MozDef/alerts/write_audit.py

60 строки
2.1 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 http://mozilla.org/MPL/2.0/.
# Copyright (c) 2014 Mozilla Corporation
#
# This code alerts on every successfully opened session on any of the host from a given list
from lib.alerttask import AlertTask
from mozdef_util.query_models import SearchQuery, TermMatch, PhraseMatch
class WriteAudit(AlertTask):
def main(self):
self.parse_config('write_audit.conf', ['skipprocess', 'expectedusers'])
search_query = SearchQuery(minutes=15)
search_query.add_must([
TermMatch('category', 'write'),
TermMatch('details.auditkey', 'audit'),
])
for processname in self.config.skipprocess.split():
search_query.add_must_not(PhraseMatch('details.processname', processname))
self.filtersManual(search_query)
self.searchEventsAggregated('details.originaluser', samplesLimit=10)
self.walkAggregations(threshold=2)
def onAggregation(self, aggreg):
category = 'write'
severity = 'WARNING'
tags = ['audit']
users = set()
paths = set()
for event in aggreg['events']:
users.add(event['_source']['details']['user'])
paths.add(event['_source']['summary'].split(' ')[1])
summary = '{0} Filesystem write(s) to an auditd path ({1}) by {2} ({3})'.format(
aggreg['count'],
', '.join(paths),
', '.join(users),
aggreg['value']
)
if aggreg['value'] in self.config.expectedusers.split(' '):
severity = 'NOTICE'
hostnames = self.mostCommon(aggreg['allevents'], '_source.hostname')
# did they modify more than one host?
# or just modify an existing configuration more than once?
if len(hostnames) > 1:
for i in hostnames[:5]:
summary += ' on {0} ({1} hosts)'.format(i[0], i[1])
return self.createAlertDict(summary, category, tags, aggreg['events'], severity)