Difference between pages "Category talk:Disk imaging tools" and "Prefetch"

From Forensics Wiki
(Difference between pages)
Jump to: navigation, search
(New page: This page was a mistake and should be deleted. ~~~~)
 
m (External Links)
 
Line 1: Line 1:
This page was a mistake and should be deleted. [[User:Jessek|Jessek]] 17:07, 12 April 2007 (PDT)
+
{{Expand}}
 +
Windows Prefetch files, introduced in [[Windows|Windows XP]], are designed to speed up the application startup process. Prefetch files contain the name of the executable, a Unicode list of DLLs used by that executable, a count of how many times the executable has been run, and a timestamp indicating the last time the program was run. Although Prefetch is present in Windows 2003, by default it is only enabled for boot prefetching. The feature is also found in [[Windows Vista]], where it has been augmented with [[SuperFetch]], [[ReadyBoot]], and [[ReadyBoost]].
 +
 
 +
Up to 128 Prefetch files are stored in the <tt>%SystemRoot%\Prefetch</tt> directory [http://blogs.msdn.com/ryanmy/archive/2005/05/25/421882.aspx]. Each file in that directory should contain the name of the application (up to eight (?) characters), a dash, and then an eight character hash of the location from which that application was run, and a <tt>.pf</tt> extension. The filenames should be all uppercase except for the extension. The format of hashes is not known. A sample filename for [[md5deep]] would look like: <tt>MD5DEEP.EXE-4F89AB0C.pf</tt>. If an application is run from two different locations on the drive (i.e. the user runs <tt>C:\md5deep.exe</tt> and then <tt>C:\Apps\Hashing\md5deep.exe</tt>), there will be two different prefetch files in the Prefetch folder.
 +
 
 +
== Timestamps ==
 +
Both the [[NTFS]] timestamps for a Prefetch file and the timestamp embedded in each Prefetch file contain valuable information. The creation date of the file indicates the first time the application was executed. Both the modification date of the file and the embedded timestamp indicate the last time the application was executed.
 +
 
 +
== MetaData ==
 +
The timestamp embedded within the Prefetch file is a 64-bit (QWORD) [http://msdn2.microsoft.com/en-us/library/ms724284.aspx FILETIME] object located at offset 0x78 from the beginning of the file on [[Windows]] XP.
 +
 
 +
The run count, or number of times the application has been run, is a 4-byte (DWORD) value located at offset 0x90 from the beginning of the file on [[Windows]] XP.
 +
 
 +
== See Also ==
 +
* [[SuperFetch]]
 +
 
 +
== External Links ==
 +
* [http://milo2012.wordpress.com/2009/10/19/windows-prefetch-folder-tool/ Prefetch-Tool Script] - Python looks Prefetch files up on a web server.
 +
* [http://www.mitec.cz/wfa.html Windows File Analyzer] - Parses Prefetch files, thumbnail databases, shortcuts, index.dat files, and the recycle bin
 +
* [http://www.microsoft.com/whdc/driver/kernel/XP_kernel.mspx#ECLAC Microsoft's description of Prefetch when Windows XP was introduced]
 +
* [http://msdn.microsoft.com/msdnmag/issues/01/12/XPKernel/default.aspx More detail from Microsoft]
 +
* [http://www.tzworks.net/prototype_page.php?proto_id=1 Windows Prefetch parser] Free tool that can be run on Windows, Linux or Mac OS-X.

Revision as of 10:53, 7 February 2011

Information icon.png

Please help to improve this article by expanding it.
Further information might be found on the discussion page.

Windows Prefetch files, introduced in Windows XP, are designed to speed up the application startup process. Prefetch files contain the name of the executable, a Unicode list of DLLs used by that executable, a count of how many times the executable has been run, and a timestamp indicating the last time the program was run. Although Prefetch is present in Windows 2003, by default it is only enabled for boot prefetching. The feature is also found in Windows Vista, where it has been augmented with SuperFetch, ReadyBoot, and ReadyBoost.

Up to 128 Prefetch files are stored in the %SystemRoot%\Prefetch directory [1]. Each file in that directory should contain the name of the application (up to eight (?) characters), a dash, and then an eight character hash of the location from which that application was run, and a .pf extension. The filenames should be all uppercase except for the extension. The format of hashes is not known. A sample filename for md5deep would look like: MD5DEEP.EXE-4F89AB0C.pf. If an application is run from two different locations on the drive (i.e. the user runs C:\md5deep.exe and then C:\Apps\Hashing\md5deep.exe), there will be two different prefetch files in the Prefetch folder.

Contents

Timestamps

Both the NTFS timestamps for a Prefetch file and the timestamp embedded in each Prefetch file contain valuable information. The creation date of the file indicates the first time the application was executed. Both the modification date of the file and the embedded timestamp indicate the last time the application was executed.

MetaData

The timestamp embedded within the Prefetch file is a 64-bit (QWORD) FILETIME object located at offset 0x78 from the beginning of the file on Windows XP.

The run count, or number of times the application has been run, is a 4-byte (DWORD) value located at offset 0x90 from the beginning of the file on Windows XP.

See Also

External Links