If you’re planning on taking the Security+ exam, chain of custody is an important topic for the exam. This post should help on having a basic understanding of it.
For example, can you answer this question?
Q. A security analyst tagged a computer stating when he took possession of it. What is the BEST explanation for this?
A. To calculate time offset
B. To ensure the system is decommissioned
C. To begin a chain of custody
D. To implement separation of duties
More, do you know why the correct answer is correct and the incorrect answers are incorrect? Answer and explanation at end of this post.
Performing a Forensic Evaluation
A forensic evaluation helps the organization collect and analyze data as evidence it can use in the prosecution of a crime. In general, forensic evaluations proceed with the assumption that the data collected will be used as evidence in court. Because of this, forensic practices protect evidence to prevent modification and control evidence after collecting it.
Once the incident has been contained or isolated, the next step is a forensic evaluation. What do you think of when you hear forensics? Many people think about the TV program CSI (short for “crime scene investigation”) and all of its spin-offs. These shows demonstrate the phenomenal capabilities of science in crime investigations.
Computer forensics analyzes evidence from computers to determine details on computer incidents, similar to how CSI personnel analyze evidence from crime scenes. It uses a variety of different tools to gather and analyze computer evidence. Computer forensics is a growing field, and many educational institutions offer specialized degrees around the science. Although you may not be the computer forensics expert analyzing the evidence, you should know about some of the basic concepts related to gathering and preserving the evidence.
Forensic experts use a variety of forensic procedures to collect and protect data after an attack. A key part of this process is preserving the evidence. In other words, they ensure that they don’t modify the data as they collect it, and they protect it after collection. A rookie cop wouldn’t walk through a pool of blood at a crime scene, at least not more than once. Similarly, employees shouldn’t access systems that have been attacked or power them down.
For example, files have properties that show when they were last accessed. However, in many situations, accessing the file modifies this property. This can prevent an investigation from identifying when an attacker accessed the file. Additionally, data in a system’s memory includes valuable evidence, but turning a system off deletes this data. In general, first responders do not attempt to analyze evidence until they have taken the time to collect and protect it.
Forensic experts have specialized tools they can use to capture data. For example, many experts use EnCase by Guidance Software or Forensic Toolkit by AccessData. These tools can capture data from memory or disks. This includes documents, images, email, webmail, Internet artifacts, web history, chat sessions, compressed files, backup files, and encrypted files. They can also capture data from smartphones and tablets.
The 601 Version of the Study Guide
The CompTIA Security+: Get Certified Get Ahead: SY0-601 Study GuideEach of the eleven chapters presents topics in an easy to understand manner and includes real-world examples of security principles in action.
You’ll understand the important and relevant security topics for the Security+ exam, without being overloaded with unnecessary details. Additionally, each chapter includes a comprehensive review section to help you focus on what’s important.
Over 300 realistic practice test questions with in-depth explanations will help you test your comprehension and readiness for the exam. The book includes:
- A 75 question pre-test
- A 75 question post-test
- Practice test questions at the end of every chapter.
Each practice test question includes a detailed explanation to help you understand the content and the reasoning behind the question. You’ll be ready to take and pass the exam the first time you take it.
If you plan to pursue any of the advanced security certifications, this guide will also help you lay a solid foundation of security knowledge. Learn this material, and you’ll be a step ahead for other exams. This SY0-601 study guide is for any IT or security professional interested in advancing in their field, and a must-read for anyone striving to master the basics of IT security.
Chain of Custody as a Process
A key part of incident response is collecting and protecting evidence. A chain of custody is a process that provides assurances that evidence has been controlled and handled properly after collection. Forensic experts establish a chain of custody when they first collect evidence.
Security professionals use a chain-of-custody form to document this control. The chain-of-custody form provides a record of every person who was in possession of a physical asset collected as evidence. It shows who had custody of the evidence and where it was stored the entire time since collection. Additionally, personnel often tag the evidence as part of a chain-of-custody process. A proper chain-of-custody process ensures that evidence presented in a court of law is the same evidence that security professionals collected.
As an example, imagine that Homer collected a hard drive as part of an investigation. However, instead of establishing a chain of custody, he simply stores the drive on his desk with the intention of analyzing it the next day. Is it possible that someone could modify the contents of the drive overnight? Absolutely. Instead, he should immediately establish a chain of custody and lock the drive in a secure storage location.
If evidence is not controlled, someone can modify, tamper, or corrupt it. Courts will rule the evidence inadmissible if there is a lack of adequate control, or even a lack of documentation showing that personnel maintained adequate control. However, the chain of custody provides proof that personnel handled the evidence properly.
Remember this
A chain of custody provides assurances that evidence has been controlled and handled properly after collection. It documents who handled the evidence and when they handled it.
Q. A security analyst tagged a computer stating when he took possession of it. What is the BEST explanation for this?
A. To calculate time offset
B. To ensure the system is decommissioned
C. To begin a chain of custody
D. To implement separation of duties
Answer is C. A chain of custody identifies who controlled evidence after it was confiscated. It can start with a tag when a person collects the evidence. Security analysts later create a chain-of-custody log to detail who controlled the evidence at different times.
Time offset is related to different time zones or times recorded on a video recorder.
A security analyst would confiscate a computer to analyze it, not decommission it.
Separation of duties is related to people, not computers.
You might also like to view an example of Security+ Forensic Performance Based Question.
