PrefacePrefaceOur Purpose and Approach
Welcome to the book named Real Digital Forensics. When we conceived this book, we wanted to give forensic investigators more than words to learn new skills. Many people express to us in our classes and speaking engagements a simple sentence we have heard hundreds of times: "How do I get into the field of computer forensics?" In our opinion, you cannot learn forensics unless you have hands-on practical experience. This brings up a more important question we usually hear next: "How do I get my hands on data to gain that experience?" This question is much more difficult to answer because the only data most people have to practice with comes from real casesand we all know that our clients do not want their data disseminated for learning tools! Therefore, it is difficult for most people to find data to practice with in order to sharpen their computer forensic skills. To answer this second question, we decided to publish this book with a DVD containing realistic evidence collected from several fictitious scenarios for the sole purpose of teaching the computer forensic tradecraft.
Most of the scenarios you will find throughout this book are very similar to types of cases that we investigate every day. We used the same tools attackers use when establishing a foothold in your network, the same methods rogue employees make use of to steal your trade secrets, and the same media we typically collect when we created the evidence files found on the DVD. Although we attempted to thoroughly investigate each company name we used for our scenarios, we want to state that none of this data was collected from computers within companies with coincidentally similar names or IP addresses.
The book begins by presenting methodologies used for the collection and analysis of computer forensic data. Then the book presents methods for compiling tool kits you can take with you to the scene of a computer-related crime. The book concludes by providing methodologies for deeper forensic analysis and solutions for when you run into other types of computer media such as USB memory and Palm devices.
Although computer forensic software tends to be commercially dominated, which means you would have to pay a hefty licensing fee just to get your feet wet, we wholeheartedly believe in open source because of the documented methodologies and availability of the source code. Reproducibility and documentation of methodologies is the cornerstone of any forensic science. Therefore, you will find that most techniques we recommend utilize a freely available and publicly documented toolset. This will enable you to examine the evidence found on the DVD without having to purchase additional software. When we do talk about commercial software to help round out your knowledge base, we will point it out in the text so that you are fully aware.
You will find that this book takes a practical, hands-on approach to solving problems that we frequently encounter when performing computer-related investigations. This book will not contain pages and pages about the theory of computer forensics. What it will contain are techniques you can employ immediately to solve your problems when performing an analysis. We hope you enjoy the Real Digital Forensics experience.
The Prerequisites and Target Audiences
Some of the techniques we discuss in this book are considered more advanced than common forensic knowledge. If you are just starting out in the computer forensic field, we suggest a basic understanding of computer forensics to more fully enjoy the content within this book. For an understanding of computer forensics that will help you work through the investigations throughout this book, we recommend you review the following publications:
The Tao of Network Security Monitoring: Beyond Intrusion Detection by Richard Bejtlich
Extrusion Detection: Security Monitoring for Internal Intrusions by Richard Bejtlich
Incident Response: Investigating Computer Crime by Kevin Mandia, Chris Prosise, and Matt Pepe
File System Forensic Analysis by Brian Carrier
Computer Forensics by Kruse, Warren and Jay Heiser
About the Art
Due to the complex nature of the data we discuss, some of our screenshots may appear small in this book and may be difficult to read.If you insert the DVD into a Windows machine, a new drive such as D: or E: will appear. If you insert the DVD into a Unix machine, you will need to mount the file system using the mount command, such as:
?mount /dev/cdrom /mnt/realdigitalforensics
Off of the DVD root directory, you will find another directory named after the scenario. Typically this directory has the same name as the victim company's name. For example, to find the "JBR Bank's Intrusion" scenario, you would navigate to the jbr_bank directory on the DVD. Within the scenario directory, you will find more subdirectories. Each subdirectory contains a particular type of evidence that the investigator collected. If the investigator acquired a forensic duplication, you can find the corresponding data in the forensic_duplication directory. If the responder performed a live response, the live_response directory will contain the relevant data, and so on.
Most of the data on the DVD is stored in native format. The live response data is plain text, memory dumps are binary files, and so on. When you want to examine a forensic duplication, you will notice that the files are compressed. This was done because the duplications can be up to 4 GB in size when they are uncompressed, which would not fit on a single DVD. Therefore, be warnedyou may want to have 10 to 20 GB of working room on your hard drive when you analyze this evidence. To analyze a forensic duplication, you must first copy the evidence from the DVD to your local hard drive and uncompress the duplication.We were forced, unfortunately, to perform some post processing so that we did not distribute copies of commercial software. Therefore, some system-related files on the victim machines containing the Windows operating system had zeros written over it. The original size of the file and directory structure we kept "as is" to simulate a real machine.
With that in mind, please load up your DVD and follow along with our many examples.
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You can't succeed in the field of computer forensics without hands-on practiceand you can't get hands-on practice without real forensic data. The solution: Real Digital Forensics. In this book, a team of world-class computer forensics experts walks you through six detailed, highly realistic investigations and provides a DVD with all the data you need to follow along and practice.
From binary memory dumps to log files, this DVD's intrusion data was generated by attacking live systems using the same tools and methods real-world attackers use. The evidence was then captured and analyzed using the same tools the authors employ in their own investigations. This book relies heavily on open source tools, so you can perform virtually every task without investing in any commercial software.
You'll investigate environments ranging from financial institutions to software companies and crimes ranging from intellectual property theft to SEC violations. As you move step by step through each investigation, you'll discover practical techniques for overcoming the challenges forensics professionals face most often.
Inside, you will find in-depth information on the following areas:
Responding to live incidents in both Windows and Unix environments
Determining whether an attack has actually occurred
Assembling a toolkit you can take to the scene of a computer-related crime
Analyzing volatile data, nonvolatile data, and files of unknown origin
Safely performing and documenting forensic duplications
Collecting and analyzing network-based evidence in Windows and Unix environments
Reconstructing Web browsing, e-mail activity, and Windows Registry changes
Tracing domain name ownership and the source of e-mails
Duplicating and analyzing the contents of PDAs and flash memory devices
The accompanying DVD contains several gigabytes of compressed data generated from actual intrusions. This data mirrors what analysts might find in real investigations and allows the reader to learn about forensic investigations in a realisticsetting.
© Copyright Pearson Education. All rights reserved.