Difference between pages "File Systems" and "Google Chrome"

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(Cryptographic File Systems)
 
(Example queries)
 
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= Conventional File Systems =
+
Google Chrome is a [[Web Browser|web browser]] developed by Google Inc.
  
; ffs
+
== Configuration ==
: The Fast File System, a variant of ufs that is faster and supports symbolic links.
+
The Google Chrome configuration can be found in the '''Preferences''' file.
  
; ext2fs, ext3
+
On Linux
: ext2fs was introduced with Linux. ext3 is a journaled version of ext2 which allows for speedy disk recovery after a crash.
+
<pre>
 +
/home/$USER/.config/google-chrome/Default/Preferences
 +
</pre>
  
; FAT
+
On MacOS-X
: Originally used by MSDOS. Includes FAT12 (for floppy disks), FAT16 and FAT32
+
<pre>
 +
/Users/$USER/Library/Application Support/Google/Chrome/Default/Preferences
 +
</pre>
  
; NTFS
+
On Windows XP
: The New Technology File System, introduced by Microsoft with Windows NT 4.0. Now used on XP.
+
<pre>
 +
C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Google\Chrome\User Data\Default\Preferences
 +
</pre>
  
; ufs
+
On Windows Vista and later
: The Unix File System, introduced with Unix.
+
<pre>
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\Default\Preferences
 +
</pre>
  
;
+
Or for '''Chromium'''
  
 +
On Linux
 +
<pre>
 +
/home/$USER/.config/chromium/Default/Preferences
 +
</pre>
  
= Cryptographic File Systems =
+
On MacOS-X
Cryptographic file systems encrypt information before it is stored on the media. Some of these file systems store encrypted files directly. Others are better thought of as device drivers, which are then used to store some of the file systems discussed above.
+
<pre>
 +
/Users/$USER/Library/Application Support/Chromium/Default/Preferences
 +
</pre>
  
; Apple's File Vault
+
On Windows XP
: A clever user interface to Apple's encrypted disk images. Uses the ".sparseimage" extension on disk files.
+
<pre>
 +
C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Chromium\User Data\Default\Preferences
 +
</pre>
  
; CFS - Matt Blaze's Cryptographic File System for Unix
+
On Windows Vista and later
: [http://http://www.crypto.com/papers/cfskey.pdf|Key Management in an Encrypting File System], Matt Blaze, USENIX Summer 1994 Technical Conference, Boston, MA, June 1994.
+
<pre>
: [http://http://www.crypto.com/papers/cfs.pdf|A Cryptographic File System for Unix], Matt Blaze, Proceedings of the First ACM Conference on Computer and Communications Security, Fairfax, VA, November 1993.
+
C:\Users\%USERNAME%\AppData\Local\Chromium\User Data\Default\Preferences
 +
</pre>
  
; Transparent Cryptographic File System
+
=== Plugins ===
: http://www.tcfs.it/
+
  
 +
Information about plugins can be found under the "plugins section" of the Preferences file.
  
== Full Disk Encryption ==
+
=== DNS Prefetching ===
; Seagate FDE
+
: http://www.seagate.com/docs/pdf/marketing/PO-Momentus-FDE.pdf
+
  
; Network Appliance
+
DNS is prefetched for related sites, e.g. links on the page.
: http://www.netapp.com/ftp/decru-fileshredding.pdf
+
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 a newer variant of the previous query is:
 +
<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://computer-forensics.sans.org/blog/2010/01/21/google-chrome-forensics/ Google Chrome Forensics] by [[Kristinn Guðjónsson]]
 +
* [http://www.useragentstring.com/pages/Chrome/ Chrome User Agent strings]
 +
* [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
 +
 
 +
[[Category:Applications]]
 +
[[Category:Web Browsers]]

Revision as of 01:51, 20 April 2013

Google Chrome is a web browser developed by Google Inc.

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 a newer variant of the previous query is:

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