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

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

Revision as of 14:47, 10 October 2013

Google Chrome is a web browser developed by Google Inc.

Contents

Configuration

The Google Chrome configuration can be found in the Preferences file.

On Linux

/home/$USER/.config/google-chrome/Default/Preferences

On MacOS-X

/Users/$USER/Library/Application Support/Google/Chrome/Default/Preferences

On Windows XP

C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Google\Chrome\User Data\Default\Preferences

On Windows Vista and later

C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\Default\Preferences

Or for Chromium

On Linux

/home/$USER/.config/chromium/Default/Preferences

On MacOS-X

/Users/$USER/Library/Application Support/Chromium/Default/Preferences

On Windows XP

C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Chromium\User Data\Default\Preferences

On Windows Vista and later

C:\Users\%USERNAME%\AppData\Local\Chromium\User Data\Default\Preferences

Plugins

Information about plugins can be found under the "plugins section" of the Preferences file.

DNS Prefetching

DNS is prefetched for related sites, e.g. links on the page. This behavior is controlled by the setting "Predict network actions to improve page load performance", which is enabled by default.

If enabled the Preferences file contains:

   "dns_prefetching": {
      "enabled": true,

If disabled the Preferences file contains:

   "dns_prefetching": {
      "enabled": false,

Start-up DNS queries

When Chrome starts it queries for several non-existing hostnames that consists of a 10 random characters, E.g.

ttrgoiknff.mydomain.com
bxjhgftsyu.mydomain.com
yokjbjiagd.mydomain.com

This is used to determine if your ISP is hijacking NXDOMAIN results [1].

Disk Cache

The Google Chrome disk cache can be found in:

On Linux

/home/$USER/.config/google-chrome/Default/Application Cache/Cache/

On MacOS-X

/Users/$USER/Caches/Google/Chrome/Default/Cache/

On Windows XP

C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Google\Chrome\User Data\Cache\

On Windows Vista and later

C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\Default\Cache\

The Chrome Cache contains different files with the following file names:

  • index
  • data_#; where # contains a decimal digit.
  • f_######; where # contains a hexadecimal digit.

For more info see Chrome developers site [2].

History

Chrome stores the history of visited sites in a file named History. This file uses the SQLite database format.

The History file can be found in same location as the Preferences file.

There is also Archived History that predates information in the History file. Note that the Archived History only contains visits.

Timestamps

The History file uses the different timestamps.

visits.visit_time

The visits.visit_time is in (the number of) microseconds since January 1, 1601 UTC

Some Python code to do the conversion into human readable format:

date_string = datetime.datetime( 1601, 1, 1 )
            + datetime.timedelta( microseconds=timestamp )

Note that this timestamp is not the same as a Windows filetime which is (the number of) 100 nanoseconds since January 1, 1601 UTC

downloads.start_time

The downloads.start_time is in (the number of) seconds since January 1, 1970 UTC

Some Python code to do the conversion into human readable format:

date_string = datetime.datetime( 1970, 1, 1 )
            + datetime.timedelta( seconds=timestamp )

Example queries

Some example queries:

To get an overview of the visited sites:

SELECT datetime(((visits.visit_time/1000000)-11644473600), "unixepoch"), urls.url, urls.title FROM urls, visits WHERE urls.id = visits.url;

Note that the visit_time conversion looses precision.

To get an overview of the downloaded files:

SELECT datetime(downloads.start_time, "unixepoch"), downloads.url, downloads.full_path, downloads.received_bytes, downloads.total_bytes FROM downloads;

How the information of the downloaded files is stored in the database can vary per version of Chrome as of version 26:

SELECT datetime(((downloads.start_time/1000000)-11644473600), "unixepoch"), downloads.target_path, downloads_url_chains.url, downloads.received_bytes, downloads.total_bytes \
FROM downloads, downloads_url_chains WHERE downloads.id = downloads_url_chains.id;

See Also

External Links