Difference between pages "File Format Identification" and "Mac OS X"

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File Format Identification is the process of figuring out the format of a sequence of bytes. Operating systems typically do this by file extension or by embedded MIME information. Forensic applications need to identify file types by content.
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{{Expand}}
  
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Apple Inc.'s Macintosh OS X (pronounced "'''OS Ten'''") is the operating system distributed with Apple computers. It includes heavily used several programs by default, including [[Apple Mail]], a web browser called [[Apple Safari | Safari]], and an [[Apple Address Book]], and [[iCal]].
  
=Tools=
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== Disk image types ==
==libmagic==
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* Written in C.
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* Rules in /usr/share/file/magic and compiled at runtime.
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* Powers the Unix “file” command, but you can also call the library directly from a C program.
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* http://sourceforge.net/projects/libmagic
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==Digital Preservation Efforts==
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Mac OS X has support for various disk image types build-in, some of which are:
PRONOM is  a project of the National Archives of the United Kingdom to develop a registry of file types. A similar project was started by JSTOR and Harvard as the JSTOR/Harvard Object Validation Environment. Attempts are now underway to merge these two efforts in the Global Digital Format Registry and the Universal Digital Format Registry.
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* [[Raw Image Format|read-write disk image (.dmg)]]
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* [[Sparse Image format|Sparse disk image (.spareimage)]]
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* [[Sparse Bundle Image format|Sparse bundle disk image (.sparsebundle)]]
  
The UK National Archives developed the Digital Record Object Identification (DROID) tool, an "automatic file format identification tool." This tool is written in Java and can be downloaded from SourgeForge.
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== Burn Folder ==
  
See:
+
Mac OS X Burn Folder:
* [http://www.nationalarchives.gov.uk/PRONOM/Default.aspx  PRONOM]
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<pre>
* [http://hul.harvard.edu/jhove/ JHOVE]
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$NAME.fpbf
* [https://wiki.ucop.edu/display/JHOVE2Info/Home JHOVE2]
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</pre>
* [http://www.gdfr.info/  GDFR]
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* [http://www.udfr.org/  UDFR]
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* [http://droid.sourceforge.net DROID download]
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==TrID==
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This folder normally contains [[Mac OS X Alias Files|alias files]] (similar to LNK files under Windows). Which should have the following signature.
* XML config file
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<pre>
* Closed source; free for non-commercial use
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00000000  62 6f 6f 6b 00 00 00 00  6d 61 72 6b 00 00 00 00  |book....mark....|
* http://mark0.net/soft-trid-e.html
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</pre>
  
==Forensic Innovations File Investigator TOOLS==
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These [[Mac OS X Alias Files|alias files]] contain additional date and time values.
* Proprietary, but free trial available.
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* Available as consumer applications and OEM API.
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* Identifies 3,000+ file types, using multiple methods to maintain high accuracy.
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* Extracts metadata for many of the supported file types.
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* http://www.forensicinnovations.com/fitools.html
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==Stellent/Oracle Outside-In==
+
Also check the following files for references to deleted .fpbf paths:
* Proprietary but free demo.
+
<pre>
* http://www.oracle.com/technology/products/content-management/oit/oit_all.html
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/Users/$USERNAME/Library/Preferences/com.apple.finder.plist
 +
/Users/$USERNAME/Library/Preferences/com.apple.sidebarlists.plist
 +
</pre>
  
==[[Forensic Assistant]]==
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Actual burning of optical media is logged in:
* Proprietary.
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<pre>
* Provides detection of password protected archives, some files of cryptographic programs, Pinch/Zeus binary reports, etc.
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/var/log/system.log
* http://nhtcu.ru/0xFA_eng.html
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/Users/$USERNAME/Library/Logs/DiscRecording.log
[[Category:Tools]]
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/private/var/.logs_exporter/cache/Users/$USERNAME/Library/Logs/DiscRecording.log
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</pre>
  
=Data Sets=
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== HFS/HFS+ date and time values ==
If you are working in the field of file format identification, please consider reporting the results of your algorithm with one of these publicly available data sets:
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* NPS govdocs1m - a corpus of 1 million files that can be redistributed without concern of copyright or PII. Download from http://domex.nps.edu/corp/files/govdocs1/
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* The NPS Disk Corpus - a corpus of realistic disk images that contain no PII. Information is at: http://digitalcorpora.org/?s=nps
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=Bibliography=
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In HFS+ date and time values are stored in an unsigned 32-bit integer containing the number of seconds since January 1, 1904 at 00:00:00 (midnight) UTC (GMT). This is slightly different from HFS where the date and time value are stored using the local time. The maximum representable date is February 6, 2040 at 06:28:15 UTC (GMT). The date values do not account for leap seconds. They do include a leap day in every year that is evenly divisible by four. This is sufficient given that the range of representable dates does not contain 1900 or 2100, neither of which have leap days. Also see: [http://web.archive.org/web/20090214212148/http://developer.apple.com/technotes/tn/tn1150.html Technical Note TN1150 - HFS Plus Volume Format]
Current research papers on the file format identification problem. Most of these papers concern themselves with identifying file format of a few file sectors, rather than an entire file. '''Please note that this bibliography is in chronological order!'''
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 +
Converting HFS/HFS+ date and time values with Python:
 +
<pre>
 +
import datetime
  
;2001
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print datetime.datetime( 1904, 1, 1 ) + datetime.timedelta( seconds=0xCBDAF25B )
 +
</pre>
  
* Mason McDaniel, [[Media:Mcdaniel01.pdf|Automatic File Type Detection Algorithm]], Masters Thesis, James Madison University,2001
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== Quarantine event database ==
 +
See [http://menial.co.uk/blog/2011/06/16/mac-quarantine-event-database/]
  
; 2003
+
Snow Leopard and earlier
 +
<pre>
 +
/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEvents
 +
</pre>
  
* [http://www2.computer.org/portal/web/csdl/abs/proceedings/hicss/2003/1874/09/187490332a.pdf Content Based File Type Detection Algorithms], Mason McDaniel and M. Hossain Heydari, 36th Annual Hawaii International Conference on System Sciences (HICSS'03) - Track 9, 2003.
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<pre>
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SELECT datetime(LSQuarantineTimeStamp + 978307200, "unixepoch") as LSQuarantineTimeStamp, LSQuarantineAgentName, LSQuarantineOriginURLString, LSQuarantineDataURLString from LSQuarantineEvent;
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</pre>
  
; 2005
+
Lion and later
 +
<pre>
 +
/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV2
 +
</pre>
  
* Fileprints: identifying file types by n-gram analysis, LiWei-Jen, Wang Ke, Stolfo SJ, Herzog B..,  IProceeding of the 2005 IEEE workshop on information assurance, 2005. ([http://www.itoc.usma.edu/workshop/2005/Papers/Follow%20ups/FilePrintPresentation-final.pdf Presentation Slides])  ([http://www1.cs.columbia.edu/ids/publications/FilePrintPaper-revised.pdf PDF])
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== sleepimage ==
 +
This file is similar to the hibernation file on Windows.
 +
<pre>
 +
/private/var/vm/sleepimage
 +
</pre>
  
* Douglas J. Hickok, Daine Richard Lesniak, Michael C. Rowe, File Type Detection Technology,  2005 Midwest Instruction and Computing Symposium.([http://www.micsymposium.org/mics_2005/papers/paper7.pdf PDF])
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Also see: [http://osxdaily.com/2010/10/11/sleepimage-mac/]
  
; 2006
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== Package Files (.PKG) ==
 +
Package Files (.PKG) are XAR archives [http://en.wikipedia.org/wiki/Xar_(archiver)] that contain a cpio archive and metadata [http://s.sudre.free.fr/Stuff/Ivanhoe/FLAT.html].
  
* Karresand Martin, Shahmehri Nahid [http://ieeexplore.ieee.org/iel5/10992/34632/01652088.pdf  File type identification of data fragments by their binary structure. ], Proceedings of the IEEE workshop on information assurance, pp.140–147, 2006.([http://www.itoc.usma.edu/workshop/2006/Program/Presentations/IAW2006-07-3.pdf Presentation Slides])
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== Also see ==
 +
* [[MacOS Process Monitoring]]
 +
* [[Acquiring a MacOS System with Target Disk Mode]]
 +
* [[Converting Binary Plists]]
 +
* [[FileVault Disk Encryption]]
 +
* [[File Vault]]
  
* Gregory A. Hall, Sliding Window Measurement for File Type Identification, Computer Forensics and Intrusion Analysis Group, ManTech Security and Mission Assurance, 2006. ([http://www.mantechcfia.com/SlidingWindowMeasurementforFileTypeIdentification.pdf PDF])
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== External Links ==
  
* FORSIGS; Forensic Signature Analysis of the Hard Drive for Multimedia File Fingerprints, John Haggerty and Mark Taylor, IFIP TC11 International Information Security Conference, 2006, Sandton, South Africa.
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* [http://www.apple.com/macosx/ Official website]
 +
* [http://en.wikipedia.org/wiki/OS_X Wikipedia entry on OS X]
 +
* [http://menial.co.uk/blog/2011/06/16/mac-quarantine-event-database/ Quarantine event database]
 +
* [http://www2.tech.purdue.edu/cit/Courses/cit556/readings/MacForensicsCraiger.pdf Mac Forensics: Mac OS X and the HFS+ File System] by P. Craiger
 +
* [http://web.me.com/driley/iWeb/Previous_files/Directory_Services_Overview.pdf Mac OS X Directory Services Integration including Active Directory]
 +
* [http://digitalinvestigation.wordpress.com/2012/04/04/geek-post-nskeyedarchiver-files-what-are-they-and-how-can-i-use-them/ NSKeyedArchiver files – what are they, and how can I use them?]
 +
* [http://krypted.com/mac-os-x/command-line-alf-on-mac-os-x/ Command Line ALF on Mac OS X]
 +
* [http://newosxbook.com/DMG.html Demystifying the DMG File Format]
  
* Martin Karresand , Nahid Shahmehri, "Oscar -- Using Byte Pairs to Find File Type and Camera Make of Data Fragments," Annual Workshop on Digital Forensics and Incident Analysis, Pontypridd, Wales, UK, pp.85-94, Springer-Verlag, 2006.  
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=== Apple Examiner ===
 +
* [http://www.appleexaminer.com/ The Apple Examiner]
 +
* [http://www.appleexaminer.com/MacsAndOS/Analysis/USBOSX/USBOSX.html USB Entries on OS X]
 +
* [http://www.appleexaminer.com/Downloads/MacForensics.pdf Macintosh Forensics - A Guide for the Forensically Sound Examination of a Macintosh Computer] by Ryan R. Kubasiak
  
; 2007
+
[[Category:Mac OS X]]
 
+
[[Category:Operating systems]]
* Karresand M., Shahmehri N., [http://dx.doi.org/10.1007/0-387-33406-8_35 Oscar: File Type Identification of Binary Data in Disk Clusters and RAM Pages], Proceedings of IFIP International Information Security Conference: Security and Privacy in Dynamic Environments (SEC2006), Springer, ISBN 0-387-33405-x, pp.413-424, Karlstad, Sweden, May 2006.
+
 
+
* Robert F. Erbacher and John Mulholland, "Identification and Localization of Data Types within Large-Scale File Systems," Proceedings of the 2nd International Workshop on Systematic Approaches to Digital Forensic Engineering, Seattle, WA, April 2007.
+
 
+
* Ryan M. Harris, "Using Artificial Neural Networks for Forensic File Type Identification," Master's Thesis, Purdue University, May 2007. ([https://www.cerias.purdue.edu/tools_and_resources/bibtex_archive/archive/2007-19.pdf PDF])
+
 
+
* Predicting the Types of File Fragments, William Calhoun, Drue Coles, DFRWS 2008. ([http://www.dfrws.org/2008/proceedings/p14-calhoun_pres.pdf Presentation Slides])  ([http://www.dfrws.org/2008/proceedings/p14-calhoun.pdf PDF])
+
 
+
* Sarah J. Moody and Robert F. Erbacher, [http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=04545366 SÁDI – Statistical Analysis for Data type Identification], 3rd International Workshop on Systematic Approaches to Digital Forensic Engineering, 2008.
+
 
+
; 2008
+
 
+
* Mehdi Chehel Amirani, Mohsen Toorani, and Ali Asghar Beheshti Shirazi, [http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4625611 A New Approach to Content-based File Type Detection], Proceedings of the 13th IEEE Symposium on Computers and Communications (ISCC'08), pp.1103-1108, July 2008.  ([http://arxiv.org/ftp/arxiv/papers/1002/1002.3174.pdf PDF])
+
 
+
; 2009
+
* Roussev, Vassil, and Garfinkel, Simson, "File Classification Fragment-The Case for Specialized Approaches," Systematic Approaches to Digital Forensics Engineering (IEEE/SADFE 2009), Oakland, California. ([http://simson.net/clips/academic/2009.SADFE.Fragments.pdf PDF])
+
 
+
* Irfan Ahmed, Kyung-suk Lhee, Hyunjung Shin and ManPyo Hong, [http://www.springerlink.com/content/g2655k2044615q75/ On Improving the Accuracy and Performance of Content-based File Type Identification], Proceedings of the 14th Australasian Conference on Information Security and Privacy (ACISP 2009), pp.44-59, LNCS (Springer), Brisbane, Australia, July 2009.
+
 
+
; 2010
+
*Irfan Ahmed, Kyung-suk Lhee, Hyunjung Shin and ManPyo Hong, [http://www.alphaminers.net/sub05/sub05_03.php?swf_pn=5&swf_sn=3&swf_pn2=3    Fast File-type Identification], Proceedings of the 25th ACM Symposium on Applied Computing (ACM SAC 2010), ACM, Sierre, Switzerland, March 2010.
+
 
+
;2011
+
*Irfan Ahmed, Kyung-Suk Lhee, Hyun-Jung Shin, Man-Pyo Hong, [http://link.springer.com/chapter/10.1007/978-3-642-24212-0_5 Fast Content-Based File Type Identification], Proceedings of the 7th Annual IFIP WG 11.9 International Conference on Digital Forensics, Orlando, FL, USA, February, 2011
+
[[Category:Bibliographies]]
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Revision as of 01:22, 20 April 2013

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

Apple Inc.'s Macintosh OS X (pronounced "OS Ten") is the operating system distributed with Apple computers. It includes heavily used several programs by default, including Apple Mail, a web browser called Safari, and an Apple Address Book, and iCal.

Disk image types

Mac OS X has support for various disk image types build-in, some of which are:

Burn Folder

Mac OS X Burn Folder:

$NAME.fpbf

This folder normally contains alias files (similar to LNK files under Windows). Which should have the following signature.

00000000  62 6f 6f 6b 00 00 00 00  6d 61 72 6b 00 00 00 00  |book....mark....|

These alias files contain additional date and time values.

Also check the following files for references to deleted .fpbf paths:

/Users/$USERNAME/Library/Preferences/com.apple.finder.plist
/Users/$USERNAME/Library/Preferences/com.apple.sidebarlists.plist

Actual burning of optical media is logged in:

/var/log/system.log
/Users/$USERNAME/Library/Logs/DiscRecording.log
/private/var/.logs_exporter/cache/Users/$USERNAME/Library/Logs/DiscRecording.log

HFS/HFS+ date and time values

In HFS+ date and time values are stored in an unsigned 32-bit integer containing the number of seconds since January 1, 1904 at 00:00:00 (midnight) UTC (GMT). This is slightly different from HFS where the date and time value are stored using the local time. The maximum representable date is February 6, 2040 at 06:28:15 UTC (GMT). The date values do not account for leap seconds. They do include a leap day in every year that is evenly divisible by four. This is sufficient given that the range of representable dates does not contain 1900 or 2100, neither of which have leap days. Also see: Technical Note TN1150 - HFS Plus Volume Format

Converting HFS/HFS+ date and time values with Python:

import datetime

print datetime.datetime( 1904, 1, 1 ) + datetime.timedelta( seconds=0xCBDAF25B )

Quarantine event database

See [1]

Snow Leopard and earlier

/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEvents
SELECT datetime(LSQuarantineTimeStamp + 978307200, "unixepoch") as LSQuarantineTimeStamp, LSQuarantineAgentName, LSQuarantineOriginURLString, LSQuarantineDataURLString from LSQuarantineEvent;

Lion and later

/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV2

sleepimage

This file is similar to the hibernation file on Windows.

/private/var/vm/sleepimage

Also see: [2]

Package Files (.PKG)

Package Files (.PKG) are XAR archives [3] that contain a cpio archive and metadata [4].

Also see

External Links

Apple Examiner