Difference between pages "Google Chrome" and "OLE Compound File"

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Google Chrome is a [[Web Browser|web browser]] developed by Google Inc.
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The '''Object Linking and Embedding (OLE) Compound File (CF)''' is used in other file formats as its underlying container file.
 +
It allows data to be stored in multiple streams.  
  
== Configuration ==
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The OLECF is also known as:
The Google Chrome configuration can be found in the '''Preferences''' file.
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* Compound Binary File (current name used by [[Microsoft]])
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* Compound Document File (name used by [[OpenOffice]])
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* OLE2 file
  
On Linux
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== MIME types ==
<pre>
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/home/$USER/.config/google-chrome/Default/Preferences
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</pre>
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On MacOS-X
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Because the OLECF by itself is just a container it does not use a mime type.
<pre>
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A mime type assigned to an OLECF refers to its contents.
/Users/$USER/Library/Application Support/Google/Chrome/Default/Preferences
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</pre>
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On Windows XP
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== File signature ==
<pre>
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C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Google\Chrome\User Data\Default\Preferences
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</pre>
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On Windows Vista and later
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The OLECF has the following file signature:
<pre>
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hexadecimal: d0 cf 11 e0 a1 b1 1a e1
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\Default\Preferences
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</pre>
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Or for '''Chromium'''
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The OLECF has no distinct footer.
  
On Linux
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== Contents ==
<pre>
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/home/$USER/.config/chromium/Default/Preferences
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</pre>
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On MacOS-X
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The OLECF uses a FAT-like file system to define blocks that are assigned to the stream using multiple allocation tables.
<pre>
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It uses a directory structure to define the name of the streams.
/Users/$USER/Library/Application Support/Chromium/Default/Preferences
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</pre>
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On Windows XP
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The OLECF is used to store:
<pre>
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* [[Microsoft Office]] 97-2003 documents:
C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Chromium\User Data\Default\Preferences
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** [[Word Document (DOC)]]
</pre>
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** [[Excel Spreadsheet (XLS)]]
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** [[Powerpoint Presentation (PPT)]]
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* MSN (C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Microsoft\MSNe\msninfo.dat)
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* [[Jump Lists]]
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* StickyNotes.snt
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* [[Thumbs.db]]
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* Windows Installer (.msi) and patch file (.msp)
  
On Windows Vista and later
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== External Links ==
<pre>
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* [http://download.microsoft.com/download/0/B/E/0BE8BDD7-E5E8-422A-ABFD-4342ED7AD886/WindowsCompoundBinaryFileFormatSpecification.pdf Compound Binary File Specification], by [[Microsoft]]. Be warned this file contains at least one error: the directory entry name length is a size in bytes not in characters.
C:\Users\%USERNAME%\AppData\Local\Chromium\User Data\Default\Preferences
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* [http://msdn.microsoft.com/en-us/library/dd942138.aspx MS-CFB: Compound File Binary File Format], by [[Microsoft]]
</pre>
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* [http://www.openoffice.org/sc/compdocfileformat.pdf Microsoft Compound Document File Format], by OpenOffice.org
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* [https://googledrive.com/host/0B3fBvzttpiiSS0hEb0pjU2h6a2c/OLE%20Compound%20File%20format.pdf OLE Compound File format specification], by the [[libolecf|libolecf project]]
  
=== Plugins ===
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== Tools ==
 
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* [[libolecf]]
Information about plugins can be found under the "plugins section" of the Preferences file.
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* [http://www.mitec.cz/ssv.html MiTec Structured Storage Viewer]
 
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=== DNS Prefetching ===
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DNS is prefetched for related sites, e.g. links on the page.
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This behavior is controlled by the setting "Predict network actions to improve page load performance", which is enabled by default.
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If enabled the Preferences file contains:
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<pre>
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  "dns_prefetching": {
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      "enabled": true,
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</pre>
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If disabled the Preferences file contains:
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<pre>
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  "dns_prefetching": {
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      "enabled": false,
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</pre>
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== Start-up DNS queries ==
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When Chrome starts it queries for several non-existing hostnames that consists of a 10 random characters, E.g.
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<pre>
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ttrgoiknff.mydomain.com
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bxjhgftsyu.mydomain.com
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yokjbjiagd.mydomain.com
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</pre>
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This is used to determine if your ISP is hijacking NXDOMAIN results [http://www.google.com/support/forum/p/Chrome/thread?tid=3511015c72a7b314&hl=en].
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== Disk Cache ==
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The Google Chrome disk cache can be found in:
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On Linux
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<pre>
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/home/$USER/.config/google-chrome/Default/Application Cache/Cache/
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</pre>
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On MacOS-X
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<pre>
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/Users/$USER/Caches/Google/Chrome/Default/Cache/
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</pre>
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On Windows XP
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<pre>
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C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Google\Chrome\User Data\Cache\
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</pre>
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On Windows Vista and later
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<pre>
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C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\Default\Cache\
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</pre>
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The Chrome Cache contains different files with the following file names:
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* index
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* data_#; where # contains a decimal digit.
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* f_######; where # contains a hexadecimal digit.
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For more info see Chrome developers site [http://www.chromium.org/developers/design-documents/network-stack/disk-cache].
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== History ==
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Chrome stores the history of visited sites in a file named '''History'''. This file uses the [[SQLite database format]].
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The '''History''' file can be found in same location as the '''Preferences''' file.
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There is also '''Archived History''' that predates information in the '''History''' file.
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Note that the '''Archived History''' only contains visits.
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=== Timestamps ===
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The '''History''' file uses the different timestamps.
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==== visits.visit_time ====
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The '''visits.visit_time''' is in (the number of) microseconds since January 1, 1601 UTC
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Some Python code to do the conversion into human readable format:
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<pre>
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date_string = datetime.datetime( 1601, 1, 1 )
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            + datetime.timedelta( microseconds=timestamp )
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</pre>
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Note that this timestamp is not the same as a Windows filetime which is (the number of) 100 nanoseconds since January 1, 1601 UTC
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==== downloads.start_time ====
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The '''downloads.start_time''' is in (the number of) seconds since January 1, 1970 UTC
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Some Python code to do the conversion into human readable format:
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<pre>
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date_string = datetime.datetime( 1970, 1, 1 )
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            + datetime.timedelta( seconds=timestamp )
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</pre>
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=== Example queries ===
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Some example queries:
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To get an overview of the visited sites:
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<pre>
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SELECT datetime(((visits.visit_time/1000000)-11644473600), "unixepoch"), urls.url, urls.title FROM urls, visits WHERE urls.id = visits.url;
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</pre>
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Note that the visit_time conversion looses precision.
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To get an overview of the downloaded files:
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<pre>
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SELECT datetime(downloads.start_time, "unixepoch"), downloads.url, downloads.full_path, downloads.received_bytes, downloads.total_bytes FROM downloads;
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</pre>
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How the information of the downloaded files is stored in the database can vary per version of Chrome as of version 26:
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<pre>
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SELECT datetime(((downloads.start_time/1000000)-11644473600), "unixepoch"), downloads.target_path, downloads_url_chains.url, downloads.received_bytes, downloads.total_bytes \
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FROM downloads, downloads_url_chains WHERE downloads.id = downloads_url_chains.id;
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</pre>
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== See Also ==
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* [[SQLite database format]]
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== External Links ==
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* [http://en.wikipedia.org/wiki/Google_Chrome Wikipedia article on Google Chrome]
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* [http://www.chromium.org/user-experience/user-data-directory The Chromium Projects - User Data Directory]
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* [http://www.chromium.org/developers/design-documents/network-stack/disk-cache Chrome Disk Cache]
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* [http://www.google.com/support/forum/p/Chrome/thread?tid=3511015c72a7b314&hl=en Chrome support forum article random 10 character hostnames on startup]
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* [http://www.useragentstring.com/pages/Chrome/ Chrome User Agent strings]
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* [http://computer-forensics.sans.org/blog/2010/01/21/google-chrome-forensics/ Google Chrome Forensics] by [[Kristinn Guðjónsson]], January 21, 2010
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* [http://linuxsleuthing.blogspot.ch/2013/02/cashing-in-on-google-chrome-cache.html?m=1 Cashing in on the Google Chrome Cache], [[John Lehr]], February 24, 2013
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* [http://www.obsidianforensics.com/blog/history-index-files-removed-from-chrome/ History Index files removed from Chrome v30], by Ryan Benson, October 2, 2013
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[[Category:Applications]]
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[[Category:File Formats]]
[[Category:Web Browsers]]
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Revision as of 06:42, 11 October 2013

The Object Linking and Embedding (OLE) Compound File (CF) is used in other file formats as its underlying container file. It allows data to be stored in multiple streams.

The OLECF is also known as:

  • Compound Binary File (current name used by Microsoft)
  • Compound Document File (name used by OpenOffice)
  • OLE2 file

MIME types

Because the OLECF by itself is just a container it does not use a mime type. A mime type assigned to an OLECF refers to its contents.

File signature

The OLECF has the following file signature: hexadecimal: d0 cf 11 e0 a1 b1 1a e1

The OLECF has no distinct footer.

Contents

The OLECF uses a FAT-like file system to define blocks that are assigned to the stream using multiple allocation tables. It uses a directory structure to define the name of the streams.

The OLECF is used to store:

External Links

Tools