'Searches for file upload vulns.
:param freq: A FuzzableRequest'

def audit(self, freq, orig_response):

    if ((freq.get_method().upper() != 'POST') or (not freq.get_file_vars())):
        return
    for file_parameter in freq.get_file_vars():
        for extension in self._extensions:
            (_, file_content, file_name) = get_file_from_template(extension)
            named_stringio = NamedStringIO(file_content, file_name)
            mutants = create_mutants(freq, [named_stringio], fuzzable_param_list=[file_parameter])
            for mutant in mutants:
                mutant.uploaded_file_name = file_name
            self._send_mutants_in_threads(self._uri_opener.send_mutant, mutants, self._analyze_result)
