A Python script to parse Windows Prefetch files
Project description
Python script created to parse Windows Prefetch files: Supports XP - Windows 10 Prefetch files
Description
The Windows Prefetch file was put in place to offer performance benefits when launching applications. It just so happens to be one of the more beneficial forensic artifacts regarding evidence of applicaiton execution as well. prefetch.py provides functionality for parsing prefetch files for all current prefetch file versions: 17, 23, 26, and 30.
Features
Specify a single prefetch file or a directory of prefetch files
Automatic version detection - no specification required by the user
On-the-fly type 30 (Windows 10) decompression and parsing
Sort a directory of Prefetch files by last execution time
(Mostly) cross-platform: Windows 10 prefetch files must be parsed from a Windows workstation using this script. All others have been tested on both Windows and Linux
Note: Version 30 (Windows 10): The class being utilized for Windows 10 prefetch file decompression makes use of Python’s ‘ctypes’ module. This module relies on the Windows API; the Analyst must be working from a workstation running at least Windows 8 in order to decompress and parse Windows 10 prefetch files.
Command-Line Options
For now, prefetch.py requires one of two command-line options: --file specifies a single prefetch to point the script at. --directory specifies an entire directory of prefetch files which will be parsed and printed to stdout. When using --directory / -d, remember to include the trailing slash:
dev@computer:~/$ python prefetch.py -h usage: prefetch.py [-h] [-f FILE] [-d DIRECTORY] optional arguments: -h, --help show this help message and exit -f FILE, --file FILE Parse a given Prefetch file -d DIRECTORY, --directory DIRECTORY Parse a directory of Prefetch files -e EXECUTED, --executed EXECUTED Sort a directory of Prefetch files by last execution time -z ZERO, --zero ZERO Identify empty prefetch files
–file
Using the --file / -f switch provides the output below:
dev@computer:~$ python prefetch.py -f PING.EXE-7E94E73E.pf =================== Filename: CMD.EXE =================== Run count: 17 Last executed: 2015-11-14 23:32:03.051396 Additional execution timestamp(s): 2015-11-14 23:27:20.815510 2015-11-14 21:50:33.595482 2015-11-14 03:22:22.545884 2015-11-12 07:31:13.017108 2015-11-12 06:28:31.903824 2015-11-12 06:09:16.828206 2015-11-12 04:26:48.679006 Volume path: \VOLUME{01d11b57aa4f5b10-e8aabf9f} Volume serial number e8aabf9f Resources loaded: 1: \VOLUME{01d11b57aa4f5b10-e8aabf9f}\WINDOWS\SYSTEM32\NTDLL.DLL 2: \VOLUME{01d11b57aa4f5b10-e8aabf9f}\WINDOWS\SYSTEM32\CMD.EXE 3: \VOLUME{01d11b57aa4f5b10-e8aabf9f}\WINDOWS\SYSTEM32\KERNEL32.DLL 4: \VOLUME{01d11b57aa4f5b10-e8aabf9f}\WINDOWS\SYSTEM32\KERNELBASE.DLL 5: \VOLUME{01d11b57aa4f5b10-e8aabf9f}\WINDOWS\SYSTEM32\LOCALE.NLS ... ... ...
–directory
By invoking the --directory / -d flag, the Analyst is able to parse an entire directory of Prefetch files at once.
–executed
Sort a directory of Prefetch files by last execution time. The output looks like this:
dev@computer:~$ python prefetch.py -e Prefetch/ 2015-10-22 18:11:34.918518 - CONHOST.EXE 2015-10-22 18:11:34.555482 - MCSCRIPT_INUSE.EXE 2015-10-22 18:10:52.214248 - ENTVUTIL.EXE 2015-10-22 18:10:15.439572 - SEARCHFILTERHOST.EXE 2015-10-22 18:10:15.285556 - SEARCHPROTOCOLHOST.EXE ... ... ...
–zero
Recently I encountered multiple zero-byte Prefetch files during an investigation. This broke some of the functionality in my script, which was expecting data instead of null values. I modified the script not to break when it encounters empty Prefetch files. Additionally, I added the -z/--zero flag which will help an Analyst identify them up front. This piece of the script was cobbled together rather quickly in order to fix my Master copy - I am working on adding a bit of finesse in the “Zero-byte-detection-refinement” branch.
Here is its output, for now:
dev@computer:~$ python prefetch.py -z Prefetch/ ========================== Zero-byte Prefetch Files ========================== WERMGR.EXE-0F2AC88C.pf WMIPRVSE.EXE-1628051C.pf
Testing
Testing on the prefetch file types below has been completed successfully:
Windows XP (version 17)
Windows 7 (version 23)
Windows 8.1 (version 26)
Windows 10 (version 30)
References
This project would not have been possible without the work of others much smarter than I. The prefetch file format is not officially documented by Microsoft and has been understood through reverse engineering, and trial-and-error.
Additionally, Without the excellent work by Francesco Picasso in understanding the Windows 10 prefetch compression method, I would not have been able to get Windows 10 parsed here. I use a modified version of his decompression script in prefetch.py. Francesco’s original script can be found at the link below:
To gain a better understanding of the prefetch file format, check out the following resources; which were all used as references for the creation of my script:
Python Requirements
from argparse import ArgumentParser
import binascii
import collections
import ctypes
from datetime import datetime,timedelta
import json
import os
import struct
import sys
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