MozDef/alerts/guard_duty_probe.py

44 строки
1.7 KiB
Python

#!/usr/bin/env python
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at https://mozilla.org/MPL/2.0/.
# Copyright (c) 2014 Mozilla Corporation
from lib.alerttask import AlertTask
from mozdef_util.query_models import SearchQuery, TermMatch, ExistsMatch
class AlertGuardDutyProbe(AlertTask):
def main(self):
# Create a query to look back the last 20 minutes
search_query = SearchQuery(minutes=20)
# Add search terms to our query
search_query.add_must([
TermMatch('source', 'guardduty'),
TermMatch('details.finding.action.actionType', 'PORT_PROBE'),
ExistsMatch('details.sourceipaddress'),
])
self.filtersManual(search_query)
# Search aggregations on field 'sourceipaddress'
# keep X samples of events at most
self.searchEventsAggregated('details.sourceipaddress', samplesLimit=10)
# alert when >= X matching events in an aggregation
self.walkAggregations(threshold=1)
# Set alert properties
def onAggregation(self, aggreg):
# aggreg['count']: number of items in the aggregation, ex: number of failed login attempts
# aggreg['value']: value of the aggregation field, ex: toto@example.com
# aggreg['events']: list of events in the aggregation
category = 'bruteforce'
tags = ['guardduty', 'bruteforce']
severity = 'INFO'
summary = "Guard Duty Port Probe by {}".format(aggreg['value'])
# Create the alert object based on these properties
return self.createAlertDict(summary, category, tags, aggreg['events'], severity)