Plaso

About

Plaso is a Python-based suite of tools used for creation of analysis timelines from forensic artifacts acquired from an endpoint.

These timelines are invaluable tools for digital forensic investigators and analysts, enabling them to effectively correlate the vast quantities of information encountered in logs and various forensic artifacts encountered in an intrusion investigation.

The primary tools in the Plaso suite used for this process are log2timeline, psort, and psteal.

• log2timeline - bulk forensic artifact parser
• psort - builds timelines based on output from log2timeline
• psteal - Simply a wrapper for log2timeline and psort

The ext-plaso extension within LimaCharlie allows you to run log2timeline and psort (using the psteal wrapper) against artifacts obtained from an endpoint, such as event logs, registry hives, and various other forensic artifacts. When executed, Plaso will parse and extract information from all acquired evidence artifacts that it has support for. Supported parsers are found here.

Extension Configuration

The ext-plaso extension runs psteal (log2timeline + psort) against the acquired evidence using the following commands:

1. psteal.py --source /path/to/artifact -o dynamic --storage-file $artifact_id.plaso -w $artifact_id.csv

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Upon running psteal.py, a .plaso file and a .csv file are generated. They will be uploaded as LimaCharlie artifacts.

• Resulting .plaso file contains the raw output of log2timeline.py
• Resulting .csv file contains the CSV formatted version of the .plaso file contents

2. pinfo.py $artifact_id.plaso -w $artifact_id_pinfo.json --output_format json

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After psteal.py runs, information is gathered from the resulting .plaso file using the pinfo.py utility and pushed into the ext-plaso sensor timeline as a pinfo event. This event provides a detailed summary with metrics of the processing that occurred, as well as any relevant errors you should be aware of.

The following events will be pushed to the ext-plaso sensor timeline:

• job_queued: indicates that ext-plaso has received and queued a request to process data
• job_started: indicates that ext-plaso has started processing the data
• pinfo: contains the pinfo.py output summarizing the results of the plaso file generation
• plaso: contains the artifact_id of the plaso file that was uploaded to LimaCharlie
• csv: contains the artifact_id of the CSV file that was uploaded to LimaCharlie

Usage & Automation

LimaCharlie can automatically kick off evidence processing with Plaso based off of the artifact ID provided in a D&R rule action, or you can run it manually via the extension.

Velociraptor Triage Acquisition Processing

If you use the LimaCharlie Velociraptor extension, a good use case of ext-plaso would be to trigger Plaso evidence processing upon ingestion of a Velociraptor KAPE files artifact collection.

1. Configure a D&R rule to watch for Velociraptor collection events upon ingestion, and then trigger the Plaso extension:

   Detect:

   op: and
   target: artifact_event
   rules:
       - op: is
         path: routing/log_type
         value: velociraptor
       - op: is
         not: true
         path: routing/event_type
         value: export_complete

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   Respond:

   - action: extension request
     extension action: generate
     extension name: ext-plaso
     extension request:
         artifact_id: '{{ .routing.log_id }}'

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2. Launch a Windows.KapeFiles.Targets artifact collection in the LimaCharlie Velociraptor extension. This instructs Velociraptor to gather all endpoint artifacts defined in this KAPE Target file.

   Argument options:

   • EventLogs=Y - EventLogs only, quicker processing time for proof of concept
   • KapeTriage=Y - full KapeTriage files collection
     

3. Once Velociraptor collects, zips, and uploads the evidence, the previously created D&R rule will send the triage .zip to ext-plaso for processing. Watch the ext-plaso sensor timeline for status and the Artifacts page for the resulting .plaso & .csv output files. See Working with the Output.

MFT Processing

If you use the LimaCharlie Dumper extension, a good use case of ext-plaso would be to trigger Plaso evidence processing upon ingestion of a MFT CSV artifact.

1. Configure a D&R rule to watch for MFT collection events upon ingestion, and then trigger the Plaso extension:

   Detect:

   op: and
   target: artifact_event
   rules:
       - op: is
         path: routing/log_type
         value: mftcsv
       - op: is
         not: true
         path: routing/event_type
         value: export_complete

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   Respond:

   - action: extension request
     extension action: generate
     extension name: ext-plaso
     extension request:
         artifact_id: '{{ .routing.log_id }}'

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2. Launch an MFT dump in the LimaCharlie Dumper extension.
   

3. Once dumper is complete and uploads the evidence, the previously created D&R rule will send the zipped MFT CSV to ext-plaso for processing. Watch the ext-plaso sensor timeline for status and the Artifacts page for the resulting .plaso & .csv output files. See Working with the Output.

Working with the Output

Running the extension generates the following useful outputs:

• pinfo on ext-plaso sensor timeline
  First and foremost, after the completion of a processing job by ext-plaso, it is highly encouraged to analyze the resulting pinfo event on the ext-plaso sensor timeline. This event provides a detailed summary with metrics of the processing that occurred, as well as any relevant errors you should be aware of.
  • Pay close attention to fields such as warnings_by_parser or warnings_by_path_spec which may reveal parser errors that were encountered.
  • Sample output of pinfo showing counts of parsed artifacts nested under storage_counters -- this provides insight as to which, and how many events will be present in your CSV timeline.

"amcache": 986,
"appcompatcache": 4096,
"bagmru": 29,
"chrome_27_history": 29,
"chrome_66_cookies": 246,
"explorer_mountpoints2": 2,
"explorer_programscache": 1,
"filestat": 3495,
"lnk": 160,
"mft": 4790977,
"mrulist_string": 2,
"mrulistex_shell_item_list": 3,
"mrulistex_string": 5,
"mrulistex_string_and_shell_item": 5,
"mrulistex_string_and_shell_item_list": 1,
"msie_webcache": 143,
"msie_zone": 60,
"networks": 4,
"olecf_automatic_destinations": 37,
"olecf_default": 5,
"recycle_bin": 3,
"shell_items": 297,
"total": 5840430,
"user_access_logging": 34,
"userassist": 44,
"utmp": 13,
"windows_boot_execute": 8,
"windows_run": 10,
"windows_sam_users": 16,
"windows_services": 2004,
"windows_shutdown": 8,
"windows_task_cache": 835,
"windows_timezone": 4,
"windows_typed_urls": 3,
"windows_version": 6,
"winevtx": 382674,
"winlogon": 8,
"winreg_default": 654177

Downloadable Artifacts

• plaso artifact
  The downloadable .plaso file contains the raw output of log2timeline.py and can be imported into Timesketch as a timeline.

• csv artifact
  The downloadable .csv file can be easily viewed in any CSV viewer, but a highly recommended tool for this is Timeline Explorer from Eric Zimmerman.