':return: True if the vulnerability can be exploited.'

def _verify_vuln(self, vuln):

    is_error_resp = self._configure_is_error_function(vuln, 5)
    delimiter = self._get_delimiter(vuln, is_error_resp)
    self.STR_DELIM = delimiter
    orig_value = vuln.get_mutant().get_token_original_value()
    self.TRUE_COND = ('%s%s    and    %s%i%s=%s%i' % (orig_value, self.STR_DELIM, self.STR_DELIM, self.rnum, self.STR_DELIM, self.STR_DELIM, self.rnum))
    self.FALSE_COND = ('%s%s    and    %s%i%s=%s%i' % (orig_value, self.STR_DELIM, self.STR_DELIM, self.rnum, self.STR_DELIM, self.STR_DELIM, (self.rnum + 1)))
    mutant = vuln.get_mutant()
    mutant_false = mutant.copy()
    mutant_false.set_token_value(self.FALSE_COND)
    mutant_true = mutant.copy()
    mutant_true.set_token_value(self.TRUE_COND)
    try:
        false_resp = self._uri_opener.send_mutant(mutant_false)
        true_resp = self._uri_opener.send_mutant(mutant_true)
    except BaseFrameworkException as e:
        return ('Error    "%s".' % e)
    else:
        if (is_error_resp(false_resp.get_body()) and (not is_error_resp(true_resp.get_body()))):
            return (True, is_error_resp)
    return (False, None)
