cos 413 day 2. agenda questions? assignment 1 due next class finish discussion on preparing for...

COS 413

DAY 2

Agenda

• Questions?• Assignment 1 due next class• Finish Discussion on Preparing for Computing

Investigations• Begin Discussion on Understanding Computer

Investigations• Tomorrow Lab will be in OMS Room 120

– Pick a lab partner (PSA/COS teams)– You will need 4 1.44 floppies– Hands-on Projects (page 66) Projects 2-1 and 2-2– Lab write-up due in before next lab (One grade per team)

Public Service Announcement• From Steve Worona [[email protected]]

– From 1-2pm Eastern Time this Thursday, September 15, I'll have the pleasure of hosting David Post on EDUCAUSE Live! David has been an ICPL participant since we began the program in 1996, speaking on the general topic of Internet governance. On Thursday, his topic will be "Whose Law? The Problem of 'Jurisdiction' on the Internet". Here's the abstract:

• The question "What law am I obligated to obey?" is a fundamental one in any legal system and one that every lawyer should be able to answer for his or her client. It is, though, deceptively complex-even in the non-Internet context. David Post will try to make some sense of this question as applied to activity on the Internet, both by presenting a very general framework for thinking about "jurisdictional" questions and by analyzing a number of recent cases raising specific jurisdictional issues.

– There's no charge for the Webcast, but registration is required at <http://www.educause.edu/live0518>.

– EDUCAUSE Live! is open to all; feel free to pass the word. All EDUCAUSE Live! events are archived for future access.

Preparing For Computer Investigations Preparing For Computer Investigations (continued)(continued)

Understanding Enforcement Agency Understanding Enforcement Agency InvestigationsInvestigations

• Understand:– Local city, county, state or province, and federal laws

on computer-related crimes– Legal processes and how to build a criminal case

Understanding Enforcement Agency Understanding Enforcement Agency Investigations (continued)Investigations (continued)

• States have added specific language to their criminal codes to define crimes that involve computers

• Until 1993, laws defining computer crimes did not exist

Following the Legal ProcessFollowing the Legal Process

• A criminal case follows three stages: – Complaint

• Someone files a complaint

– Investigation• A specialist investigates the complaint

– Prosecution • Prosecutor collects evidence and builds a case

Following the Legal Process Following the Legal Process (continued)(continued)


• Levels of law enforcement expertise:– Level 1 (street police officer)

• Acquiring and seizing digital evidence– Level 2 (detective)

• Managing high-tech investigations• Teaching the investigator what to ask for• Understanding computer terminology• What can and cannot be retrieved from digital

evidence– Level 3: (computer forensics expert)

• Specialist training in retrieving digital evidence

Understanding Corporate Understanding Corporate InvestigationsInvestigations

• Business must continue with minimal interruption from your investigation

• Corporate computer crimes: – E-mail harassment– Falsification of data– Gender and age discrimination– Embezzlement– Sabotage– Industrial espionage

Establishing Company PoliciesEstablishing Company Policies

• Company policies avoid litigation

• Policies provide:– Rules for using company computers and networks– Line of authority for internal investigations

• Who has the legal right to initiate an investigation

• Who can take possession of evidence

• Who can have access to evidence

Displaying Warning BannersDisplaying Warning Banners

• Avoid litigation displaying a warning banner on computer screens

• A banner:– Informs user that the organization can inspect

computer systems and network traffic at will – Voids right of privacy– Establishes authority to conduct an investigation

Displaying Warning Banners Displaying Warning Banners (continued)(continued)


• Types of warning banners: – For internal employee access (intranet Web page

access) – External visitor accesses (Internet Web page

access)


• Examples of warning banners:– Access to this system and network is restricted– Use of this system and network is for official

business only– Systems and networks are subject to monitoring at

any time by the owner– Using this system implies consent to monitoring by

the owner– Unauthorized or illegal users of this system or

network will be subject to discipline or prosecution


• A for-profit organization banner – This system is the property of Company X– This system is for authorized use only– Unauthorized access is a violation of law and

violators will be prosecuted– All activity, software, network traffic, and

communications are subject to monitoring

Designating an Authorized RequesterDesignating an Authorized Requester

• Establish a line of authority • Specify an authorized requester who has the power

to conduct investigations• Groups who can request investigations:

– Corporate Security Investigations– Corporate Ethics Office– Corporate Equal Employment Opportunity Office– Internal Auditing– The general counsel or legal department

Conducting Security InvestigationsConducting Security Investigations

• Public investigations search for evidence to support criminal allegations

• Private investigations search for evidence to support allegations of abuse of a company’s assets and criminal complaints

Conducting Security Investigations Conducting Security Investigations (continued)(continued)

• Situations in the enterprise environment:– Abuse or misuse of corporate assets– E-mail abuse– Internet abuse


• Employee abuse of computer privileges– Employee company startup– Porn site– Malicious e-mail

Distinguishing Personal and Company Distinguishing Personal and Company PropertyProperty

• PDAs and personal notebook computers

• Employee hooks up his PDA device to his company computer

• Company gives PDA to employee as bonus

Maintaining Professional Conduct Maintaining Professional Conduct

• Professional conduct determines credibility– Ethics– Morals– Standards of behavior– Maintain objectivity and confidentiality– Enrich technical knowledge– Conduct with integrity

Maintaining Professional Conduct Maintaining Professional Conduct (continued)(continued)

• Maintaining objectivity– Sustain unbiased opinions of your cases

• Avoid making conclusions about the findings until all reasonable leads have been exhausted

• Considered all the available facts

• Ignore external biases to maintain the integrity of the fact-finding in all investigations

• Keep the case confidential


• Stay current with the latest technical changes in computer hardware and software, networking, and forensic tools

• Learn about the latest investigation techniques that can be applied to the case

• Record fact-finding methods in a journal– Include dates and important details that serve as

memory triggers– Develop a routine of regularly reviewing the journal

to keep past achievements fresh


• Attend workshops, conferences, and vendor-specific courses conducted by software manufacturers

• Monitor the latest book releases and read as much as possible about computer investigations and forensics

SummarySummary

• Computer forensics: systematic accumulation of digital evidence in an investigation

• Differs from network forensics, data recovery, and disaster recovery in scope, technique, and objective

• Laws relating to digital evidence were established in the late 1960s

• To be successful, you must be familiar with more than one computing platform

Summary (continued)Summary (continued)

• To supplement your knowledge, develop and maintain contact with computer, network, and investigative professionals

• Public investigations typically require a search warrant before the digital evidence is seized

• The Fourth Amendment applies to governmental searches and seizures

• During public investigations, you search for evidence to support criminal allegations


• During private investigations, search for evidence to support allegations of abuse of a company or person’s assets and, in some cases, criminal complaints

• Silver-platter doctrine: handing the results of private investigations over to the authorities because of indications of criminal activity

• Forensics investigators must maintain an impeccable reputation to protect credibility


• Most information is stored on hard disks, floppy disks, and CD-ROMs in a nonvolatile manner

• Peripheral components (video adapter cards, sound cards, mice, keyboards, NICs) attach to mainboard via an expansion slot or port

• All peripherals must have a unique IRQ and I/O address to communicate with the processor

• Hardware information can be gathered from computer manuals, BIOS, or other OSs

Guide to Computer Guide to Computer Forensics and Forensics and Investigations Investigations

Chapter 2Understanding Computer Investigation

ObjectivesObjectives

• Prepare a case

• Begin an investigation

• Understand computer forensics workstations and software

Objectives (continued)Objectives (continued)

• Conduct an investigation

• Complete a case

• Critique a case

Preparing a Computer Investigation Preparing a Computer Investigation

• Role of computer forensics professional: gather evidence to prove a suspect committed a crime or violated a company policy

• Collect evidence that can be offered in court or at a corporate inquiry– Investigate the suspect’s computer– Preserve the evidence on a different computer

Preparing a Computer InvestigationPreparing a Computer Investigation(continued)(continued)

• Follow an accepted procedure to prepare a case

• Chain of custody– Route the evidence takes from the time you find it

until the case is closed or goes to court

Examining a Computer CrimeExamining a Computer Crime

• Computers can contain information that helps law enforcement determine:– Chain of events leading to a crime– Evidence that can lead to a conviction

• Law enforcement officers should follow proper procedure when acquiring the evidence– Digital evidence can be easily altered by an

overeager investigator

Examining a Computer Crime Examining a Computer Crime (continued)(continued)

Examining a Company Policy ViolationExamining a Company Policy Violation

• Employees misusing resources can cost companies millions of dollars

• Misuse includes:– Surfing the Internet– Sending personal e-mails– Using company computers for personal tasks

Taking a Systematic ApproachTaking a Systematic Approach

• Steps for problem solving: – Make an initial assessment about the type of case

you are investigating– Determine a preliminary design or approach to the

case– Create a detailed design– Determine the resources you need– Obtain and copy an evidence disk drive

Taking a Systematic ApproachTaking a Systematic Approach(continued)(continued)

• Steps for problem solving (continued): – Identify the risks– Mitigate or minimize the risks– Test the design– Analyze and recover the digital evidence– Investigate the data you recovered– Complete the case report– Critique the case

Assessing the CaseAssessing the Case

• Systematically outline the case details:– Situation– Nature of the case– Specifics about the case– Type of evidence– OS– Known disk format– Location of evidence

Assessing the Case (continued)Assessing the Case (continued)

• Based on case details, you can determine the case requirements: – Type of evidence– Computer forensics tools– Special OSs

Planning your InvestigationPlanning your Investigation

• A basic investigation plan should include the following activities: – Acquire the evidence– Complete an evidence form and establish a chain of

custody– Transport evidence to a computer forensics lab– Secure evidence in an approved secure container

Planning your InvestigationPlanning your Investigation(continued)(continued)

• A basic investigation plan (continued):– Prepare a forensics workstation– Obtain the evidence from the secure container– Make a forensic copy of the evidence– Return the evidence to the secure container– Process the copied evidence with computer

forensics tools


• An evidence custody form helps you document what has been done with the original evidence and its forensics copies

• There are two types:– Single-evidence form– Multi-evidence form

Securing your EvidenceSecuring your Evidence

• Use evidence bags to secure and catalog the evidence

• Use computer safe products– Antistatic bags– Antistatic pads

• Use well-padded containers

Securing your Evidence (continued)Securing your Evidence (continued)

• Use evidence tape to seal all openings– Floppy disk or CD drives– Power supply electrical cord

• Write your initials on tape to prove that evidence has not been tampered

• Consider computer-specific temperature and humidity ranges

Understanding Data-Recovery Understanding Data-Recovery Workstations and SoftwareWorkstations and Software

• Investigations are conducted on a computer forensics lab (or data-recovery lab)

• Computer forensics and data-recovery are related but different

• Computer forensics workstation– Specially configured personal computer

• To avoid altering the evidence, use:– Forensics boot floppy disk– Write-blockers devices

Setting Up your Workstation for Setting Up your Workstation for Computer ForensicsComputer Forensics

• Set up Windows 98 workstation to boot into MS-DOS – Display a Startup menu– Modify Msdos.sys file using any text editor

• Install a computer forensics tool – DriveSpy and Image

• From start menu -> msconfig (ok) -> select advanced

Setting Up your Workstation for Setting Up your Workstation for Computer Forensics (continued)Computer Forensics (continued)

Setting Up your Workstation for Setting Up your Workstation for Computer Forensics (continued)Computer Forensics (continued)

Modify MSDOS.SYS file

Conducting an InvestigationConducting an Investigation

• Begin by copying the evidence using a variety of methods– Recall that no single method retrieves all data– The more methods you use, the better

Gathering the EvidenceGathering the Evidence

• Take all necessary measures to avoid damaging the evidence– Place the evidence in a secure container

• Complete the evidence custody form

• Transport the evidence to the computer forensics lab

• Create forensics copies (if possible)

• Secure evidence by locking the container

Understanding Bit-stream CopiesUnderstanding Bit-stream Copies

• Bit-by-bit copy of the original storage medium

• Exact copy of the original disk

• Different from a simple backup copy– Backup software only copy known files– Backup software cannot copy deleted files or e-mail

messages, or recover file fragments

Understanding Bit-stream Copies Understanding Bit-stream Copies (continued)(continued)

• A bit-stream image file contains the bit-stream copy of all data on a disk or partition

• Preferable to copy the image file to a target disk that matches the original disk’s manufacturer, size, and model

Understanding Bit-stream CopiesUnderstanding Bit-stream Copies(continued)(continued)

Copying the Evidence DiskCopying the Evidence Disk

• A forensic copy is an exact duplicate of the original data

• Create a forensic copy using:– MS-DOS– Specialized tool such as Digital Intelligence’s Image

• First, create a bit-stream image

• Then, copy the image to a target disk

Copy Using MSDOSCopy Using MSDOS

• Write protect original (move tab)

• Boot to MSDOS mode

• Insert original floppy in drive

• Type “Diskcopy A: A: /v”

• Insert new floppy when prompted

• Label new floppy

• Resecure oprignal floppy to secure evidence locker

Coping using Coping using ImageImage


• Insert original floppy

• Change to work folder

• Acquire image from disk– Image a: c:\work\..\daImage.img

• Remove original floppy

Restoring an imageRestoring an image


• Insert new floppy

• Change to work folder

• restore image from disk– Image daImage.img a:

• Remove new floppy and label

Analyzing the digital evidenceAnalyzing the digital evidence

• Using DriveSpy– Page 55-61 in text

Completing the CaseCompleting the Case

• You need to produce a final report– State what you did and what you found

• You can even include logs from the forensic tools you used

• If required, use a report template

• The report should show conclusive evidence that the suspect did or did not commit a crime or violate a company policy

Critiquing the CaseCritiquing the Case

• Ask yourself the following questions:– How could you improve your participation in the

case?– Did you expect the results you found?– Did the case develop in ways you did not expect?– Was the documentation as thorough as it could have

been?

Critiquing the Case (continued)Critiquing the Case (continued)

• Questions continued:– What feedback has been received from the

requesting source?– Did you discover any new problems? What are they?– Did you use new techniques during the case or

during research?

SummarySummary

• Use a systematic approach to investigations

• Plan a case by taking into account:– Nature of the case– Case requirements– Gathering evidence techniques

• Do not forget that every case can go to court

• Apply standard problem-solving techniques


• Keep track of the chain of custody of your evidence

• Create bit-stream copies of the original data

• Use the duplicates whenever possible

• Some tools: DriveSpy and Image, FTK, MS-DOS commands

• Produce a final report detailing what you did and found


• Always critique your work as a way of improving it

• Apply these lessons to future cases

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