Source code for plaso.parsers.mac_appfirewall

# -*- coding: utf-8 -*-
"""This file contains a appfirewall.log (MacOS Firewall) parser."""

from __future__ import unicode_literals

import pyparsing

from dfdatetime import time_elements as dfdatetime_time_elements

from plaso.containers import events
from plaso.containers import time_events
from plaso.lib import errors
from plaso.lib import definitions
from plaso.lib import timelib
from plaso.parsers import logger
from plaso.parsers import manager
from plaso.parsers import text_parser


[docs]class MacAppFirewallLogEventData(events.EventData): """MacOS Firewall log event data. Attributes: action (str): action. agent (str): agent that save the log. computer_name (str): name of the computer. process_name (str): name of the entity that tried do the action. status (str): saved status action. """ DATA_TYPE = 'mac:appfirewall:line' def __init__(self): """Initializes event data.""" super(MacAppFirewallLogEventData, self).__init__(data_type=self.DATA_TYPE) self.action = None self.agent = None self.computer_name = None self.process_name = None
self.status = None
[docs]class MacAppFirewallParser(text_parser.PyparsingSingleLineTextParser): """Parse text based on appfirewall.log file.""" NAME = 'mac_appfirewall_log' DESCRIPTION = 'Parser for appfirewall.log files.' _ENCODING = 'utf-8' # Define how a log line should look like. # Example: 'Nov 2 04:07:35 DarkTemplar-2.local socketfilterfw[112] ' # '<Info>: Dropbox: Allow (in:0 out:2)' # INFO: process_name is going to have a white space at the beginning. DATE_TIME = pyparsing.Group( text_parser.PyparsingConstants.THREE_LETTERS.setResultsName('month') + text_parser.PyparsingConstants.ONE_OR_TWO_DIGITS.setResultsName('day') + text_parser.PyparsingConstants.TIME_ELEMENTS) FIREWALL_LINE = ( DATE_TIME.setResultsName('date_time') + pyparsing.Word(pyparsing.printables).setResultsName('computer_name') + pyparsing.Word(pyparsing.printables).setResultsName('agent') + pyparsing.Literal('<').suppress() + pyparsing.CharsNotIn('>').setResultsName('status') + pyparsing.Literal('>:').suppress() + pyparsing.CharsNotIn(':').setResultsName('process_name') + pyparsing.Literal(':') + pyparsing.SkipTo(pyparsing.lineEnd).setResultsName('action')) # Repeated line. # Example: Nov 29 22:18:29 --- last message repeated 1 time --- REPEATED_LINE = ( DATE_TIME.setResultsName('date_time') + pyparsing.Literal('---').suppress() + pyparsing.CharsNotIn('---').setResultsName('process_name') + pyparsing.Literal('---').suppress()) LINE_STRUCTURES = [ ('logline', FIREWALL_LINE), ('repeated', REPEATED_LINE)] def __init__(self): """Initializes a parser object.""" super(MacAppFirewallParser, self).__init__() self._last_month = 0 self._previous_structure = None self._year_use = 0 def _GetTimeElementsTuple(self, structure): """Retrieves a time elements tuple from the structure. Args: structure (pyparsing.ParseResults): structure of tokens derived from a line of a text file. Returns: tuple: containing: year (int): year. month (int): month, where 1 represents January. day_of_month (int): day of month, where 1 is the first day of the month. hours (int): hours. minutes (int): minutes. seconds (int): seconds. """ month, day, hours, minutes, seconds = structure.date_time # Note that dfdatetime_time_elements.TimeElements will raise ValueError # for an invalid month. month = timelib.MONTH_DICT.get(month.lower(), 0) if month != 0 and month < self._last_month: # Gap detected between years. self._year_use += 1 return (self._year_use, month, day, hours, minutes, seconds) def _ParseLogLine(self, parser_mediator, structure, key): """Parse a single log line and produce an event object. Args: parser_mediator (ParserMediator): mediates interactions between parsers and other components, such as storage and dfvfs. key (str): identifier of the structure of tokens. structure (pyparsing.ParseResults): structure of tokens derived from a line of a text file. """ time_elements_tuple = self._GetTimeElementsTuple(structure) try: date_time = dfdatetime_time_elements.TimeElements( time_elements_tuple=time_elements_tuple) except ValueError: parser_mediator.ProduceExtractionWarning( 'invalid date time value: {0!s}'.format(structure.date_time)) return self._last_month = time_elements_tuple[1] # If the actual entry is a repeated entry, we take the basic information # from the previous entry, but use the timestamp from the actual entry. if key == 'logline': self._previous_structure = structure else: structure = self._previous_structure event_data = MacAppFirewallLogEventData() event_data.action = structure.action event_data.agent = structure.agent event_data.computer_name = structure.computer_name # Due to the use of CharsNotIn pyparsing structure contains whitespaces # that need to be removed. event_data.process_name = structure.process_name.strip() event_data.status = structure.status event = time_events.DateTimeValuesEvent( date_time, definitions.TIME_DESCRIPTION_ADDED) parser_mediator.ProduceEventWithEventData(event, event_data)
[docs] def ParseRecord(self, parser_mediator, key, structure): """Parses a log record structure and produces events. Args: parser_mediator (ParserMediator): mediates interactions between parsers and other components, such as storage and dfvfs. key (str): identifier of the structure of tokens. structure (pyparsing.ParseResults): structure of tokens derived from a line of a text file. Raises: ParseError: when the structure type is unknown. """ if key not in ('logline', 'repeated'): raise errors.ParseError( 'Unable to parse record, unknown structure: {0:s}'.format(key))
self._ParseLogLine(parser_mediator, structure, key)
[docs] def VerifyStructure(self, parser_mediator, line): """Verify that this file is a Mac AppFirewall log file. Args: parser_mediator (ParserMediator): mediates interactions between parsers and other components, such as storage and dfvfs. line (str): line from a text file. Returns: bool: True if the line is in the expected format, False if not. """ self._last_month = 0 self._year_use = parser_mediator.GetEstimatedYear() try: structure = self.FIREWALL_LINE.parseString(line) except pyparsing.ParseException as exception: logger.debug(( 'Unable to parse file as a Mac AppFirewall log file with error: ' '{0!s}').format(exception)) return False if structure.action != 'creating /var/log/appfirewall.log': logger.debug( 'Not a Mac AppFirewall log file, invalid action: {0!s}'.format( structure.action)) return False if structure.status != 'Error': logger.debug( 'Not a Mac AppFirewall log file, invalid status: {0!s}'.format( structure.status)) return False time_elements_tuple = self._GetTimeElementsTuple(structure) try: dfdatetime_time_elements.TimeElements( time_elements_tuple=time_elements_tuple) except ValueError: logger.debug(( 'Not a Mac AppFirewall log file, invalid date and time: ' '{0!s}').format(structure.date_time)) return False self._last_month = time_elements_tuple[1]
return True manager.ParsersManager.RegisterParser(MacAppFirewallParser)