Difference between pages "Paraben SIM Card Seizure" and "Forensic Live CD issues"

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m (Journaling file systems updates)
 
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Paraben has acquired SIMCon and has integrated it into SIM Card Seizure and Device Seizure. Recover deleted sms/text messages and perform comprehensive analysis of SIM card data. SIM Card Seizure takes the SIM Card acquisition and analysis components from Paraben's Device Seizure and puts it into a specialized SIM Card forensic acquisition and analysis tool. SIM Card Seizure includes the software as well as a Forensic SIM Card Reader. If you already have Device Seizure & the Device Seizure Toolbox, there's no need for you to get SIM Card Seizure as well because they contain the components to perform a forensic SIM Card acquisition and analysis. This tool is for the investigator who only wants to acquire SIM Cards and does not want to perform forensic exams of all cell phone data.
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== The problem ==
  
SIM Card Seizure has unicode support to read multiple languages such as Arabic, Chinese, & Russian: Features:
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[[Tools#Forensics_Live_CDs | Forensic Linux Live CD distributions]] 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. Community-developed distributions are not exception here, unfortunately. Finally, it turns out that many forensic Linux Live CD distributions are not tested properly and there are no suitable test cases developed.
  
    * Forensic SIM Card Reader Included
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== Another side of the problem ==
    * Calculates MD5 & SHA1 Hash Values
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    * Search Function
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    * Recovers Deleted SMS Data*
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    * Bookmarking Options
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    * Report Creation Wizard
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    * Save Workspaces for Further Review
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    * Time Stamps Calculate GMT Offset
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    * Access to Paraben's Forum
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    * Access to Paraben's 24 Hour Support
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Data Acquired from SIM Cards
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Another side of the problem of insufficient testing of forensic Live CD distributions is that many users do not know what happens "under the hood" of such distributions and cannot adequately test them.
  
    * Phase Phase ID
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=== Example ===
    * SST SIM Service table
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    * ICCID Serial Number
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    * LP Preferred languages variable
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    * SPN Service Provider name
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    * MSISDN Subscriber phone number
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    * AND Short Dial Number
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    * FDN Fixed Numbers
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    * LND Last Dialed numbers
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    * EXT1 Dialing Extension
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    * EXT2 Dialing Extension
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    * GID1 Groups
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    * GID2 Groups
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    * SMS Text Messages
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    * SMSP Text Message parameters
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    * SMSS Text message status
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    * CBMI Preferred network messages
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    * PUCT Charges per unit
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    * ACM Charge counter
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    * ACMmax Charge limit
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    * HPLMNSP HPLMN search period
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    * PLMNsel PLMN selector
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    * FPLMN Forbidden PLMNs
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    * CCP Capability configuration parameter
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    * ACC Access control class
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    * IMSI IMSI
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    * LOCI Location information
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    * BCCH Broadcast control channels
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    * Kc Ciphering key
+
  
SIM Card Seizure also acquires the whole catalog system with data in a tree-view presentation. Additionally, it can recover some deleted SMS data by analysis of unallocated space.
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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).
 +
 
 +
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.
 +
 
 +
== Problems ==
 +
 
 +
Here is a list of common problems of forensic Linux Live CD distributions that can be used by developers and users for testing purposes. Each problem is followed by an up to date list of distributions affected.
 +
 
 +
=== Journaling file systems updates ===
 +
 
 +
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:
 +
 
 +
{| class="wikitable" border="1"
 +
|-
 +
!  File system
 +
!  When data writes happen
 +
!  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
 +
|  "norecovery" flag does not help. To disable data writes: use "ro,loop" flags. The bug was fixed in recent 2.6 kernels.
 +
|}
 +
 
 +
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).
 +
 
 +
[[Image:ext3 recovery.png|thumb|right|[[Helix3]]: damaged Ext3 recovery during the boot]]
 +
 
 +
List of distributions that recover Ext3 (and sometimes Ext4) file systems during the boot:
 +
 
 +
{| class="wikitable" border="1"
 +
|-
 +
!  Distribution
 +
!  Version
 +
|-
 +
|  Helix3
 +
|  2009R1
 +
|-
 +
|  SMART Linux (Ubuntu)
 +
|  2010-01-20
 +
|-
 +
|  FCCU GNU/Linux Forensic Boot CD
 +
|  12.1
 +
|-
 +
|  SPADA
 +
|  4
 +
|}
 +
 
 +
=== Root file system spoofing ===
 +
 
 +
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.
 +
 
 +
[[Image:Grml.png|thumb|right|[[grml]] mounted root file system from the [[hard drive]]]]
 +
 
 +
Currently, Casper may select fake root file system image on evidentiary media (e.g. [[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.
 +
 
 +
List of Ubuntu-based distributions that allow root file system spoofing:
 +
 
 +
{| class="wikitable" border="1"
 +
|-
 +
!  Distribution
 +
!  Version
 +
!  Notes
 +
|-
 +
|  Helix3
 +
|  2009R1
 +
|
 +
|-
 +
|  Helix3 Pro
 +
|  2009R3
 +
|
 +
|-
 +
|  CAINE
 +
|  1.5
 +
|
 +
|-
 +
|  DEFT Linux
 +
|  5
 +
|
 +
|-
 +
|  Raptor
 +
|  20091026
 +
|
 +
|-
 +
|  grml
 +
|  2009.10
 +
|  Actually, [[grml]] uses live-initramfs scripts (Casper fork)
 +
|-
 +
|  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.
 +
 
 +
=== Swap space activation ===
 +
 
 +
=== Incorrect mount policy ===
 +
 
 +
==== HAL ====
 +
 
 +
==== rebuildfstab and scanpartition scripts ====
 +
 
 +
=== Incorrect write-blocking approach ===
 +
 
 +
== See also ==
 +
 
 +
* [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]
 +
* [http://www.computer-forensics-lab.org/pdf/Linux_for_computer_forensic_investigators.pdf Linux for computer forensic investigators: «pitfalls» of mounting file systems]

Revision as of 17:36, 3 February 2010

The problem

Forensic Linux Live CD distributions 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. Community-developed distributions are not exception here, unfortunately. Finally, it turns out that many forensic Linux Live CD distributions are not tested properly and there are no suitable test cases developed.

Another side of the problem

Another side of the problem of insufficient testing of forensic Live CD distributions is that many users do not know what happens "under the hood" of such distributions and cannot adequately test them.

Example

For example, 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).

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.

Problems

Here is a list of common problems of forensic Linux Live CD distributions that can be used by developers and users for testing purposes. Each problem is followed by an up to date list of distributions affected.

Journaling file systems updates

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:

File system When data writes happen 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 "norecovery" flag does not help. To disable data writes: use "ro,loop" flags. The bug was fixed in recent 2.6 kernels.

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 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).

Helix3: damaged Ext3 recovery during the boot

List of distributions that recover Ext3 (and sometimes Ext4) file systems during the boot:

Distribution Version
Helix3 2009R1
SMART Linux (Ubuntu) 2010-01-20
FCCU GNU/Linux Forensic Boot CD 12.1
SPADA 4

Root file system spoofing

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.

grml mounted root file system from the hard drive

Currently, Casper may select fake root file system image on evidentiary media (e.g. 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.

List of Ubuntu-based distributions that allow root file system spoofing:

Distribution Version Notes
Helix3 2009R1
Helix3 Pro 2009R3
CAINE 1.5
DEFT Linux 5
Raptor 20091026
grml 2009.10 Actually, grml uses live-initramfs scripts (Casper fork)
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.

Swap space activation

Incorrect mount policy

HAL

rebuildfstab and scanpartition scripts

Incorrect write-blocking approach

See also