Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality Impact: High
Integrity Impact: None
Availability Impact: None

Threat Level: High. The vulnerability is trivial to exploit and requires no authentication. An attacker can silently harvest sensitive configuration data, which may lead to further compromise of the network.

Deep Dive & Mechanics

The WD-R608U router exposes its web management interface on port 80 (HTTP). The vulnerability lies in the lack of access control for static configuration files. By directly requesting a known file path (e.g., /config.cfg, /backup.cfg, /etc/passwd), an unauthenticated user can retrieve the file contents. The router does not check for a valid session or authentication token before serving these files.

The root cause is a missing authorization check in the web server's file-serving logic. The server likely uses a simple file-based routing mechanism that does not differentiate between public and protected resources. This is a classic example of CWE-425: Direct Request ('Forced Browsing').

Attack Flow:

1. Attacker identifies a vulnerable WD-R608U router via Shodan or other scanning.
2. Attacker sends an HTTP GET request to a known configuration file path, e.g., http://<router-ip>/config.cfg.
3. The router responds with the file contents without any authentication challenge.
4. Attacker extracts sensitive data (e.g., admin credentials, Wi-Fi keys, VPN settings).

Vulnerable vs. Patched Code

No patched code is available. The vulnerable firmware (WDR28081123OV1.01) lacks any access control for configuration files. A hypothetical patch would involve implementing a session-based authentication check before serving any file from the /config/ or /backup/ directories.

Vulnerable (pseudo-code):

# No authentication check
def handle_request(path):
    if path.startswith("/config/"):
        return read_file(path)
    else:
        return 404

Patched (pseudo-code):

def handle_request(path):
    if path.startswith("/config/"):
        if not is_authenticated(session):
            return 401
        return read_file(path)
    else:
        return 404

Exploitation & Lab Setup

Red Team

Prerequisites:

• A vulnerable WD-R608U router (firmware WDR28081123OV1.01) or a lab environment with the firmware emulated.
• Network access to the router's web interface (port 80).

Exploitation Steps:

1. Identify the target router's IP address (e.g., via Shodan or local network scan).
2. Use curl or a web browser to request configuration files:

   curl http://<router-ip>/config.cfg
   curl http://<router-ip>/backup.cfg
   curl http://<router-ip>/etc/passwd
   

3. Analyze the retrieved files for credentials, keys, and network information.

Example Output:

admin:admin123
wifi_ssid:HomeNetwork
wifi_key:SecretKey123

Blue Team

Detection:

• Monitor HTTP access logs for requests to /config.cfg, /backup.cfg, /etc/passwd, or similar paths.
• Alert on any unauthenticated requests to these paths from external IPs.

Hunting:

• Search for devices with open port 80 and HTTP title "WD-R608U" or "WODESYS".
• Check for anomalous traffic patterns, such as repeated GET requests to configuration files.

Mitigation:

• Isolate the router from untrusted networks (e.g., place behind a firewall).
• If possible, disable remote management or restrict access to trusted IPs.
• Monitor for firmware updates from the vendor (unlikely).

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP GET requests to paths: /config.cfg, /backup.cfg, /etc/passwd, /etc/shadow, /www/config.cfg
• Source IPs scanning for these paths (e.g., from Shodan crawlers or attackers).

Host IOCs:

• Unauthorized access logs showing retrieval of configuration files.
• Presence of downloaded configuration files on an attacker's machine.

File IOCs:

• Configuration files containing plaintext credentials (e.g., admin:admin123).
• Backup files with .cfg extension.

Detection Engineering

YARA Rule

rule CVE_2025_65011_WODESYS_Config_Exposure {
    meta:
        description = "Detects HTTP responses containing WODESYS router configuration data"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-65011"
    strings:
        $s1 = "admin:" ascii wide nocase
        $s2 = "wifi_ssid" ascii wide nocase
        $s3 = "wifi_key" ascii wide nocase
        $s4 = "WDR28081123OV1.01" ascii wide nocase
    condition:
        any of ($s*) and filesize < 1MB
}

Sigma Rule

title: CVE-2025-65011 WODESYS Router Config File Access
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated access to WODESYS router configuration files
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-65011
logsource:
    category: webserver
    product: apache
    service: http
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem:
            - '/config.cfg'
            - '/backup.cfg'
            - '/etc/passwd'
            - '/etc/shadow'
    condition: selection
falsepositives:
    - Legitimate administrative access from trusted IPs
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-65011 WODESYS Router Config File Access"; flow:to_server; content:"GET"; http_method; content:"/config.cfg"; http_uri; nocase; sid:1000001; rev:1;)
alert http any any -> any any (msg:"CVE-2025-65011 WODESYS Router Config File Access"; flow:to_server; content:"GET"; http_method; content:"/backup.cfg"; http_uri; nocase; sid:1000002; rev:1;)
alert http any any -> any any (msg:"CVE-2025-65011 WODESYS Router Config File Access"; flow:to_server; content:"GET"; http_method; content:"/etc/passwd"; http_uri; nocase; sid:1000003; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the device: Place the router behind a firewall that restricts access to the web interface (port 80) to only trusted internal IPs.
2. Disable remote management: If the router allows, disable WAN-side access to the admin interface.
3. Change default credentials: Immediately change all default passwords (admin, Wi-Fi, etc.) if they were exposed.

Long-term Solutions:

• Firmware update: Monitor the vendor's website for a patched firmware. If none is available, consider replacing the device with a more secure alternative.
• Network segmentation: Place the router in a separate VLAN with strict access controls.
• Vendor communication: Continue to pressure the vendor for a fix; consider reporting to CERT/CC if unresponsive.

Workarounds:

• Use a reverse proxy with authentication (e.g., nginx with basic auth) in front of the router's web interface.
• Implement network-based IPS rules (e.g., Suricata) to block requests to known configuration paths.

Valters IT
DevSecOps & Cyber Threat Intelligence