ALBERT J. MARCELLA, Ph.D. & ROBERT S. GREENFIELD Editors
A Field Manual for Collecting, Examining, & Preserving Evidence of Computer Crimes
Editors and Contributors
Albert J. Marcella, Jr., Ph.D., CFSA, COAP, CQA, CSP, CDP, CISA, is an associate professor of Management in the School of Business and Technology, Department of Management, at Webster University, in Saint Louis, Missouri. Dr. Marcella remains the president of Business Automation Consultants, an information technology and management−consulting firm he founded in 1984. Dr.Marcella has completed diverse technical security consulting engagements involving disaster recovery planning, site and systems security, IT, financial and operational audits for an international clientele. He has contributed numerous articles to audit−related publications and has authored and co−authored 18 audit−related texts.
Robert S. Greenfield, MCP, has over 16 years of experience as a programmer/analyst, with the
past five years as a systems consultant and software engineer in the consulting field. He has
extensive experience designing software in the client/server environment. In addition to mainframe experience on several platforms, his background includes systems analysis, design, and development in client/server GUI and traditional environments. His client/server expertise includes Visual Basic, Access, SQL Server, Sybase, and Oracle 7.3 development. Mr. Greenfield has created intranet Web sites with FrontPage and distributing applications via the Internet. He currently holds professional accreditation as a Microsoft Certified Professional and continues self paced training to achieve MCSE, MCSD, and MCSE/D + Internet ratings.
Abigail Abraham is an Assistant State's Attorney, prosecuting high−technology crimes for the Cook County State's Attorney's Office in Chicago, Illinois. She was awarded her J.D. from The University of Chicago Law School and served as an editor on the law review. Following law school, she clerked for one year for the Honorable Danny J. Boggs, U.S. Court of Appeals for the Sixth Circuit. She is an adjunct law professor at The University of Chicago Law School. In addition, she has designed training for lawyers and for police officers, and lectures around the country on high−technology legal issues.
Brent Deterdeing graduated from the University of Missouri with a degree in computer science and a minor in economics. Brent's involvement with SANS is extensive. He is an author of an upcoming book on firewalls through SANS, as well as chairing the SANS/GIAC Firewalls Advisory Board. He has mentored both small and large classes through SANS/GIAC Security Essentials Training & Certification (GSEC). Brent also authors, revises, and edits SANS courseware, quizzes, and tests. He has earned the SANS/GIAC GSEC (Security Essentials), GCFW (Firewall Analyst — HONORS), GCIA (Intrusion Analyst), and GCIH (Incident Handling) certifications, as well as being a Red Hat Certified Engineer (RHCE). Brent participates in the St. Louis InfraGard chapter.
John W. Rado is a geospatial analyst at National Imagery and Mapping Agency (NIMA) in St.
Louis, Missouri. John has worked for NIMA since January of 1991.
William J. Sampias has been involved in the auditing profession for the past decade, with primary emphasis on audits of information systems. Mr. Sampias has published several works in the areas of disaster contingency planning, end−user computing, fraud, effective communications, and security awareness. Mr. Sampias is currently director of a state agency information systems audit group.
Steven Schlarman, CISSP, is a security consultant with PricewaterhouseCoopers. Since joining
the firm in 1998, Steve has covered a number of roles, mainly as the lead developer of the
Enterprise Security Architecture System and Services. He has published articles on the subject as
well as being one of the major thought leaders in the PricewaterhouseCoopers' Enterprise Security Architecture Service line. Prior to joining the firm, Steve had worked on multiple platforms including PC applications, networking, and midrange and mainframe systems. His background includes system security, system maintenance, and application development. Steve has completed numerous technical security consulting engagements involving security architectures, penetration studies ("hacking studies"), network and operating system diagnostic reviews, and computer crime investigation. He has participated in both PC computer forensic analysis and network intrusion management and investigation. Prior to PricewaterhouseCoopers, Steve worked at a U.S. state law enforcement agency in the information systems division.
Carol Stucki is working as a technical producer for PurchasePro.com, a rapidly growing dot.com
company that is an application service provider specializing in Internet−based procurement. Carol's past experiences include working with GTE, Perot Systems, and Arthur Andersen as a programmer, system analyst, project manager, and auditor.
As always with texts of this nature, here is the disclaimer….
The information contained within this field manual is intended to be used as a reference, and not as an endorsement of the included providers, vendors, and informational resources. Reference herein to any specific commercial product, process, or service by trade name, trademark, service mark, manufacturer, or otherwise does not constitute or imply endorsement, recommendation, or favoring by the authors or the publisher.
As such, users of this information are advised and encouraged to confirm specific claims for product performance as necessary and appropriate.
The legal/financial materials and information that are available for reference through this manual are not intended as a substitute for legal/financial advice and representation obtained through legal/financial counsel. It is advisable to seek the advice and representation of legal/financial counsel as may be appropriate for any matters to which the legal/financial materials and information may pertain.
Web sites included in this manual are intended to provide current and accurate information; neither the authors, publisher, nor any of its employees, agencies, and officers can warranty the information contained on the sites and shall not be held liable for any losses caused on the reliance of information provided. Relying on information contained on these sites is done at one's own risk. Use of such information is voluntary, and reliance on it should only be undertaken after an independent review of its accuracy, completeness, efficacy, and timeliness. Throughout this manual, reference links to other Internet addresses have been included. Such external Internet addresses contain information created, published, maintained, or otherwise posted by institutions or organizations independent of the authors and the publisher. The authors and the publisher do not endorse, approve, certify, or control these external Internet addresses and do not guarantee the accuracy, completeness, efficacy, timeliness, or correct sequencing of information located at such addresses. Use of such information is voluntary, and reliance on it should only be undertaken after an independent review of its accuracy, completeness, efficacy, and timeliness.
Introduction
As an auditor as well as researcher and author, I realize and value the importance of timely,
well−focused, accurate information. It is with this philosophy in mind that the development of this project was undertaken.
To the reader, a note of explanation…. This is not a text, but rather a field manual. It has been
written — better yet, compiled — and edited in a manner that will allow you to rapidly access a
specific area of interest or concern and not be forced to sequentially wade through an entire text,
chapter by chapter, to get to what is important to you.
In the true sense of a field manual, each "chapter" (and we use that term loosely) stands on its own and presents focused, timely information on a specific topic related to cyber forensics. The author of each "chapter" was selected for his or her expertise in a specific area within the very broad field of cyber forensics.
Often a limiting aspect of most projects, especially those written on emerging technical topics, is the inability to cover every aspect of the topic in a single all−inclusive text. This truth befalls this field manual that you are about to use.
Initial research into this growing discipline proved that it would be next to impossible to include all the areas of both interest and importance in the field of cyber forensics that would be needed and required by all potential readers and users in a single text. Thus, this field manual presents specific and selected topics in the discipline of cyber forensics, and addresses critical issues facing the reader who is engaged in or who soon will be (and you will!) engaged in the preservation, identification, extraction, and documentation of computer evidence.
As a user of this field manual, you will see that this manual's strength lies with the inclusion of an
exhaustive set of chapters covering a broad variety of forensic subjects. Each chapter was
thoroughly investigated; examined for accuracy, completeness, and appropriateness to the study of cyber forensics; reviewed by peers; and then compiled in a comprehensive, concise format to
present critical topics of interest to professionals working in the growing field of cyber forensics.
We finally had to select several key areas and put pen to paper, entice several colleagues to share
their ideas, and resign ourselves to the fact that we cannot say all that needs to be said in one text,
book, or manual. We trust the material we have included will serve as a starting point for the many professionals who are beginning their journey into this exciting discipline.
We begin our journey into the realm of this relatively new discipline by opening with a brief
discussion as to the current state of the environment relating to the need for this new field of
forensics and then a brief examination of the origins of cyber forensics. Along the way, we will
establish several basic definitions designed to assist the reader in moving easily through what could be difficult and confusing terrain.
Although e−mail is becoming more mission−critical for enterprises, it also has the
ability to haunt a company in times of trouble, because records of e−mail messages
remain in the company systems after deletion — a feature highlighted during the
Microsoft anti−trust trial. The case has featured critical testimony derived from old
Microsoft e−mail messages.
—InfoWorld, 10/25/99
Computer Forensics
Computer Forensics deals with the preservation, identification, extraction, and documentation of
computer evidence. The field is relatively new to the private sector but it has been the mainstay of
technology−related investigations and intelligence gathering in law enforcement and military
agencies since the mid−1980s.
Like any other forensic science, computer forensics involves the use of sophisticated technology
tools and procedures that must be followed to guarantee the accuracy of the preservation of
evidence and the accuracy of results concerning computer evidence processing.
What evidence is needed?
· All physical evidence (computer, peripherals, notepads, documentation, etc.)
· Visual output on the monitor
· Printed evidence on a printer
· Printed evidence on a plotter
· Film recorder (magnetic representations)
It is extremely important to realize that evidence must have been gathered in accordance with the
Fourth Amendment and the Electronic Communications Privacy Act (ECPA), and that
computer−generated evidence is considered "hearsay" with some exclusions. Depending on your
role or responsibility in the computer forensics investigation, you may be subject to differing sets of rules and regulations. Internal investigators, for example, are not subject to the Fourth Amendment stipulations; however, they are subject to the ECPA.
Typically, computer forensic tools exist in the form of computer software. Computer forensic
specialists guarantee accuracy of evidence processing results through the use of time−tested evidence processing procedures and through the use of multiple software tools, developed by separate and independent developers. The use of different tools that have been developed independently to validate results is important to avoid inaccuracies introduced by potential software design flaws and software bugs.
The introduction of the personal computer in 1981 and the resulting popularity came with a mixed blessing. Society in general benefited, but so did criminals using personal computers in the
commission of crimes. Today, personal computers are used in every facet of society to create and
share messages, compute financial results, transfer funds, purchase stocks, make airline
reservations, and access bank accounts and a wealth of worldwide information on essentially any
topic.
Computer forensics is used to identify evidence when personal computers are used in the
commission of crimes or in the abuse of company policies. Computer forensic tools and procedures are also used to identify computer security weaknesses and the leakage of sensitive computer data. In the past, documentary evidence was typically stored on paper and copies were made with carbon paper or photocopy machines.
Most documents are now stored on computer hard disk drives, floppy diskettes, Zip disks, and other forms of removable computer storage media. Computer forensics deals with finding, extracting, and documenting this form of "electronic" documentary evidence (www.forensics−intl.com/def4.html).
Along the way, prior to formally pursuing a cyber forensics investigation, several important and
critical questions must be asked:
What is the policy in the organization to report and deal with computer crime? (It may be
nonexistent, or it may be not well thought out or tested, or it may even be incompetent.)
·
· Do you "really" want to prosecute?
· Who do you call in law enforcement and what will be their reaction?
Additional questions that should be considered and appropriate answers well thought out include:
· Can you afford to be without the evidence?
· Are you willing to see this go public?
· Was a thorough investigation conducted?
· Did you violate the ECPA or any privacy issues?
· How will you prove the crime?
Is there any likelihood of the suspect doing damage prior to arrest? (Dr. Rayford Vaughn,
<vaughn@cs.msstate.edu>)
·
Obtaining concrete answers to these questions prior to embarking on a cyber forensics audit or
investigation is critical. Doing so may help shield the organization (as well as the
investigator/auditor/security personnel, etc.) from civil or criminal liabilities.
The material presented in the following pages of this field manual has been selected, developed,
and shared with the specific objective of providing the reader with a resource with which to become
better prepared to undertake and participate in the cyber forensics audit of a suspect system.
Table of Contents
Cyber Forensics—A Field Manual for Collecting, Examining, and Preserving Evidence of
Computer Crimes
Disclaimer...............6
Introduction......................7
Background.............8
Dimensions of the Problem..................9
Computer Forensics...........10
Works Cited.........11
Section I: Cyber Forensics
Chapter List..........13
Chapter 1: The Goal of the Forensic Investigation
Overview................................................................................................................................14
Why Investigate.....................................................................................................................14
Internet Exceeds Norm..........................................................................................................14
Inappropriate E−mail..............................................................................................................16
Non−Work−Related Usage of Company Resources.............................................................17
Theft of Information................................................................................................................18
Violation of Security Parameters............................................................................................18
Intellectual Property Infraction...............................................................................................19
Electronic Tampering.............................................................................................................20
Establishing a Basis or Justification to Investigate................................................................21
Determine the Impact of Incident...........................................................................................22
Who to Call/Contact...............................................................................................................24
If You Are the Auditor/Investigator.........................................................................................24
Resources..............................................................................................................................25
Authority.................................................................................................................................25
Obligations/Goals...................................................................................................................25
Reporting Hierarchy...............................................................................................................25
Escalation Procedures...........................................................................................................25
Time Frame............................................................................................................................26
Procedures.............................................................................................................................26
Precedence............................................................................................................................26
Independence........................................................................................................................26
Chapter 2: How to Begin a Non−Liturgical Forensic Examination
Overview................................................................................................................................27
Isolation of Equipment...........................................................................................................27
Cookies..................................................................................................................................29
Bookmarks.............................................................................................................................31
History Buffer.........................................................................................................................32
Cache.....................................................................................................................................34
Temporary Internet Files........................................................................................................35
Tracking of Logon Duration and Times..................................................................................35
Recent Documents List..........................................................................................................36
Tracking of Illicit Software Installation and Use.....................................................................37
Chapter 2: How to Begin a Non−Liturgical Forensic Examination
The System Review
The Manual Review...............................................................................................................41
Hidden Files...........................................................................................................................42
How to Correlate the Evidence..............................................................................................43
Works Cited......................................................................................................................44
Chapter 3: The Liturgical Forensic Examination:
Tracing Activity on a Windows−Based Desktop
Gathering Evidence For Prosecution Purposes.....................................................................45
Gathering Evidence Without Intent to Prosecute...................................................................45
The Microsoft Windows−Based Computer.............................................................................46
General Guidelines To Follow................................................................................................48
Cookies..................................................................................................................................50
Bookmarks/Favorites.............................................................................................................53
Internet Explorer's History Buffer...........................................................................................54
Temporary Storage on the Hard Drive...................................................................................55
Temporary Internet Files........................................................................................................56
System Registry.....................................................................................................................57
Enabling and Using Auditing via the Windows Operating System.........................................61
Confiscation of Computer Equipment....................................................................................65
Other Methods of Covert Monitoring......................................................................................66
Chapter 4: Basics of Internet Abuse:
What is Possible and Where to Look Under the Hood
Terms.....................................................................................................................................68
Types of Users.......................................................................................................................69
E−Mail Tracking.....................................................................................................................69
IP Address Construction........................................................................................................69
Browser Tattoos.....................................................................................................................69
How an Internet Search works...............................................................................................70
Swap Files.............................................................................................................................74
ISPs.......................................................................................................................................75
Servers...................................................................................................................................75
Works Cited......................................................................................................................75
Chapter 5: Tools of the Trade: Automated Tools
Used to Secure a System Throughout
the Stages of a Forensic Investigation
Overview................................................................................................................................77
Detection Tools......................................................................................................................77
Protection Tools.....................................................................................................................84
Analysis Tools........................................................................................................................87
Chapter 6: Network Intrusion Management and Profiling
Overview................................................................................................................................91
Common Intrusion Scenarios.................................................................................................91
Intrusion Profiling...................................................................................................................95
Creating the Profile................................................................................................................96
Conclusion...........................................................................................................................103
Chapter 7: Cyber Forensics and the Legal System
Overview..............................................................................................................................105
How the System Works........................................................................................................105
Issues of Evidence...............................................................................................................106
Hacker, Cracker, or Saboteur..............................................................................................108
Best Practices......................................................................................................................115
Notes..............................................................................................................................115
Acknowledgments..........................................................................................................116
Section II: Federal and International Guidelines
Chapter List...........117
References............118
Chapter 8: Searching and Seizing Computers
and Obtaining Electronic Evidence
Recognizing and Meeting Title III Concerns in Computer Investigations.............................123
Computer Records and the Federal Rules of Evidence.......................................................131
Proposed Standards for the Exchange of Digital Evidence.................................................134
Recovering and Examining Computer Forensic Evidence...................................................140
International Principles for Computer Evidence...................................................................141
Chapter 9: Computer Crime Policy and Programs
The National Infrastructure Protection Center Advisory 01−003..........................................143
The National Information Infrastructure Protection Act of 1996...........................................146
Distributed Denial of Service Attacks...................................................................................157
The Melissa Virus................................................................................................................163
Cybercrime Summit: A Law Enforcement/Information Technology Industry Dialogue........163
Chapter 10: International Aspects of Computer Crime
Council of Europe Convention on Cybercrime.....................................................................165
Council of Europe Convention on Cybercrime Frequently Asked Questions.......................168
Internet as the Scene of Crime............................................................................................168
Challenges Presented to Law Enforcement by High−Tech and Computer Criminals..........169
Problems of Criminal Procedural Law Connected with Information Technology.................169
Combating High−Tech and Computer−Related Crime........................................................169
Vienna International Child Pornography Conference...........................................................171
OECD Guidelines for Cryptography Policy..........................................................................171
Fighting Cybercrime: What are the Challenges Facing Europe?.........................................171
Chapter 11: Privacy Issues in the High−Tech Context
Law Enforcement Concerns Related to Computerized Databases......................................172
Enforcing the Criminal Wiretap Statute................................................................................174
Referring Potential Privacy Violations to the Department of Justice for Investigation
and Prosecution..................................................................................................................174
Testimony on Digital Privacy................................................................................................175
Chapter 12: Critical Infrastructure Protection
Attorney General Janet Reno's Speech on Critical Infrastructure Protection......................176
Protecting the Nation's Critical Infrastructures: Presidential Decision Directive 63.............176
The Clinton Administration's Policy on Critical Infrastructure Protection: Presidential
Chapter 12: Critical Infrastructure Protection
Decision Directive 63
Foreign Ownership Interests in the American Communications Infrastructure....................187
Carnivore and the Fourth Amendment.................................................................................188
Chapter 13: Electronic Commerce: Legal Issues
Overview..............................................................................................................................195
Guide for Federal Agencies on Implementing Electronic Processes...................................195
Consumer Protection in the Global Electronic Marketplace.................................................196
The Government Paperwork Elimination Act.......................................................................196
Internet Gambling................................................................................................................197
Sale of Prescription Drugs Over the Internet.......................................................................197
Guidance on Implementing the Electronic Signatures in Global And National
Commerce Act (E−SIGN)....................................................................................................198
Part I: General Overview of the E−SIGN Act.......................................................................198
The Electronic Frontier: the Challenge of Unlawful Conduct Involving the Use of the
Internet................................................................................................................................215
Internet Health Care Fraud..................................................................................................217
Jurisdiction in Law Suits.......................................................................................................218
Electronic Case Filing at the Federal Courts.......................................................................225
Notes..............................................................................................................................226
Chapter 14: Legal Considerations in Designing and Implementing Electronic
Processes: A Guide for Federal Agencies
Executive Summary.............................................................................................................229
Introduction..........................................................................................................................237
I. Why Agencies Should Consider Legal Risks....................................................................238
II. Legal Issues to Consider in "Going Paperless"...............................................................242
III. Reducing The Legal Risks in "Going Paperless"............................................................255
Conclusion...........................................................................................................................266
Notes..............................................................................................................................267
Chapter 15: Encryption
Department of Justice FAQ on Encryption Policy (April 24, 1998)......................................273
Interagency and State and Federal Law Enforcement Cooperation....................................273
Law Enforcement's Concerns Related to Encryption...........................................................273
Privacy in a Digital Age: Encryption and Mandatory Access...............................................274
Modification of H.R. 695.......................................................................................................280
Security and Freedom Through Encryption Act...................................................................281
OECD Guidelines for Cryptography Policy..........................................................................285
Recommended Reading................................................................................................285
Chapter 16: Intellectual Property
Prosecuting Intellectual Property Crimes Guidance............................................................286
Deciding Whether to Prosecute an Intellectual Property Case............................................286
Government Reproduction of Copyrighted Materials...........................................................286
Federal Statutes Protecting Intellectual Property Rights.....................................................286
IP Sentencing Guidelines.....................................................................................................289
Intellectual Property Policy and Programs...........................................................................292
Copyrights, Trademarks and Trade Secrets........................................................................294
Section III: Forensics Tools
Chapter List..............296
Chapter 17: Forensic and Security Assessment Tools
Detection, Protection, and Analysis.....................................................................................297
Detection and Prevention Tools for the PC Desktop...........................................................297
Analysis Tools......................................................................................................................299
Applications..........................................................................................................................301
Additional Free Forensics Software Tools...........................................................................307
Chapter 18: How to Report Internet−Related Crime
Overview..............................................................................................................................308
The Internet Fraud Complaint Center (IFCC)......................................................................309
Chapter 19: Internet Security: An Auditor's Basic Checklist
Firewalls...............................................................................................................................310
Supported Protocols............................................................................................................311
Anti−Virus Updates..............................................................................................................311
Software Management Systems..........................................................................................312
Backup Processes and Procedures.....................................................................................312
Intra−Network Security........................................................................................................312
Section IV: Appendices
Appendix List...........314
Appendix A: Glossary of Terms
A−C...........314
D..................317
E−G..................319
H−I.........................322
K−Q............................323
R−S........................................324
T−W..........................................326
Appendix B: Recommended Reading List
Books....................329
Articles........................332
Web Sites........................333
List of Exhibits
Chapter 2: How to Begin a Non−Liturgical Forensic Examination............337
Chapter 3: The Liturgical Forensic Examination:
Tracing Activity on a Windows−Based Desktop........337
Chapter 4: Basics of Internet Abuse:
What is Possible and Where to Look Under the Hood..............337
Chapter 5: Tools of the Trade: Automated Tools Used to
Secure a System Throughout the Stages of a Forensic Investigation..............338
Chapter 6: Network Intrusion Management and Profiling................338
Chapter 8: Searching and Seizing Computers and Obtaining Electronic Evidence.............338
List of Exhibits
Chapter 9: Computer Crime Policy and Programs........338
Chapter 11: Privacy Issues in the High−Tech Context.......338
Chapter 12: Critical Infrastructure Protection.....339
Chapter 13: Electronic Commerce: Legal Issues.........339
Chapter 14: Legal Considerations in Designing and Implementing Electronic
Processes: A Guide for Federal Agencies.........339
Chapter 18: How to Report Internet−Related Crime.......339