Difference between pages "Forensic Live CD issues" and "Google Chrome"

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== The problem ==
+
Google Chrome is a [[Web Browser|web browser]] developed by Google Inc.
  
[[Live CD|Forensic Live CDs]] are widely used during computer forensic investigations. Currently, many vendors of such Live CD distributions spread false claims that their distributions "do not touch anything", "write protect everything" and so on. Unfortunately, community-developed distributions are no exception here. Finally, it turns out that many Linux-based forensic Live CDs are not tested properly and there are no suitable test cases published.
+
== Configuration ==
 +
The Google Chrome configuration can be found in the '''Preferences''' file.
  
== Another side of the problem ==
+
On Linux
 +
<pre>
 +
/home/$USER/.config/google-chrome/Default/Preferences
 +
</pre>
  
Another side of the problem of insufficient testing of forensic Live CDs is that many users do not know what happens "under the hood" of the provided operating system and cannot adequately test them.
+
On MacOS-X
 +
<pre>
 +
/Users/$USER/Library/Application Support/Google/Chrome/Default/Preferences
 +
</pre>
  
=== Example ===
+
On Windows XP
 +
<pre>
 +
C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Google\Chrome\User Data\Default\Preferences
 +
</pre>
  
For example, [http://forensiccop.blogspot.com/2009/10/forensic-cop-journal-13-2009.html ''Forensic Cop Journal'' (Volume 1(3), Oct 2009)] describes a test case when an Ext3 file system was mounted using "-o ro" mount flag as a way to write protect the data. The article says that all tests were successful (i.e. no data modification was found after unmounting the file system), but it is known that damaged (i.e not properly unmounted) Ext3 file systems cannot be write protected using only "-o ro" mount flags (write access will be enabled during file system recovery).
+
On Windows Vista and later
 +
<pre>
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\Default\Preferences
 +
</pre>
  
And the question is: will many users test damaged Ext3 file system (together with testing the clean one) when validating their favourite forensic Live CD distribution? My answer is "no", because many users are unaware of such traits.
+
Or for '''Chrome SxS''' (Chrome side-by-side)
  
== Problems ==
+
<pre>
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chrome SxS\User Data\Default\Preferences
 +
</pre>
  
Each problem is followed by a list of distributions affected (currently this list is not up-to-date).
+
Or for '''Chromium'''
  
=== Journaling file system updates ===
+
On Linux
 +
<pre>
 +
/home/$USER/.config/chromium/Default/Preferences
 +
</pre>
  
When mounting (and unmounting) several journaling file systems with only "-o ro" mount flag a different number of data writes may occur. Here is a list of such file systems:
+
On MacOS-X
 +
<pre>
 +
/Users/$USER/Library/Application Support/Chromium/Default/Preferences
 +
</pre>
  
{| class="wikitable" border="1"
+
On Windows XP
|-
+
<pre>
!  File system
+
C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Chromium\User Data\Default\Preferences
!  When data writes happen
+
</pre>
!  Notes
+
|-
+
|  Ext3
+
|  File system requires journal recovery
+
|  To disable recovery: use "noload" flag, or use "ro,loop" flags, or use "ext2" file system type
+
|-
+
|  Ext4
+
|  File system requires journal recovery
+
|  To disable recovery: use "noload" flag, or use "ro,loop" flags, or use "ext2" file system type
+
|-
+
|  ReiserFS
+
|  File system has unfinished transactions
+
|  "nolog" flag does not work (see ''man mount''). To disable journal updates: use "ro,loop" flags
+
|-
+
|  XFS
+
|  Always (when unmounting)
+
|  "norecovery" flag does not help (fixed in recent 2.6 kernels). To disable data writes: use "ro,loop" flags.
+
|}
+
  
Incorrect mount flags can be used to mount file systems on evidentiary media during the boot process or during the file system preview process. As described above, this may result in data writes to evidentiary media. For example, several Ubuntu-based forensic Live CD distributions mount and recover damaged Ext3/4 file systems on fixed media (e.g. hard drives) during execution of [http://en.wikipedia.org/wiki/Initrd ''initrd''] scripts (these scripts mount every supported file system type on every supported media type using only "-o ro" flag in order to find a root file system image).
+
On Windows Vista and later
 +
<pre>
 +
C:\Users\%USERNAME%\AppData\Local\Chromium\User Data\Default\Preferences
 +
</pre>
  
[[Image:ext3 recovery.png|thumb|right|[[Helix3]]: damaged Ext3 recovery during the boot]]
+
=== Plugins ===
  
List of distributions that recover Ext3 (and sometimes Ext4) file systems during the boot:
+
Information about plugins can be found under the "plugins section" of the Preferences file.
  
{| class="wikitable" border="1"
+
=== DNS Prefetching ===
|-
+
!  Distribution
+
!  Version
+
|-
+
|  Helix3
+
|  2009R1
+
|-
+
|  SMART Linux (Ubuntu)
+
|  2010-01-20
+
|-
+
|  FCCU GNU/Linux Forensic Boot CD
+
|  12.1
+
|-
+
|  SPADA
+
|  4
+
|-
+
|  DEFT Linux
+
|  7
+
|}
+
  
=== Orphan inodes deletion ===
+
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.
  
When mounting Ext3/4 file systems all orphan inodes are removed, even if "-o ro" mount flag was specified. Currently, there is no specific mount flag to disable orphan inodes deletion. The only solution here is to use "-o ro,loop" flags.
+
If enabled the Preferences file contains:
 +
<pre>
 +
  "dns_prefetching": {
 +
      "enabled": true,
 +
</pre>
  
=== Root file system spoofing ===
+
If disabled the Preferences file contains:
 +
<pre>
 +
  "dns_prefetching": {
 +
      "enabled": false,
 +
</pre>
  
''See also: [[Early userspace | early userspace]]''
+
== Start-up DNS queries ==
  
Most Ubuntu-based forensic Live CD distributions use Casper (a set of scripts used to complete initialization process during early stage of boot). Casper is responsible for searching for a root file system (typically, an image of live environment) on all supported devices (because a bootloader does not pass any information about device used for booting to the kernel), mounting it and executing ''/sbin/init'' program on a mounted root file system that will continue the boot process. Unfortunately, Casper was not designed to meet computer forensics requirements and is responsible for damaged Ext3/4 file systems recovery during the boot (see above) and root file system spoofing.
+
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>
  
[[Image:Grml.png|thumb|right|[[grml]] mounted root file system from the [[hard drive]]]]
+
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].
  
Currently, Casper may select fake root file system image on evidentiary media (e.g. [[Hard Drive|HDD]]), because there are no authenticity checks performed (except optional UUID check for a possible live file system), and this fake root file system image may be used to execute malicious code during the boot with root privileges. Knoppix-based forensic Live CD distributions are vulnerable to the same attack.
+
== Disk Cache ==
 +
Google Chrome uses multiple caches, from [http://src.chromium.org/viewvc/chrome/trunk/src/net/base/cache_type.h?view=markup]:
 +
<pre>
 +
// The types of caches that can be created.
 +
enum CacheType {
 +
    DISK_CACHE,  // Disk is used as the backing storage.
 +
    MEMORY_CACHE,  // Data is stored only in memory.
 +
    MEDIA_CACHE,  // Optimized to handle media files.
 +
    APP_CACHE,  // Backing store for an AppCache.
 +
    SHADER_CACHE, // Backing store for the GL shader cache.
 +
    PNACL_CACHE, // Backing store the PNaCl translation cache
 +
};
 +
</pre>
  
List of Ubuntu-based distributions that allow root file system spoofing:
+
<b>Note that $PROFILE (or %PROFILE%) the paths below is the profile dependent subdirectory which is normally Default but also could be Profile1, Profile2, etc.</b>
  
{| class="wikitable" border="1"
+
The Google Chrome disk cache can be found in:
|-
+
!  Distribution
+
!  Version
+
|-
+
|  Helix3
+
|  2009R1
+
|-
+
|  Helix3 Pro
+
|  2009R3
+
|-
+
|  CAINE
+
|  1.5
+
|-
+
|  DEFT Linux
+
|  5
+
|-
+
|  Raptor
+
|  2.0
+
|-
+
|  BackTrack
+
|  4
+
|-
+
|  SMART Linux (Ubuntu)
+
|  2010-01-20
+
|-
+
|  FCCU GNU/Linux Forensic Boot CD
+
|  12.1
+
|}
+
  
Vulnerable Knoppix-based distributions include: SPADA, LinEn Boot CD, BitFlare.
+
On Linux
  
[http://anti-forensics.ru/ Anti-Forensics.Ru project] [http://digitalcorpora.org/corp/images/aor/ released several ISO 9660 images] used to test various Linux Live CD distributions for root file system spoofing (description for all images is [http://anti-forensics.ru/casper/ here]).
+
<pre>
 +
/home/$USER/.cache/chromium/$PROFILE/Cache/
 +
/home/$USER/.cache/google-chrome/$PROFILE/Cache/
 +
/home/$USER/.config/chromium/$PROFILE/Cache/
 +
/home/$USER/.config/google-chrome/$PROFILE/Cache/
 +
</pre>
  
=== Swap space activation ===
+
<pre>
 +
/home/$USER/.cache/chromium/$PROFILE/Media Cache/
 +
/home/$USER/.cache/google-chrome/$PROFILE/Media Cache/
 +
/home/$USER/.config/chromium/$PROFILE/Media Cache/
 +
/home/$USER/.config/google-chrome/$PROFILE/Media Cache/
 +
</pre>
  
''Feel free to add information about swap space activation during the boot in some distributions''
+
<pre>
 +
/home/$USER/.config/chromium/$PROFILE/Application Cache/Cache/
 +
/home/$USER/.config/google-chrome/$PROFILE/Application Cache/Cache/
 +
</pre>
  
=== Incorrect mount policy ===
+
<pre>
 +
/home/$USER/.config/chromium/$PROFILE/GPUCache/
 +
/home/$USER/.config/google-chrome/$PROFILE/GPUCache/
 +
</pre>
  
==== rebuildfstab and scanpartitions scripts ====
+
<pre>
 +
/home/$USER/.cache/chromium/PnaclTranslationCache/
 +
/home/$USER/.cache/google-chrome/PnaclTranslationCache/
 +
</pre>
  
Several forensic Linux Live CD distributions (Helix3 2009R1, Helix3 Pro 2009R3, old versions of CAINE, old versions of grml) use rebuildfstab and scanpartition scripts to create entries for attached devices in ''/etc/fstab''. Some versions of these scripts use wrong wildcards while searching for available block devices (''/dev/?d?'' instead of ''/dev/?d*''), this results in missing several "exotic" devices (like /dev/sdad, /dev/sdad1, etc) and in data writes when mounting them (because fstab lacks of read-only mount options for these devices).
+
On MacOS-X
 +
<pre>
 +
/Users/$USER/Library/Caches/Chromium/$PROFILE/Cache
 +
/Users/$USER/Library/Caches/Google/Chrome/$PROFILE/Cache
 +
</pre>
  
=== Incorrect write-blocking approach ===
+
<b>TODO confirm the following paths</b>
 +
<pre>
 +
/Users/$USER/Caches/Chromium/$PROFILE/Cache/
 +
/Users/$USER/Caches/Google/Chrome/$PROFILE/Cache/
 +
</pre>
  
Some forensic Linux Live CD distributions rely on [[hdparm]] and [[blockdev]] programs to mount file systems in read-only mode (by setting the underlying block device to read-only mode). Unfortunately, setting the block device to read-only mode does not guarantee that [http://archives.free.net.ph/message/20090721.105120.99250e3f.en.html no write commands will be passed to the drive].
+
<pre>
 +
/Users/$USER/Library/Caches/Chromium/$PROFILE/Media Cache
 +
/Users/$USER/Library/Caches/Google/Chrome/$PROFILE/Media Cache
 +
</pre>
  
== External links ==
+
<pre>
 +
/Users/$USER/Library/Application Support/Chromium/$PROFILE/Application Cache/Cache/
 +
/Users/$USER/Library/Application Support/Google/Chrome/$PROFILE/Application Cache/Cache/
 +
</pre>
  
* [http://www.computer-forensics-lab.org/pdf/Linux_for_computer_forensic_investigators_2.pdf Linux for computer forensic investigators: problems of booting trusted operating system]
+
<pre>
* [http://www.computer-forensics-lab.org/pdf/Linux_for_computer_forensic_investigators.pdf Linux for computer forensic investigators: «pitfalls» of mounting file systems]
+
/Users/$USER/Library/Application Support/Chromium/$PROFILE/GPUCache/
 +
/Users/$USER/Library/Application Support/Google/Chrome/$PROFILE/GPUCache/
 +
</pre>
  
[[Category:Live CD]]
+
<pre>
 +
/Users/$USER/Library/Caches/Chromium/PnaclTranslationCache/
 +
/Users/$USER/Library/Caches/Google/Chrome/PnaclTranslationCache/
 +
</pre>
 +
 
 +
On Windows XP
 +
 
 +
<b>TODO confirm the following paths</b>
 +
<pre>
 +
C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Chromium\User Data\Cache\
 +
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\Chromium\%PROFILE%\Cache\
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\Cache\
 +
</pre>
 +
 
 +
<pre>
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chromium\%PROFILE%\Application Cache\Cache\
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\Application Cache\Cache\
 +
</pre>
 +
 
 +
<pre>
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chromium\%PROFILE%\Media Cache\
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\Media Cache\
 +
</pre>
 +
 
 +
<pre>
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chromium\%PROFILE%\GPUCache\
 +
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\GPUCache\
 +
</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 Disk Cache Format]].
 +
 
 +
== 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>
 +
 
 +
== Cookies ==
 +
Chrome stores the cookies in a file named '''Cookies'''. This file uses the [[SQLite database format]].
 +
 
 +
=== Extension Cookies ===
 +
Chrome stores the cookies used by extensions in a file named '''Extension Cookies'''. This file uses the [[SQLite database format]].
 +
 
 +
<pre>
 +
SELECT datetime(((cookies.creation_utc/1000000)-11644473600), "unixepoch"), cookies.host_key, cookies.name, cookies.value, cookies.path, \
 +
datetime(((cookies.expires_utc/1000000)-11644473600), "unixepoch"), cookies.secure, cookies.httponly, datetime(((cookies.last_access_utc/1000000)-11644473600), "unixepoch"), \
 +
cookies.has_expires, cookies.persistent, cookies.priority FROM cookies;
 +
</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
 +
* [https://hindsight-internet-history.googlecode.com/files/Evolution_of_Chrome_Databases.png Evolution of Chrome Databases], by Ryan Benson, November 12, 2013
 +
 
 +
== Tools ==
 +
=== Open Source ===
 +
* [https://code.google.com/p/hindsight-internet-history/ hindsight-internet-history]
 +
 
 +
[[Category:Applications]]
 +
[[Category:Web Browsers]]

Revision as of 04:42, 22 June 2014

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 Chrome SxS (Chrome side-by-side)

C:\Users\%USERNAME%\AppData\Local\Google\Chrome SxS\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

Google Chrome uses multiple caches, from [2]:

// The types of caches that can be created.
enum CacheType {
    DISK_CACHE,  // Disk is used as the backing storage.
    MEMORY_CACHE,  // Data is stored only in memory.
    MEDIA_CACHE,  // Optimized to handle media files.
    APP_CACHE,  // Backing store for an AppCache.
    SHADER_CACHE, // Backing store for the GL shader cache.
    PNACL_CACHE, // Backing store the PNaCl translation cache
};

Note that $PROFILE (or %PROFILE%) the paths below is the profile dependent subdirectory which is normally Default but also could be Profile1, Profile2, etc.

The Google Chrome disk cache can be found in:

On Linux

/home/$USER/.cache/chromium/$PROFILE/Cache/
/home/$USER/.cache/google-chrome/$PROFILE/Cache/
/home/$USER/.config/chromium/$PROFILE/Cache/
/home/$USER/.config/google-chrome/$PROFILE/Cache/
/home/$USER/.cache/chromium/$PROFILE/Media Cache/
/home/$USER/.cache/google-chrome/$PROFILE/Media Cache/
/home/$USER/.config/chromium/$PROFILE/Media Cache/
/home/$USER/.config/google-chrome/$PROFILE/Media Cache/
/home/$USER/.config/chromium/$PROFILE/Application Cache/Cache/
/home/$USER/.config/google-chrome/$PROFILE/Application Cache/Cache/
/home/$USER/.config/chromium/$PROFILE/GPUCache/
/home/$USER/.config/google-chrome/$PROFILE/GPUCache/
/home/$USER/.cache/chromium/PnaclTranslationCache/
/home/$USER/.cache/google-chrome/PnaclTranslationCache/

On MacOS-X

/Users/$USER/Library/Caches/Chromium/$PROFILE/Cache
/Users/$USER/Library/Caches/Google/Chrome/$PROFILE/Cache

TODO confirm the following paths

/Users/$USER/Caches/Chromium/$PROFILE/Cache/
/Users/$USER/Caches/Google/Chrome/$PROFILE/Cache/
/Users/$USER/Library/Caches/Chromium/$PROFILE/Media Cache
/Users/$USER/Library/Caches/Google/Chrome/$PROFILE/Media Cache
/Users/$USER/Library/Application Support/Chromium/$PROFILE/Application Cache/Cache/
/Users/$USER/Library/Application Support/Google/Chrome/$PROFILE/Application Cache/Cache/
/Users/$USER/Library/Application Support/Chromium/$PROFILE/GPUCache/
/Users/$USER/Library/Application Support/Google/Chrome/$PROFILE/GPUCache/
/Users/$USER/Library/Caches/Chromium/PnaclTranslationCache/
/Users/$USER/Library/Caches/Google/Chrome/PnaclTranslationCache/

On Windows XP

TODO confirm the following paths

C:\Documents and Settings\%USERNAME%\Local Settings\Application Data\Chromium\User Data\Cache\
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\Chromium\%PROFILE%\Cache\
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\Cache\
C:\Users\%USERNAME%\AppData\Local\Google\Chromium\%PROFILE%\Application Cache\Cache\
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\Application Cache\Cache\
C:\Users\%USERNAME%\AppData\Local\Google\Chromium\%PROFILE%\Media Cache\
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\Media Cache\
C:\Users\%USERNAME%\AppData\Local\Google\Chromium\%PROFILE%\GPUCache\
C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\%PROFILE%\GPUCache\

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 Disk Cache Format.

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;

Cookies

Chrome stores the cookies in a file named Cookies. This file uses the SQLite database format.

Extension Cookies

Chrome stores the cookies used by extensions in a file named Extension Cookies. This file uses the SQLite database format.

SELECT datetime(((cookies.creation_utc/1000000)-11644473600), "unixepoch"), cookies.host_key, cookies.name, cookies.value, cookies.path, \
datetime(((cookies.expires_utc/1000000)-11644473600), "unixepoch"), cookies.secure, cookies.httponly, datetime(((cookies.last_access_utc/1000000)-11644473600), "unixepoch"), \
cookies.has_expires, cookies.persistent, cookies.priority FROM cookies;

See Also

External Links

Tools

Open Source