'Try to define the cut with a very strict algorithm based on the
/etc/passwd file format.
:return : True if vuln can be exploited and the information extracted'

def _strict_with_etc_passwd(self, vuln_obj):

    if (not ('passwd' in vuln_obj.get_mutant().get_token_value())):
        return False
    mutant = vuln_obj.get_mutant()
    try:
        response_a = self._uri_opener.send_mutant(mutant)
        response_b = self._uri_opener.send_mutant(mutant)
    except BaseFrameworkException as e:
        om.out.error(str(e))
        return False
    try:
        cut = self._define_cut_from_etc_passwd(response_a.get_body(), response_b.get_body())
    except ValueError as ve:
        om.out.error(str(ve))
        return False
    else:
        return cut
