Description

The Windows application prefetch mechanism 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

• CSV output support

• (Limited) Windows 10 support - Windows 10 prefetch files must be parsed from a Windows 8+ workstation

Command-Line Options

For now, prefetch.py requires only one command-line option: --file can specify a single Prefetch file, or a directory of Prefetch files to parse:

dev@computer:~$ ./prefetch.py -h
usage: prefetch.py [-h] [-c] [-f FILE]

optional arguments:
  -h, --help            show this help message and exit
  -c, --csv             Present results in CSV format
  -f FILE, --file FILE  Parse a given Prefetch file

Single Prefetch File

Using the --file / -f switch with a single prefetch file results in the output below:

dev@computer:~$ python prefetch.py -f CMD.EXE-4A81B364.pf

=====================
CMD.EXE-4A81B364.pf
=====================

Executable Name: CMD.EXE

Run count: 2
Last Executed: 2016-01-16 20:26:42.515108

Volume Information:
    Volume Name: \DEVICE\HARDDISKVOLUME2
    Creation Date: 2016-01-16 21:15:18.109374
    Serial Number: 88008c2f

Directory Strings:
    \DEVICE\HARDDISKVOLUME2\WINDOWS
    \DEVICE\HARDDISKVOLUME2\WINDOWS\BRANDING
    \DEVICE\HARDDISKVOLUME2\WINDOWS\BRANDING\BASEBRD
    \DEVICE\HARDDISKVOLUME2\WINDOWS\GLOBALIZATION
    \DEVICE\HARDDISKVOLUME2\WINDOWS\GLOBALIZATION\SORTING
    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32

Resources loaded:

1:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\NTDLL.DLL
2:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\KERNEL32.DLL
3:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\APISETSCHEMA.DLL
4:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\KERNELBASE.DLL
5:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\LOCALE.NLS
6:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\CMD.EXE
7:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\MSVCRT.DLL
8:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\WINBRAND.DLL
9:    \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\USER32.DLL
10:   \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\GDI32.DLL
11:   \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\LPK.DLL
12:   \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\USP10.DLL
13:   \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\IMM32.DLL
14:   \DEVICE\HARDDISKVOLUME2\WINDOWS\SYSTEM32\MSCTF.DLL
15:   \DEVICE\HARDDISKVOLUME2\WINDOWS\BRANDING\BASEBRD\BASEBRD.DLL
16:   \DEVICE\HARDDISKVOLUME2\WINDOWS\GLOBALIZATION\SORTING\SORTDEFAULT.NLS

Muliple Prefetch Files

Use the same syntax as above, but point the script to a directory of Prefetch files.

CSV Format

Using the --csv / -c flag will provide results in CSV format:

Last Executed, Executable Name, Run Count
2016-01-20 16:01:27.680128, ADOBEIPCBROKER.EXE-c8d02fab, 1
2016-01-20 16:59:42.077480, CREATIVE CLOUD UNINSTALLER.EX-216b8ea8, 1
2016-01-19 18:07:18.101626, MSIEXEC.EXE-a2d55cb6, 37237
2016-01-20 16:11:15.818394, ACRODIST.EXE-782bc2b2, 1

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:

w10pfdecomp.py

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:

ForensicsWiki: Windows Prefetch File Format

Libyal Project: libscca

Zena Forensics: A first look at Windows 10 Prefetch files