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Changes to extract EVTX TimeCreated log2timeline#442
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joachimmetz committed Jun 17, 2019
1 parent 839b843 commit 659ea9c
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Showing 2 changed files with 73 additions and 19 deletions.
82 changes: 68 additions & 14 deletions plaso/parsers/winevtx.py
Original file line number Diff line number Diff line change
Expand Up @@ -4,11 +4,13 @@
from __future__ import unicode_literals

from collections import namedtuple
from xml.etree import ElementTree

import pyevtx

from dfdatetime import filetime as dfdatetime_filetime
from dfdatetime import semantic_time as dfdatetime_semantic_time
from dfdatetime import time_elements as dfdatetime_time_elements

from plaso.containers import events
from plaso.containers import time_events
Expand Down Expand Up @@ -61,17 +63,6 @@ class WinEvtxParser(interface.FileObjectParser):
NAME = 'winevtx'
DESCRIPTION = 'Parser for Windows XML EventLog (EVTX) files.'

@classmethod
def GetFormatSpecification(cls):
"""Retrieves the format specification.
Returns:
FormatSpecification: format specification.
"""
format_specification = specification.FormatSpecification(cls.NAME)
format_specification.AddNewSignature(b'ElfFile\x00', offset=0)
return format_specification

# Mapping from evtx_record.strings entries to meaningful names.
# This mapping is different for each event_identifier.
# TODO: make this more generic in context of #158.
Expand All @@ -96,7 +87,41 @@ def GetFormatSpecification(cls):
]
}

def _GetEventData(
def _GetCreationTimeFromXMLString(
self, parser_mediator, record_index, xml_string):
"""Retrieves the creationg time from the XML string.
Args:
parser_mediator (ParserMediator): mediates interactions between parsers
and other components, such as storage and dfvfs.
record_index (int): event record index.
xml_string (str): event XML string.
Returns:
str: creation date and time formatted as ISO 8601 or None if not
available.
"""
xml_root = ElementTree.fromstring(xml_string)

system_xml_element = xml_root.find(
'{http://schemas.microsoft.com/win/2004/08/events/event}System')
if system_xml_element is None:
parser_mediator.ProduceExtractionWarning(
'missing System XML element in event record: {0:d}'.format(
record_index))
return None

time_created_xml_element = system_xml_element.find(
'{http://schemas.microsoft.com/win/2004/08/events/event}TimeCreated')
if time_created_xml_element is None:
parser_mediator.ProduceExtractionWarning(
'missing TimeCreated XML element in event record: {0:d}'.format(
record_index))
return None

return time_created_xml_element.get('SystemTime')

def _GetEventDataFromRecord(
self, parser_mediator, record_index, evtx_record, recovered=False):
"""Extract data from a Windows XML EventLog (EVTX) record.
Expand Down Expand Up @@ -184,7 +209,7 @@ def _ParseRecord(
evtx_record (pyevtx.record): event record.
recovered (Optional[bool]): True if the record was recovered.
"""
event_data = self._GetEventData(
event_data = self._GetEventDataFromRecord(
parser_mediator, record_index, evtx_record, recovered=recovered)

try:
Expand All @@ -196,7 +221,7 @@ def _ParseRecord(

written_time = None

if not written_time:
if written_time is None:
date_time = dfdatetime_semantic_time.SemanticTime('Not set')
else:
date_time = dfdatetime_filetime.Filetime(timestamp=written_time)
Expand All @@ -205,6 +230,24 @@ def _ParseRecord(
date_time, definitions.TIME_DESCRIPTION_WRITTEN)
parser_mediator.ProduceEventWithEventData(event, event_data)

creation_time_string = self._GetCreationTimeFromXMLString(
parser_mediator, record_index, event_data.xml_string)
if creation_time_string:
date_time = dfdatetime_time_elements.TimeElementsInMicroseconds()

try:
date_time.CopyFromStringISO8601(creation_time_string)
except ValueError as exception:
parser_mediator.ProduceExtractionWarning(
'unsupported creation time: {0:s} with error: {1!s}.'.format(
creation_time_string, exception))
date_time = None

if date_time:
event = time_events.DateTimeValuesEvent(
date_time, definitions.TIME_DESCRIPTION_CREATION)
parser_mediator.ProduceEventWithEventData(event, event_data)

def _ParseRecords(self, parser_mediator, evtx_file):
"""Parses Windows XML EventLog (EVTX) records.
Expand Down Expand Up @@ -245,6 +288,17 @@ def _ParseRecords(self, parser_mediator, evtx_file):
'unable to parse recovered event record: {0:d} with error: '
'{1!s}').format(record_index, exception))

@classmethod
def GetFormatSpecification(cls):
"""Retrieves the format specification.
Returns:
FormatSpecification: format specification.
"""
format_specification = specification.FormatSpecification(cls.NAME)
format_specification.AddNewSignature(b'ElfFile\x00', offset=0)
return format_specification

def ParseFileObject(self, parser_mediator, file_object):
"""Parses a Windows XML EventLog (EVTX) file-like object.
Expand Down
10 changes: 5 additions & 5 deletions tests/parsers/winevtx.py
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@ def testParse(self):
# Number of recovered records : 0
# Log type : System

self.assertEqual(storage_writer.number_of_events, 1601)
self.assertEqual(storage_writer.number_of_events, 3202)

events = list(storage_writer.GetEvents())

Expand Down Expand Up @@ -62,7 +62,7 @@ def testParse(self):

self.assertEqual(event.strings[1], expected_string)

event = events[1]
event = events[2]

self.CheckTimestamp(event.timestamp, '2012-03-14 04:17:38.276340')
self.assertEqual(
Expand Down Expand Up @@ -127,11 +127,11 @@ def testParseTruncated(self):
storage_writer = self._ParseFile(['System2.evtx'], parser)

self.assertEqual(storage_writer.number_of_warnings, 0)
self.assertEqual(storage_writer.number_of_events, 194)
self.assertEqual(storage_writer.number_of_events, 388)

events = list(storage_writer.GetEvents())

event = events[178]
event = events[356]

expected_strings_parsed = [
('source_user_id', 'S-1-5-18'),
Expand All @@ -146,7 +146,7 @@ def testParseTruncated(self):

self.assertEqual(event.event_identifier, 4624)

event = events[180]
event = events[360]

expected_strings_parsed = [
('source_user_id', 'S-1-5-21-1539974973-2753941131-3212641383-1000'),
Expand Down

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