Difference between pages "Mac OS X" and "Remnant Data"

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Remnant Data is data that is unintentionally left behind on computer media. In forensic usage, remnant data is typically left behind after attempts have been made to delete the data, after the data has been forgotten, or after the media on which the data resides has been decomissioned.
  
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]].  
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Remnant data appears at all levels of modern computer systems:
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* Computer systems that are discarded.
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* Partitions in hard drives that are deleted.
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* Files on hard drives that are deleted but not overwritten.
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* Snippets of text in Microsoft Word files.
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* Heap variables that are freed with '''free()'''
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* Automatic variables left on the stack of languages like C or garbage collected in languages like Java.
  
== Burn Folder ==
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Originally the phrase "remnant data" was used to describe data left behind on magnetic recording media such as tapes and floppy disks. On these kinds of media it was suggested that previous generations of data could be recovered---a process that is easy to observe with analog cassette and reel-to-reel tapes.
  
Mac OS X Burn Folder:
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=Papers=
<pre>
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Byers, Simon. [[Media:Scalable Exploitation.pdf|Scalable Exploitation of, and Responses to Information Leakage Through Hidden Data in Published Documents]], AT&T Research, April 2003
$NAME.fpbf
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</pre>
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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.
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Chow, J., B. Pfaff, T. Garfinkel, K. Christopher, M. Rosenblum, 
<pre>
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[[Media:Image:Tainbochs.pdf|Understanding Data Lifetime via Whole System Simulation]], Proceedings of the 13th USENIX Security Symposium, 2004.
00000000  62 6f 6f 6b 00 00 00 00  6d 61 72 6b 00 00 00 00  |book....mark....|
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</pre>
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These [[Mac OS X Alias Files|alias files]] contain additional date and time values.
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Garfinkel, S. and Shelat, A., "Remembrance of Data Passed: A Study of Disk Sanitization Practices," IEEE Security and Privacy, January/February 2003.
  
Also check: ~/Library/Preferences/com.apple.finder.plist
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=See Also=
For references to deleted .fpbf paths.
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* [Sanitizing Tools]
 
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Actual burning of optical media is logged in:
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/var/log/system.log
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/Users/$USERNAME/Library/Logs/DiscRecording.log
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/private/var/.logs_exporter/cache/Users/$USERNAME/Library/Logs/DiscRecording.log
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== HFS/HFS+ date and time values ==
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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.
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Converting HFS/HFS+ date and time values with Python:
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<pre>
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import datetime
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print datetime.datetime( 1904, 1, 1 ) + datetime.timedelta( seconds=0xCBDAF25B )
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</pre>
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== Quarantine event database ==
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See [http://menial.co.uk/blog/2011/06/16/mac-quarantine-event-database/]
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Snow Leopard and earlier
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<pre>
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/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEvents
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</pre>
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<pre>
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SELECT datetime(LSQuarantineTimeStamp + 978307200, "unixepoch") as LSQuarantineTimeStamp, LSQuarantineAgentName, LSQuarantineOriginURLString, LSQuarantineDataURLString from LSQuarantineEvent;
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</pre>
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Lion and later
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<pre>
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/Users/$USER/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV2
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</pre>
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== Package Files (.PKG) ==
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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].
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== Also see ==
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* [[MacOS Process Monitoring]]
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* [[Acquiring a MacOS System with Target Disk Mode]]
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* [[Converting Binary Plists]]
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* [[FileVault Disk Encryption]]
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* [[File Vault]]
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== External Links ==
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* [http://www.apple.com/macosx/ Official website]
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* [http://en.wikipedia.org/wiki/OS_X Wikipedia entry on OS X]
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* [http://menial.co.uk/blog/2011/06/16/mac-quarantine-event-database/ Quarantine event database]
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* [http://www2.tech.purdue.edu/cit/Courses/cit556/readings/MacForensicsCraiger.pdf Mac Forensics: Mac OS X and the HFS+ File System] by P. Craiger
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=== Apple Examiner ===
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* [http://www.appleexaminer.com/ The Apple Examiner]
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* [http://www.appleexaminer.com/MacsAndOS/Analysis/USBOSX/USBOSX.html USB Entries on OS X]
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* [http://www.appleexaminer.com/Downloads/MacForensics.pdf Macintosh Forensics - A Guide for the Forensically Sound Examination of a Macintosh Computer] by Ryan R. Kubasiak
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[[Category:Mac OS X]]
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[[Category:Operating systems]]
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Revision as of 09:36, 16 March 2007

Remnant Data is data that is unintentionally left behind on computer media. In forensic usage, remnant data is typically left behind after attempts have been made to delete the data, after the data has been forgotten, or after the media on which the data resides has been decomissioned.

Remnant data appears at all levels of modern computer systems:

  • Computer systems that are discarded.
  • Partitions in hard drives that are deleted.
  • Files on hard drives that are deleted but not overwritten.
  • Snippets of text in Microsoft Word files.
  • Heap variables that are freed with free()
  • Automatic variables left on the stack of languages like C or garbage collected in languages like Java.

Originally the phrase "remnant data" was used to describe data left behind on magnetic recording media such as tapes and floppy disks. On these kinds of media it was suggested that previous generations of data could be recovered---a process that is easy to observe with analog cassette and reel-to-reel tapes.

Papers

Byers, Simon. Scalable Exploitation of, and Responses to Information Leakage Through Hidden Data in Published Documents, AT&T Research, April 2003

Chow, J., B. Pfaff, T. Garfinkel, K. Christopher, M. Rosenblum, Understanding Data Lifetime via Whole System Simulation, Proceedings of the 13th USENIX Security Symposium, 2004.

Garfinkel, S. and Shelat, A., "Remembrance of Data Passed: A Study of Disk Sanitization Practices," IEEE Security and Privacy, January/February 2003.

See Also

  • [Sanitizing Tools]