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International Journal of Advanced Research in Computer Engineering & Technology
Volume 1, Issue 5, July 2012

COMPREHENSIVE STUDY OF DIGITAL FORENSICS

Jatinder kaur, Gurpal Singh

SMCA, Thapar University, Patiala-147004, India

jyoti929@gmail.com, gurpalsingh123@gmail.com



Abstract— This paper presenting the review about digital
forensics, it consists of techniques as well as various tools used
to accomplish the tasks in the digital forensic process. Network
forensics is forensics and important technology for network
security area. In this paper, we inspect digital evidence
collection processes using these tools. From last few decades the
Figure 1 : Shows processes to collect digital data
digital forensic techniques have been improved appreciably but
still we face a lack of effective forensics tools to deal with varied
incidents caused by these rising technologies and the advances 2. Collect, observe & preserve.
in cyber crime. This article discusses the tools used in network 3. Analyze , identify and
forensics , various gaps founds in these tools, and the 4. Rebuild the evidence and verify the result every time [16].
advantages and disadvantages of these tools.
In the document describe digital evidence collection process
Index Terms— Forensics, Digital evidence, Network forensics, as follows:
computer forensics, Cyber crime , Encase, Sleuth Kit.
1. Where is the evidence? List out the systems were involved
in the incident and from which evidence will be collected.
I. INTRODUCTION
2. Establish what is likely to be relevant and admissible.
Forensics is use of science and technology to investigate and
When in doubt err on the side of collecting too much rather
establish facts in criminal and civil courts of law. Internet
than not enough.
Forensics includes techniques and methodologies to collect ,
preserve and analyze digital data on the internet for
3.For each system, obtain the relevant order of volatility.
investigation purposes.
It is a field of research and practice that has evolved as a
4. Remove external avenues for change.
result of increasing internet usage and the move of criminal
activity. It is also argued that internet forensics evolved as a
5. Following the order of volatility, collect the evidence with
response to the hacker community.
tools
Digital forensics focuses on developing evidence pertaining
to digital files that relate to a computer document, email, text,
6.Record the extent of the system's clock flow.
digital photograph, software program, or other digital record
7. Question what else may be evidence as you work through
which may be at issue in a legal case. It is a branch of forensic
the collection steps.
science to monitor, analyze and examine digital media or
8.Document each step.
devices. The government and the corporate security firms
dedicate significant resources to investigating the insider
9. Don't forget the people involved. Make notes of who was
computer attacks that continue to plague organization a
there and what were
worldwide. Computer forensics process consist of
they doing, what they observed and how they reacted[2].
Preparation, Acquisition , Preservation, Examination and
analysis and Reporting[1] . Among these steps, Acquisition
step is a procedure that investigators collect digital evidence
and garauntee integrity of evidence at incident site. II. WHY WE NEED FOR DIGITAL FORENSICS?
Accordingly , Acquisition step most significant step for
efficient investigation. Unauthorised access : This occurs when a user/hacker
Cyber Analyst performs the following tasks while working deliberately gets access into someone else’s network either
with digital evidences: to monitor or data destruction purposes[3].
1. Identify: Any digital information or artifacts that can be
used as evidence Denial of service attack : It involves sending of
disproportionate demands or data to the victims server

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beyond the limit that the server is capable to handle and 2. Access Data’s FTK
hence causes the server to crash. Drive Spy is a powerful tool that recovers and analyses data
on FAT 12, FAT 16, and FAT 32disks can search for altered
Virus ,Worms and Trojan attacks : viruses are basically files and keywords[4].
programs that are attached to a file which then gets circulated
to other files and gradually to other computers in the FTK is an easy to use GUI application for FAT 12, FAT 16,
network. and FAT 32 and new technology file system (NTFS) disks

Worms unlike viruses do not need a host for attachments 1. FTK Imager
they make copies themselves and do this repeatedly hence 2. Registry Viewer
eating up all the memory of the computer. 3. Password Recovery Toolkit

III. ENABLED STRATEGIES TO COMPUTER IV. VARIOUS TECHNOLOGIES USED FOR FORENSICS : TOOLS
FORENSICS

Computer forensics involves the preservation, identification, A ENCASE :
extraction, documentation and interpretation of computer
data, in which computer forensics is defined as “an art of This tool is Used to Analyse digital Media. It performs the
science using sophisticated methods and procedures to following function Data acquisition , file recovery, file
preserve, identify, extract, document, examine, analyze and parsing, and hard disk format recovery.
interpret digital evidence.” This methodology and basic It is a network enabled incident response system which offers
principles are briefly stated as follows: immediate and complete forensic analysis of volatile and
static data on compromised servers and workstations
(1) Acquire the evidence without altering or damaging the anywhere on the network, without disrupting operations. It is
original. used for the verification of the data after verifying it gives
the hash value[6]. There are three
(2) Authenticate the recovered evidence as being the same as components of Encase tool which are discussed below:
the originally seized data.
1. The first of these components is the Examiner software
(3) Analyze the data without modifying it. This software is installed on a secure system where
Investigations and audits are performed.
The computer forensics operating strategies below provide
effective investigation procedures for cyber crime cases. 2. The second component is called SAFE, which stands for
Secure Authentication of EnCase. SAFE is a server
1.Preserve the evidence : Digital evidence can be changed
at any time by striking the keyboard or clicking the mouse. If which is used to authenticate users, administer access
the evidence is not handled properly, it could result in rights, maintain logs of EnCase transactions, and
evidence damage, inaccessible data, inability to prove that provide for secure data transmission.
the suspect committed the crime, or even a possibility of
having no evidence. Therefore, the first step upon arrival at 3. The final component is Servlet, an efficient
the scene of the cyber-crime is to properly control the scene
and begin to record the time, carry out the investigation and component installed on network workstations and
collect all significant digital evidence. servers to establish connectivity between the Examiner,
Digital evidence is, by its very nature, fragile[5]. SAFE, and the networked workstations, servers, or
services being investigated.
2. Examine the evidence: After obtaining the evidence from
the scene, the next step is to analyze it. Common computer
documents, pictures and sounds can be examined by many ENCASE WORKING SNAPSHOTS:
different software programs. However, the biggest problem
is deleted documents, sometimes having been deleted by the How to recover the hard disk format data with the help of
suspect, which could be the most important evidence of all.
Encase tool. In these snapshots the working of the tool is
Thus, slack space in the hard drive must also be scanned; this
is one of the main reasons for using the bit-stream-copy discussed below :
method. A software tool must be used here to do string
searching and document rebuilding.

(3) Evidence analysis: After examination and analysis of the
evidence is to recover data from deleted files, files fragments,
complete files. Tools used for this process are:
1. Digital intelligence’s Drive spy

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B. FTK Explorer

 Developer : Access Data
 Operating System : Windows
 Type : Computer Forensics

Main purpose of this toolkit is to Locate deleted e-mails.
Disk imaging program called FTK Imager.
FTK Imager saves an image of a hard disk in one file that
may be later on reconstructed. Through this toolkit the
Figure:2 Interface of Encase tool recovery of password can be constructed. With the help of
this tool from Winzip, WinRar, Gzip and compressed file
This is the main screen of the encase tool. In this we data is automatically extracted.
will first select the option new and then after
FTK processes data faster than any other computer forensics
selecting the case option and save this new case by
solution. It delivers true distributed processing, allowing you
giving the name as your choice. to divide your processing across four workers. Furthermore,
FTK is the only computer forensics solution to fully leverage
multithreaded, multi-core computers. So while common
forensics tools waste the potential of modern hardware
solutions, FTK will fully utilize anything you throw at it[5].

• Faster more efficient processing
• Cancel/Pause/Resume functionality
• Better real-time processing status
• CPU resource throttling
• Email notification upon processing completion.

FTK delivers advanced memory and volatile analysis to aid
forensic investigators and incident responders.

Memory Analysis:
Enumeration of all running Processes( Including those
Figure:3 Interface working of tool hidden)

1. DLL list
2. Network Sockets
3. Drivers loaded in memory
4. Device driver layering identification
5. Handles
6. Enumeration and hook detection of
7. SCT,IDT and IRP
8. Devices
9. Registry enumeration
10. VAD tree
Memory string search allows you to identify hits in memory
and automatically map them back to a given process, DLL
or piece of unallocated and dump the corresponding item[6].
Figure:4 In this figure there is case folder presented
by this screenshot .

Choose the drive from which you want to recover
the data. After that click next and it will recover the
deleted drive and the content of that hard drive
successfully by this tool. These are the steps of
Encase tool which we can use to recover hard disk
deleted data.

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TSK is a collection command line tools that
provides media management and forensics analysis
functionality. The autopsy forensic browser is a
GUI front end for the TSK product.

SLEUTH KIT CORE TOOLS

1. File System Layer
2. File Name Layer
3. Meta Data Layer
4. Data Unit Layer
5. Media Management
6. hfind
7. mactime
8. sorter

AUTOPSY BROWSER ADDS TO TSK

1. Dead Analysis
2. Live Analysis
Figure:7 FTK interface 3. Case Management
4. Even Sequencer
FTK runs in windows operating system and provides a very 5. Notes
powerful tool set to acquire and examine electronic media. 6. Image Integrity
7. Reports
C. SLEUTH KIT 8. Logging

Sleuth kit runs on windows and Unix system. It is the file
system tool allow you to examine file systems of a suspect V. CONCLUSION
computer in a non-intrusive fashion. Because thetools do not
rely on the operating system to process the file systems, Sleuth Kit along with Autopsy Browser has been selected as
deleted and hidden content is shown. the best tool to implement for hands on training. The purpose
The Sleuth Kit is written in C and Perl . With these tools, you of this paper is to introduce the aforementioned concepts in
the cyber-crime investigations domain and the suitability of
can identify where partitions are located and extract them so
the underlying tools is studied Furthermore, a variety of
that they can be analyzed with file system analysis tools. digital forensics tools include digital evidence bag,
The Sleuth Kit has been tested on[6]: automated logging – network tools in particular – which
• Linux could be interfaced with the proposed system. By doing this,
• Mac OS X a more specialised system equipped with the appropriate
• Windows (Visual Studio ) semantics would allow further exploration of the efficiency
and effectiveness of the tool.By comparing the features of
these given tools in this paper in future we will give a new
design and implementation framework of network forensics
system for these tools with efficient results to collect the
digital evidence.

VI. REFERENCES

[1] Kenneally, E.K., “The Internet is the Computer: the role
of forensics in bridging the digital and physical divide”,
Digital Investigation, Vol. 2, Issue 1, 2005, pp. 41-44.

[2] Chung-Huang Yang,Pei-Hua Yen ” Fast Deployment of
Computer Forensics with USBs” 2010 International
Conference on Broadband, Wireless Computing,
Communication and Applications
Figure:8 Interface of Sleuth kit/Autopsy browser

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[3] Hanan Hibshi Carnegie ,Timothy Vidas Carnegie ,Lorrie
Cranor Carnegie Mellon University Pittsburgh, PA, USA
“Usability of forensics tools: user study” 2011 Sixth
International Conference on IT Security Incident
Management and IT Forensics.

[4] Syed Naqvi, Gautier Dallons, Christophe “Applying
Digital Forensics in the Future Internet Enterprise Systems –
European SMEs’ Perspective”(CETIC) Charleroi, Belgium
2010 Fifth International Workshop on Systematic
Approaches to Digital Forensic Engineering.
[5] Mario Hildebrandt, Stefan Kiltz and Jana Dittmann” A
Common Scheme for Evaluation of Forensic Software”
2011 Sixth International Conference on IT Security Incident
Management and IT Forensics.

[6] Guidance Software, EnCase.
http://www.guidancesoftware.com

[7] Ashley Brinson*, Abigail Robinson, Marcus Rogers “A
cyber forensics ontology: Creating a new approach to
studying cyber forensics” d igital investigation 3 S ( 2 0 0 6 )
S 3 7 – S 4 3.

[8] Frank Y.W. Law, K.P. Chow, Michael Y.K. Kwan, Pierre
K.Y. Lai “Consistency Issue on Live Systems Forensics”.

[9] Yong-Dal Shin* ”New Digital Forensics Investigation
Procedure Model” Fourth International Conference on
Computing and Advanced Information Management.

[10] Seokhee Lee, Hyunsang Kim, Sangjin Lee, “Digital
evidence collection process in integrity and memory
information gathering”.

[11] Dan Manson, Anna Carlin, Steve Ramos, Alain Gyger,
Matthew Kaufman, Jeremy Treichelt “Is the Open Way a
Better Way?Digital Forensics using Open Source Tools”
Proceedings of the 40th Hawaii International Conference on
System Sciences – 2007”.

[12] Marcus K. Rogers, Kate Seigfried” The future of
computer forensics: a needs analysis survey” Received 21
November 2003; accepted 6 January 2004.

[13] Maria Karyda and Lilian Mitrou,” Internet Forensics:
Legal and Technical Issues” Second International Workshop
on Digital Forensics and Incident Analysis (WDFIA 2007).

[6] Simson L. Garfinkel,” Automating Disk Forensic
Processing with SleuthKit, XML and Python” 2009 Fourth
IEEE International Workshop on Systematic Approaches to
Digital Forensic Engineering.

.

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