Difference between pages "File Carving:SmartCarving" and "Mac OS X"

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'''SmartCarving''' is a [[File Carving|file carving]] technique to recover fragmented files first proposed by [[User:PashaPal|A. Pal]], T. Sencar and [[User:NasirMemon|N. Memon]] in DFRWS 2008. The term '''Smart Carving''' was already proposed in [http://sandbox.dfrws.org/2006/mora/dfrws2006.pdf]
+
{{Expand}}
  
SmartCarving utilizes a combination of structure based validation along with validation of each file's unique content. Results for the SmartCarving technique
+
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]].  
were demonstrated on fragmented jpegs in the DFRWS 2006 and DFRWS 2007 challenges. From these two challenges SmartCarving was able
+
to recover all but one fragmented jpeg file.  
+
  
==History==
+
== Disk image types ==
[[User:NasirMemon|Memon]] et al.[1] presented an efficient algorithm based on a greedy heuristic and alpha-beta pruning for reassembling fragmented images.
+
Building on this work, [[User:NasirMemon|Memon]] et al.[2] researched and introduced sequential hypothesis testing as a an effective mechanism for detecting fragmentation points of file. This paper won the best paper award for DFRWS 2008. The techniques presented in the paper were the foundation for the overall SmartCarving design.
+
  
==Details==
+
Mac OS X has support for various disk image types build-in, some of which are:
After identifying a header block of a specific file type, for example, jpeg, a SmartCarver will analyze each subsequent block to determine if it
+
* read-write disk image (.dmg) some of which use the [[Raw Image Format]]
belongs or does not belong to the starting block. If a block is determined not to belong, then the file is assumed to be fragmented and the  
+
* [[Sparse Image format|Sparse disk image (.spareimage)]]
SmartCarving algorithm looks for the next fragment by matching the data of other available blocks with the first fragment. This process can be
+
* [[Sparse Bundle Image format|Sparse bundle disk image (.sparsebundle)]]
done in parallel for many files.
+
  
==Applications==
+
== Burn Folder ==
There are currently two applications available that utilize SmartCarving, both produced by Digital Assembly:
+
* [[Adroit Photo Forensics]]
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* Adroit Photo Recovery
+
  
== References ==
+
Mac OS X Burn Folder:
* A. Pal and N. Memon, [http://digital-assembly.com/technology/research/pubs/ieee-trans-2006.pdf "Automated reassembly of file fragmented images using greedy algorithms"] in IEEE Transactions on Image processing, February 2006, pp 385­393
+
<pre>
* A. Pal, T. Sencar and N. Memon, [http://digital-assembly.com/technology/research/pubs/dfrws2008.pdf "Detecting File Fragmentation Point Using Sequential Hypothesis Testing"], Digital Investigations, Fall 2008
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$NAME.fpbf
 +
</pre>
  
==External links==
+
This folder normally contains [[Mac OS X Alias Files|alias files]] (similar to LNK files under Windows). Which should have the following signature.
* [http://digital-assembly.com/products/adroit-photo-recovery/ Adroit Photo Recovery]
+
<pre>
* [http://digital-assembly.com/products/adroit-photo-forensics/ Adroit Photo Forensics]
+
00000000  62 6f 6f 6b 00 00 00 00  6d 61 72 6b 00 00 00 00  |book....mark....|
* [http://digital-assembly.com/technology/ Link to SmartCarving Technology and Research]
+
</pre>
* [http://digital-assembly.com Digital Assembly]
+
 
 +
These [[Mac OS X Alias Files|alias files]] contain additional date and time values.
 +
 
 +
Also check the following files for references to deleted .fpbf paths:
 +
<pre>
 +
/Users/$USERNAME/Library/Preferences/com.apple.finder.plist
 +
/Users/$USERNAME/Library/Preferences/com.apple.sidebarlists.plist
 +
</pre>
 +
 
 +
Actual burning of optical media is logged in:
 +
<pre>
 +
/var/log/system.log
 +
/Users/$USERNAME/Library/Logs/DiscRecording.log
 +
/private/var/.logs_exporter/cache/Users/$USERNAME/Library/Logs/DiscRecording.log
 +
</pre>
 +
 
 +
== 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: [http://web.archive.org/web/20090214212148/http://developer.apple.com/technotes/tn/tn1150.html Technical Note TN1150 - HFS Plus Volume Format]
 +
 
 +
Converting HFS/HFS+ date and time values with Python:
 +
<pre>
 +
import datetime
 +
 
 +
print datetime.datetime( 1904, 1, 1 ) + datetime.timedelta( seconds=0xCBDAF25B )
 +
</pre>
 +
 
 +
== Launch Agents ==
 +
<pre>
 +
/System/Library/LaunchAgents/
 +
</pre>
 +
 
 +
== Launch Daemons ==
 +
System-wide:
 +
<pre>
 +
/Library/LaunchDaemons
 +
/System/Library/LaunchDaemons
 +
</pre>
 +
 
 +
These directories contain [[Property list (plist)]] files.
 +
 
 +
== Startup Items ==
 +
<pre>
 +
/Library/StartupItems/
 +
/System/Library/StartupItems/
 +
</pre>
 +
 
 +
== Crash Reporter ==
 +
<pre>
 +
/Library/Application Support/CrashReporter
 +
</pre>
 +
 
 +
== Diagnostic Reports ==
 +
<pre>
 +
/Library/Logs/DiagnosticReports
 +
</pre>
 +
 
 +
== Quarantine event database ==
 +
See [http://menial.co.uk/blog/2011/06/16/mac-quarantine-event-database/]
 +
 
 +
Snow Leopard and earlier
 +
<pre>
 +
/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEvents
 +
</pre>
 +
 
 +
<pre>
 +
SELECT datetime(LSQuarantineTimeStamp + 978307200, "unixepoch") as LSQuarantineTimeStamp, LSQuarantineAgentName, LSQuarantineOriginURLString, LSQuarantineDataURLString from LSQuarantineEvent;
 +
</pre>
 +
 
 +
Lion and later
 +
<pre>
 +
/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV2
 +
</pre>
 +
 
 +
== sleepimage ==
 +
This file is similar to the hibernation file on Windows.
 +
<pre>
 +
/private/var/vm/sleepimage
 +
</pre>
 +
 
 +
Also see: [http://osxdaily.com/2010/10/11/sleepimage-mac/]
 +
 
 +
== 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].
 +
 
 +
== Also see ==
 +
* [[MacOS Process Monitoring]]
 +
* [[Acquiring a MacOS System with Target Disk Mode]]
 +
* [[Converting Binary Plists]]
 +
* [[FileVault Disk Encryption]]
 +
* [[File Vault]]
 +
 
 +
=== Formats ===
 +
* [[Basic Security Module (BSM) file format]]
 +
* [[Property list (plist)]]
 +
 
 +
== External Links ==
 +
* [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]
 +
* [https://code.google.com/p/mac-security-tips/wiki/ALL_THE_TIPS mac-security-tips]
 +
 
 +
=== 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
 +
 
 +
=== iCloud ===
 +
* [http://support.apple.com/kb/HT4865?viewlocale=en_US&locale=en_US iCloud: iCloud security and privacy overview]
 +
 
 +
[[Category:Mac OS X]]
 +
[[Category:Operating systems]]

Revision as of 13:08, 12 June 2014

Information icon.png

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 )

Launch Agents

/System/Library/LaunchAgents/

Launch Daemons

System-wide:

/Library/LaunchDaemons
/System/Library/LaunchDaemons

These directories contain Property list (plist) files.

Startup Items

/Library/StartupItems/
/System/Library/StartupItems/

Crash Reporter

/Library/Application Support/CrashReporter

Diagnostic Reports

/Library/Logs/DiagnosticReports

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

Formats

External Links

Apple Examiner

iCloud