Computer Forensics: First Responder Training - Eric Vanderburg - JurInnov

Computer Forensics
First Responder Training
August 28-30, 2012

Timothy M. Opsitnick, Esq.
Senior Partner and General Counsel
JurInnov Ltd.

Eric A. Vanderburg, MBA, CISSP
Director, Information Systems and Security
Computer Forensic and Investigation Services

John G. Liptak, ACE, EnCE

Senior Consultant
Computer Forensic and Investigation Services

© 2009 Property of JurInnov Ltd. All Rights Reserved

Who Are We?
JurInnov works with organizations that want to
more effectively manage matters involving
“Electronically Stored Information” (ESI).
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Electronic Discovery
Computer Forensics
Document and Case Management
Computer & Network Security

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Presentation Overview
• Understanding Computing Environments
• Collecting Electronically Stored
Information
• Forensic Analysis Demonstration
• Types of Cases When Forensics Are Useful

3

What is Computer Forensics?
Computer Forensics is a scientific, systematic
inspection of the computer system and its contents
utilizing specialized techniques and tools for
recovery, authentication, and analysis of electronic
data. It is customarily used when a case involves issues
relating to reconstruction of computer usage, examination
of residual data, authentication of data by technical
analysis or explanation of technical features of data and
computer usage. Computer Forensics requires specialized
expertise that goes beyond normal data collection and
preservation techniques available to end-users or system
support personnel.
4

Sources of “ESI”
• Desktops

• E-Mail

• Laptops

• Archives

• CDs/DVDs

• Cell Phones/PDAs

• Network Attached
Storage Devices (NAS)

• Thumb Drives

• Storage Area Networks
(SAN)

• Memory Cards

• Servers

• Cameras

• Databases

• Printers

• Backup Tapes

• GPS Devices

• External Storage Devices

2009
5

Why Computer Forensics?
• Reasons to use Computer Forensics
– Internal Company Investigations
• Alleged criminal activity
• Civil or Regulatory Preservation
– Receivership, Bankruptcy
– EEO issues
– Improper use of company assets
– Recovery of Accidentally or Intentionally Deleted Data
• Deleted is not necessarily deleted
• Recovery from Improper shutdowns

6

How Does a Computer Operate?
• Hardware
– Processor
– Memory (RAM)
– Hard Drive
– CD/DVD Drive
– Motherboard
– Mouse/Keyboard
• Software
– Operating System
– Applications
7

How Does a Computer Operate?

• How is data stored on a hard drive?
• How is data “deleted” by the operating system?

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Collecting “ESI”
• Windows Copy

• Ghost Copy/Images
• Forensic Images

11

Collecting “ESI”
• Forensic Harvesting - Logical v Physical
– Logical copy (Active Files)
• Data that is visible via the O.S.
– Physical
• Logical + File Slack + Unallocated Space +
system areas (MBR, Partition table, FAT/MFT)

12

First Response
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First Steps Taken
– Identify users/custodians, electronic devices and
begin Chain of Custody
– Photograph and document full environment and
condition/state of devices
– Determine next steps depending on device(s) and
situation

13

Acquisition (Data Harvest)
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Equipment and Tools
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Write Blockers
Camera
Forensically wiped hard drives
Screw Drivers
Anti-static bags
Power Strips and extension cords
Blank CDs and DVDs / USB Flash Drives
SD Card / Micro Card Reader
Fans for cooling drives during imaging
14


Acquisition (Data Harvest)
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Software Tools
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EnCase (Guidance Software)
Forensic Tool Kit (AccessData)
Mobile Phone Examiner (AccessData)
Device Seizure (Paraben)
Raptor (Forward Discovery)
Internet Evidence Finder (Magnet Forensics)

• Hardware Tools
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Write Blockers (Tableau)
CellDEK (Logicube)
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Types of Data Acquisitions
• Image Types
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EnCase Image (.E01)
Logical EnCase Image (.L01)
DD Image (.001)
Custom Content Image (.AD1)

• ESI Locations
– Hard Drives
– Servers
• Email
• Network Shares

– Cell Phone/PDA
– External Media
16

Computer Imaging
• Photograph, document and begin Chain of Custody
• Acquire live RAM (if possible/necessary)
• Shut down computer
– Pull plug (Windows/Mac)
– Properly shut down (Server/Linux/Unix)

• Determine imaging method and format
– Write Blocker
– Boot Disk
• USB / eSata / FireWire
• Crossover Cable

17

Computer Imaging
• Imaging Process
– Set segment size, type of image, name and compression
– Create forensic image utilizing selected method
– Verify Image Hash Value

• Check BIOS clock and document date/time
– Make note of any differences from actual date/time

• Re-Install hard drive if removed and verify that the
computer boots to the OS
• Create “Work” drive of collected images
– Connect Backup drive to a write blocker to ensure no
changes to the original data occurs

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Device Imaging

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Creating a “Work” drive

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Image Verification
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Presentation Suspect
Description:
Physical Size:
Starting Extent:
Name: Presentation
Actual Date:
Target Date:
File Path:
Case Number:
Evidence Number:
Examiner Name:
Drive Type:
File Integrity:

Images
Physical Disk, 39102336 Sectors, 18.6GB
512
1S0
Suspect Images
03/24/09 03:17:21PM
03/24/09 03:17:21PM
E:Presentation image.E01
Presentation Drive
Presentation Suspect Images
Stephen W. St.Pierre
Fixed
Completely Verified, 0 Errors

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Acquisition Hash:
Verify Hash:

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GUID: 04d345276275524c8a111824be6eb170
EnCase Version:
5.05j
System Version:
Windows 2003 Server
Total Size:
20,020,396,032 bytes (18.6GB)
Total Sectors:
39,102,336

5cfa3830c3af83741da4f9adcfb896e1
5cfa3830c3af83741da4f9adcfb896e1

21

Work Images
• Creating Work copy of original Backup Image
– Evidence Mover Log:
03/25/09 16:20:14 - Source file: F:EvidencePresentation image.E01
Destination file: G:EvidencePresentation image.E01.
Attempt# 1
Hash :9348B9FECFE8023FA3095FB710AFD678
Attempt# 1
Hash :363293E77BB1C974FD82DE7EC3CE1842
Attempt# 1
Hash :3AA6885A045E8F5D20899113A4848917

22

USB Thumb Drive Acquisition
• Photograph, document and begin Chain of Custody
• Determine imaging method and format
– Hardware write blocker
– Software Registry Write Block

• Imaging Process
– Create forensic image utilizing selected method
– Verify image(s) hash value

23

Network Data Collection
• Photograph and document
• Coordinate with IT to determine location of desired
shares/folders
• Obtain proper credentials to access target data
• Attach forensically wiped hard drive to server or
workstation with local network access
• Run FTK Imager Lite from attached hard drive
• Create Custom Content Image (.AD1) of target
shares/folders
• Verify image MD5 hash value

24

Network Data AD1 Image
Add To Custom
Content Image (AD1)

Add Contents of a
Folder
25

Network Data AD1 Image
Create Custom Content
Image

Verify Hash Value of AD1

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Microsoft Exchange Collection
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Photograph and document
Stop Microsoft Exchange services
Attach forensically wiped hard drive to Exchange server
Run FTK Imager Lite from attached hard drive
Create Custom Content Image (.AD1) of Exchange .EDB
files
• Verify image MD5 hash values
• Restart all Microsoft Exchange services

27

Microsoft Exchange Cont.
• Select Mailbox Collection
– Exchange 2003
• ExMerge

– Exchange 2007 & 2010
• Command Line/Power Shell

28

Registry Overview
• Windows Registry – central database of the
configuration data for the OS and applications.
• Gold Mine of forensic evidence
• Registry Keys
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Software
System
SAM (Security Account Manager)
NTUSER.dat

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Software Key
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What Operating System Installed?
Date/Time OS Installed
Product ID For Installed OS
Installed software
Programs That Run Automatically at Startup (Place
to Hide Virus)
• User Profiles

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System Key
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Mounted Devices
Computer Name
USB Plugged-In Devices (USBSTOR)
Last System SHUT DOWN Time
Time Zone

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SAM & NTUSER.DAT Keys
• SAM
– Domain Accounts

• NTUSER.DAT
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Network Assigned Drive Letters
Last Clean Shutdown Date/Time
Recent Documents
Program settings

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Forensic Analysis
• Registry Analysis
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OS Install date/time
Installed Software
Startup programs
Time Zone settings
Last Shutdown time
User information / Accounts
Recently opened files
Connected USB Devices
Mounted Drives
Recently used programs
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Registry – OS Install Date

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Registry – Installed Software

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Registry – Startup Programs

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Registry – Time Zone Settings

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Registry – Last Shutdown Time

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Registry – User Info/Accounts

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Registry – User Info/Accounts

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Registry – Recently Opened

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Registry – USB Devices

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Registry – Mounted Drives

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Registry – Recent Programs

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Forensic Analysis
• USB / External HDD Analysis
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Serial Number
Volume Serial Number
Model
First Connected
Last Connected
Friendly Name
User who connected drive
.LNK Files

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USB/External HDD Analysis

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Forensic Analysis
• Internet History
– Default internet browser
– Sites visited and frequency
– Date and time of last visit

• Recent Folder
– Recently accessed files/programs

• My Documents / User Folder(s)
– Usually where most user created data is located

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Internet History Analysis

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Internet History Analysis

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Forensic Analysis
• Deletion
– Recycle Bin
• Examine INFO2 records if file was sent to the recycle bin
– Contains the date & time the file was sent to the recycle bin
– Shows where the file resided before being sent to the recycle
bin

– Data Carving
– Evidence of wiping or wiping software
• Hex Editor sometimes helps to see wiping pattern if one
exists
– Example recovery of deleted document…..

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“deleted.txt” exists on a disk

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The file has been deleted

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The directory listing…
Note the sigma character

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Is the data really gone???

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Sigma changed to Underscore

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Hey … it’s back!

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VOILA…

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Deleted & Overwritten File

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Recycle Bin Info Record Finder
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These files were recovered by searching for recycle bin header signatures in unallocated and slack space. These
records represent files that were contained in the recycle bin before it was emptied.

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Info records for file:
Demo caseRevised demo imagesCRECYCLERS-1-5-21-1229272821-1592454029-839522115-1003INFO2

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Index
:2
Deleted : 11/06/07 03:30:54PM
FileSize : 20480 bytes (20 KB)
FilePath : C:Documents and SettingsDemoMy DocumentsABC Sports Agency - DeletedRec
ycle Bin - ABC Balance Sheet.xls
Offset : 820

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Index
:2
Deleted : 11/06/07 10:30:54AM
FileSize : 20480 bytes (20 KB)
FilePath : C:Documents and SettingsDemoMy DocumentsABC Sports Agency - DeletedRec
ycle Bin - ABC Balance Sheet.xls
Offset : 1080


Forensic Analysis
• File Signature Analysis
• File Hash Analysis

• Analysis Examples …

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Signature Analysis

2009

Hash Analysis

2009

Forensic Analysis
• Key Term Searching
– Index full contents of the image for searching
– Tips for this method

• File Filtering
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Date ranges
File type(s)
Duplicates
Known Files (KFF)
Even combinations of multiple filters

65

Forensic Analysis
• Email Activity
• Printing Activity
– Look for printing spool/shadow files
• Can possibly contain the data that was sent to a printer

• Network Activity
• Network connections
• Wireless access points
• Shared network folders/files

66

Forensic Analysis
• Hiberfil.sys Analysis
– Data is written to “hiberfil.sys” file when a machine is put
in hibernation mode on the Windows OS
• Usually recent data

– May contain passwords, login information, temporary data,
whole or partial documents

• RAM Analysis
– Can only be acquired on a live system
• Analyst will change data on the system

– May contain passwords, login information, temporary data,
whole or partial documents, currently running processes

67

Forensic Analysis
• Unallocated Space
– Partial documents
– Overwritten files

• Drive Free Space
• File Slack

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Mobile Device Acquisition
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Photograph, document and begin Chain of Custody
Obtain password if enabled
Obtain charger and maintain power to the device
Cut off network communications
– Faraday bag or Airplane Mode

• Determine acquisition/data extraction method
– Device
• CellDek
• Device Seizure
• MPE+

– SIM Card – CellDek, Device Seizure or MPE+
– Media/SD Card - EnCase
69

Mobile Device Analysis
• Not to be considered an “Image”
– Extraction of artifacts from device’s databases

• Some Items That Can Be Acquired
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SMS/MMS
Email
Contacts
Calendar

• Searching
– Able to search within the device’s extracted data for key
terms.
– Bookmark items that are relevant to the case
70

Mobile Device Analysis
• Reporting
– Tools include report generators
• HTML
• CSV / XLS
• PDF

– Include ALL items or only Bookmarked items
• Helps to limit amount of irrelevant data in the reports

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Evidence/Analysis Reporting
• Native File Exports
– Provide files in native format on CD, DVD or External HDD
– Allows client to view the files as the custodian did
– Keeps metadata intact

• Metadata Report
– Excel spreadsheet containing all the metadata of the
native file export
– Easy way to look through and sort the files in one place

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Evidence/Analysis Reporting
• Detailed Forensic Report
– Report done throughout and after every case
– Details all work done by forensic analysts from beginning
to end

• HTML Based Reports
– FTK, Device Seizure, CellDEK, Internet Evidence Finder
– Simple report in web format for easy viewing

• Final Expert Report
– Completed & signed version of the detailed forensic report

• Expert Testimony
– Analysts will provide expert testimony in court if required.
73

For assistance or additional information
• Phone:
• Web:
• Email:

216-664-1100
www.jurinnov.com
tim.opsitnick@jurinnov.com
eric.vanderburg@jurinnov.com
john.liptak@jurinnov.com
JurInnov Ltd.
The Idea Center
1375 Euclid Avenue, Suite 400
Cleveland, Ohio 44115
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