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#!/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 http://mozilla.org/MPL/2.0/.
# Copyright (c) 2017 Mozilla Corporation
from lib.alerttask import AlertTask
from query_models import SearchQuery, TermMatch, PhraseMatch, TermsMatch
class AlertBruteforceSsh(AlertTask):
def main(self):
self.parse_config('bruteforce_ssh.conf', ['skiphosts'])
search_query = SearchQuery(minutes=2)
search_query.add_must([
PhraseMatch('summary', 'failed'),
TermMatch('details.program', 'sshd'),
TermsMatch('summary', ['login', 'invalid', 'ldap_count_entries', 'publickey'])
])
for ip_address in self.config.skiphosts.split():
search_query.add_must_not(PhraseMatch('summary', ip_address))
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=10)
# 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 = ['ssh']
severity = 'NOTICE'
summary = ('{0} ssh bruteforce attempts by {1}'.format(aggreg['count'], aggreg['value']))
hosts = self.mostCommon(aggreg['allevents'], '_source.details.hostname')
for i in hosts[:5]:
summary += ' {0} ({1} hits)'.format(i[0], i[1])
# Create the alert object based on these properties
return self.createAlertDict(summary, category, tags, aggreg['events'], severity)