Difference between pages "Forensic corpora" and "Prefetch"

From ForensicsWiki
(Difference between pages)
Jump to: navigation, search
(Log files)
 
 
Line 1: Line 1:
This page describes large-scale corpora of forensically interesting information that are available for those involved in forensic research.
+
{{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 was 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]].
  
=Disk Images=
+
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.
  
''The Garfinkel Used Hard drive Collection Project.'' Between 1998 and 2006, Garfinkel acquired 1250+ hard drives on the secondary market. These hard drive images have proven invaluable in performing a range of studies such as the developing of new forensic techniques [13]  and the sanitization practices of computer users.
+
== 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.
  
=Network Packets=
+
== 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.
  
''The DARPA Intrusion Detection Evaluation.'' In 1998, 1999 and 2000 the Information Systems Technology Group at MIT Lincoln Laboratory created a test network complete with simulated servers, clients, clerical workers, programmers, and system managers. Baseline traffic was collected. The systems on the network were then “attacked” by simulated hackers. Some of the attacks were well-known at the time, while others were developed for the purpose of the evaluation.  
+
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.
  
=Email messages=
+
== See Also ==
 +
* [[SuperFetch]]
  
''The Enron Corpus'' of email messages that were seized by the Federal Energy Regulatory Commission during its investigation of Enron.
+
== External Links ==
 
+
* [http://www.mitec.cz/wfa.html Windows File Analyzer] - Parses Prefetch files, thumbnail databases, shortcuts, index.dat files, and the recycle bin
* http://www.cs.cmu.edu/~enron
+
* [http://www.microsoft.com/whdc/driver/kernel/XP_kernel.mspx#ECLAC Microsoft's description of Prefetch when Windows XP was introduced]
* http://www.enronemail.com/
+
* [http://msdn.microsoft.com/msdnmag/issues/01/12/XPKernel/default.aspx More detail from Microsoft]
 
+
=Log files=
+
[http://crawdad.cs.dartmouth.edu/index.php CRAWDAD] is a community archive for wireless data.
+
 
+
=Voice=
+
CALLFRIEND is a database of recorded English conversations. A total of 60 recorded conversations are available from the University of Pennsylvania at a cost of $600.
+
 
+
TalkBank in an online database of spoken language. The project was originally funded between 1999 and 2004 by two National Science Foundation grants; ongoing support is provided by two NSF grants and one NIH grant.
+
 
+
 
+
=Other Corpora=
+
The [http://corpus.canterbury.ac.nz/ Canterbury Corpus] is a set of files used for testing lossless compression algorithms. The corpus consists of 11 natural files, 4 artificial files, 3 large files, and a file with the first million digits of pi.  You can also find a copyof the Calgaruy Corpus at the website, which was the defacto standard for testing lossless compression algorithms in the 1990s.
+

Revision as of 08:47, 21 August 2007

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 was 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.

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.

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.

See Also

External Links