@staticmethod
def _read_fs_register_x64(concrete_target):
    """
        Injects a small shellcode to leak the fs segment register address. In Linux x64 this address is pointed by fs[0]
        :param concrete_target: ConcreteTarget which will be used to get the fs register address
        :return: fs register address
        :rtype string
        """
    exfiltration_reg = 'rax'
    read_fs0_x64 = b'dH\x8b\x04%\x00\x00\x00\x00\x90\x90\x90\x90'
    return concrete_target.execute_shellcode(read_fs0_x64, exfiltration_reg)
