Difference between pages "Forensic Live CD issues" and "Plaso"

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== The problem ==
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{{Infobox_Software |
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  name = plaso |
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  maintainer = [[Kristinn Gudjonsson]], [[Joachim Metz]] |
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  os = [[Linux]], [[Mac OS X]], [[Windows]] |
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  genre = {{Analysis}} |
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  license = {{APL}} |
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  website = [https://code.google.com/p/plaso/ code.google.com/p/plaso/] |
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}}
  
[[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.
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Plaso (plaso langar að safna öllu) is the Python based back-end engine used by tools such as log2timeline for automatic creation of a super timelines. The goal of log2timeline (and thus plaso) is to provide a single tool that can parse various log files and forensic artifacts from computers and related systems, such as network equipment to produce a single correlated timeline. This timeline can then be easily analysed by forensic investigators/analysts, speeding up investigations by correlating the vast amount of information found on an average computer system. Plaso is intended to be applied for creating super timelines but also supports creating [http://blog.kiddaland.net/2013/02/targeted-timelines-part-i.html targeted timelines].
  
== Another side of the problem ==
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The Plaso project site also provides [[4n6time]], formerly "l2t_Review", which is a cross-platform forensic tool for timeline creation and review by [[David Nides]].
  
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.
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== Supported Formats ==
  
=== Example ===
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=== Storage Media Image File Formats ===
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Storage Medis Image File Format support is provided by [[dfvfs]].
  
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).
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=== Volume System Formats ===
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Volume System Format support is provided by [[dfvfs]].
  
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.
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=== File System Formats ===
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File System Format support is provided by [[dfvfs]].
  
== Problems ==
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=== File Formats ===
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* [[Property list (plist)|Binary property list (plist) format]] using [[binplist]]
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* [[Extensible Storage Engine (ESE) Database File (EDB) format]]using [[libesedb]]
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* [[Internet Explorer History File Format]] (also known as MSIE 4 - 9 Cache Files or index.dat) using [[libmsiecf]]
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* [[OLE Compound File]] using [[libolecf]]
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* [[Windows Event Log (EVT)]] using [[libevt]]
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* [[Windows NT Registry File (REGF)]] using [[libregf]]
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* [[LNK|Windows Shortcut File (LNK) format]] using [[liblnk]]
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* [[Windows XML Event Log (EVTX)]] using [[libevtx]]
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* Syslog
  
Each problem is followed by a list of distributions affected (currently this list is not up-to-date).
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<b>TODO expand this list</b>
  
=== Journaling file system updates ===
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== History ==
 +
Plaso is a Python-based rewrite of the Perl-based [[log2timeline]] initially created by [[Kristinn Gudjonsson]]. Plaso builds upon the [[SleuthKit]], [[libyal]] and other projects.
  
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:
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== See Also ==
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* [[dfvfs]]
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* [[log2timeline]]
  
{| class="wikitable" border="1"
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== External Links ==
|-
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* [https://code.google.com/p/plaso/ Project site]
!  File system
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* [https://sites.google.com/a/kiddaland.net/plaso/home Project documentation]
!  When data writes happen
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* [http://blog.kiddaland.net/ Project blog]
!  Notes
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* [https://sites.google.com/a/kiddaland.net/plaso/usage/4n6time 4n6time]
|-
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|  Ext3
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|  File system requires journal recovery
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|  To disable recovery: use "noload" flag, or use "ro,loop" flags, or use "ext2" file system type
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|-
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|  Ext4
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|  File system requires journal recovery
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|  To disable recovery: use "noload" flag, or use "ro,loop" flags, or use "ext2" file system type
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|-
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|  ReiserFS
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|  File system has unfinished transactions
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|  "nolog" flag does not work (see ''man mount''). To disable journal updates: use "ro,loop" flags
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|-
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|  XFS
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|  Always (when unmounting)
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|  "norecovery" flag does not help (fixed in recent 2.6 kernels). To disable data writes: use "ro,loop" flags.
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|}
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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).
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[[Image:ext3 recovery.png|thumb|right|[[Helix3]]: damaged Ext3 recovery during the boot]]
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List of distributions that recover Ext3 (and sometimes Ext4) file systems during the boot:
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{| class="wikitable" border="1"
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|-
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!  Distribution
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!  Version
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|-
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|  Helix3
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|  2009R1
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|-
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|  SMART Linux (Ubuntu)
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|  2010-01-20
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|-
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|  FCCU GNU/Linux Forensic Boot CD
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|  12.1
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|-
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|  SPADA
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|  4
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|-
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|  DEFT Linux
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|  7
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|}
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=== Orphan inodes deletion ===
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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.
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=== Root file system spoofing ===
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''See also: [[Early userspace | early userspace]]''
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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.
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[[Image:Grml.png|thumb|right|[[grml]] mounted root file system from the [[hard drive]]]]
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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.
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List of Ubuntu-based distributions that allow root file system spoofing:
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{| class="wikitable" border="1"
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|-
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!  Distribution
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!  Version
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|-
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|  Helix3
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|  2009R1
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|-
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|  Helix3 Pro
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|  2009R3
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|-
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|  CAINE
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|  1.5
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|-
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|  DEFT Linux
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|  5
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|-
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|  Raptor
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|  2.0
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|-
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|  BackTrack
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|  4
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|-
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|  SMART Linux (Ubuntu)
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|  2010-01-20
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|-
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|  FCCU GNU/Linux Forensic Boot CD
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|  12.1
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|}
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Vulnerable Knoppix-based distributions include: SPADA, LinEn Boot CD, BitFlare.
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[http://anti-forensics.ru/ Anti-Forensics.Ru project] [http://digitalcorpora.org/corp/aor/drives/ 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]).
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=== Swap space activation ===
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''Feel free to add information about swap space activation during the boot in some distributions''
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=== Incorrect mount policy ===
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==== rebuildfstab and scanpartitions scripts ====
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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).
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=== Incorrect write-blocking approach ===
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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].
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== External links ==
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* [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]
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* [http://www.computer-forensics-lab.org/pdf/Linux_for_computer_forensic_investigators.pdf Linux for computer forensic investigators: «pitfalls» of mounting file systems]
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[[Category:Live CD]]
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Revision as of 03:21, 3 June 2014

plaso
Maintainer: Kristinn Gudjonsson, Joachim Metz
OS: Linux, Mac OS X, Windows
Genre: Analysis
License: APL
Website: code.google.com/p/plaso/

Plaso (plaso langar að safna öllu) is the Python based back-end engine used by tools such as log2timeline for automatic creation of a super timelines. The goal of log2timeline (and thus plaso) is to provide a single tool that can parse various log files and forensic artifacts from computers and related systems, such as network equipment to produce a single correlated timeline. This timeline can then be easily analysed by forensic investigators/analysts, speeding up investigations by correlating the vast amount of information found on an average computer system. Plaso is intended to be applied for creating super timelines but also supports creating targeted timelines.

The Plaso project site also provides 4n6time, formerly "l2t_Review", which is a cross-platform forensic tool for timeline creation and review by David Nides.

Supported Formats

Storage Media Image File Formats

Storage Medis Image File Format support is provided by dfvfs.

Volume System Formats

Volume System Format support is provided by dfvfs.

File System Formats

File System Format support is provided by dfvfs.

File Formats

TODO expand this list

History

Plaso is a Python-based rewrite of the Perl-based log2timeline initially created by Kristinn Gudjonsson. Plaso builds upon the SleuthKit, libyal and other projects.

See Also

External Links