etl-parser

Event Trace Log file reader in pure Python

etl-parser is a pure Python 3 parser library for ETL Windows log files. ETL is the default format for ETW as well as the default format for the Kernel logger.

etl-parser has no system dependencies and will work well on both Windows and Linux.

Since this format is not documented, we merged information from the blog of Geoff Chappel and reverse engineering activities conducted by the Airbus CERT team.

What is ETL and why is it a pain to work with? Consider ETL as a container, like AVI is for video files. Reading ETL is similarly frustrating as reading an AVI file without the right codec.

etl-parser tries to solve this problem by including parsers for the following well-known log formats:

• ETW manifest base provider
• TraceLogging
• MOF for kernel log

Why an ETL Parser?

The EVTX log format is fairly well documented, with lots of libraries and tools available today. This is not true for ETL: at the time of development, there is no significant open-source project that we know of and the ETL format is not well documented.

ETL is massively used by Windows system programmers to log useful artifacts:

• C:\Windows\System32\WDI\LogFiles\BootPerfDiagLogger.etl
• C:\Windows\System32\WDI\LogFiles\ShutdownPerfDiagLogger.etl
• NetTrace.etl via netsh
• C:\Windows\System32\WDI\<GUID>\<GUID>\snapshot.etl
• etc.

A lot of new APIs such as Tracelogging or WPP are based on ETW. These APIs are used extensively by Microsoft developers for Windows. Tracelogging is addressed by etl-parser, WPP will be addressed in a future release.

Microsoft offers a lot of consumers that create ETL traces, such as xperf.exe, logman.exe, netsh.exe, etc.

We believe it is a gold mine for DFIR analysts.

Changelog v1.0.1

• fix GUID parsing #1
• fix unhandle tracelogging tag parsing #3
• improve xml convertion

Install

pip install etl-parser

Use

etl-parser offers two scripts. The first script, etl2xml transforms all known ETL events into XML:

etl2xml -i example.etl -o example.xml

The second script, etl2pcap transforms network captures created through netsh into the pcap file format:

netsh start trace capture=yes
netsh stop trace

etl2pcap -i NetTrace.etl -o NetTrace.pcap

You can also use etl-parser as a library:

from etl.etl import IEtlFileObserver, build_from_stream

from etl.system import SystemTraceRecord

from etl.perf import PerfInfo

from etl.event import Event

from etl.trace import Trace

from etl.wintrace import WinTrace



class EtlFileLogger(IEtlFileObserver):

    def on_system_trace(self, event: SystemTraceRecord):

        """Mof kernel message with Process Id and Thread Id"""

        mof = event.get_mof() # Invoke MOF parser



    def on_perfinfo_trace(self, event: PerfInfo):

        """Mof kernel message with timestamp"""

        mof = event.get_mof() # Invoke MOF parser



    def on_trace_record(self, event: Trace):

        """unknown"""



    def on_event_record(self, event: Event):

        """ETW event this is what you search"""

        message = event.parse_tracelogging() # Invoke TraceLogging parser

        message = event.parse_etw() # Invoke Manifest based parser



    def on_win_trace(self, event: WinTrace):

        """unknown"""

        etw = event.parse_etw()



with open("example.etl") as etl_file:

    etl_reader = build_from_stream(etl_file.read())

    etl_reader.parse(EtlFileLogger())

Copyright (C) 2020 airbus-cert

Source: https://github.com/airbus-cert/