Why forensics preserves evidence in Cybersecurity - See It in Action

Why Forensics Preserves Evidence

📖 Scenario: You are working as a cybersecurity trainee. Your task is to understand how digital forensics preserves evidence during an investigation. This helps ensure that the evidence remains trustworthy and can be used in court or to solve a case.

🎯 Goal: Build a simple Python dictionary that lists reasons why forensics preserves evidence. Then, add a condition to filter important reasons. Finally, create a summary list of these reasons to understand their importance.

📋 What You'll Learn

Create a dictionary called evidence_reasons with exact keys and values

Add a variable called important_threshold with the value 3

Use a dictionary comprehension to create important_reasons with reasons having values greater or equal to important_threshold

Create a list called summary containing only the keys from important_reasons

💡 Why This Matters

🌍 Real World

Digital forensics experts must carefully preserve evidence to ensure it is reliable and admissible in legal cases.

💼 Career

Understanding evidence preservation is essential for cybersecurity professionals working in incident response and forensic analysis.

1

Create the evidence reasons dictionary

Create a dictionary called evidence_reasons with these exact entries: 'Integrity': 5, 'Chain of Custody': 4, 'Authentication': 3, 'Analysis': 2, 'Presentation': 1.

Cybersecurity

# Create the evidence_reasons dictionary with exact entries
# Your code here

Hint

Use curly braces to create a dictionary with the exact keys and values.

2

Add the important threshold variable

Add a variable called important_threshold and set it to the integer 3.

Cybersecurity

evidence_reasons = {
    'Integrity': 5,
    'Chain of Custody': 4,
    'Authentication': 3,
    'Analysis': 2,
    'Presentation': 1
}
# Add the important_threshold variable below
# Your code here

Hint

Just create a variable and assign the number 3 to it.

3

Filter important reasons using dictionary comprehension

Use a dictionary comprehension to create a new dictionary called important_reasons that includes only the items from evidence_reasons where the value is greater than or equal to important_threshold.

Cybersecurity

evidence_reasons = {
    'Integrity': 5,
    'Chain of Custody': 4,
    'Authentication': 3,
    'Analysis': 2,
    'Presentation': 1
}
important_threshold = 3
# Create important_reasons dictionary using comprehension
# Your code here

Hint

Use {key: value for key, value in dict.items() if condition} syntax.

4

Create a summary list of important reasons

Create a list called summary that contains only the keys from the important_reasons dictionary.

Cybersecurity

evidence_reasons = {
    'Integrity': 5,
    'Chain of Custody': 4,
    'Authentication': 3,
    'Analysis': 2,
    'Presentation': 1
}
important_threshold = 3
important_reasons = {reason: score for reason, score in evidence_reasons.items() if score >= important_threshold}
# Create summary list with keys from important_reasons
# Your code here

Hint

Use the keys() method and convert it to a list.

Practice

1. Why is it important for forensic experts to preserve evidence without altering it?

easy

A. To make the evidence look more impressive

B. To ensure the evidence remains reliable and trustworthy in court

C. To speed up the investigation process

D. To allow anyone to change the evidence if needed

Solution

1. Step 1: Understand the role of evidence in forensics

   Evidence must be reliable to prove facts in legal cases.

2. Step 2: Recognize the importance of preserving evidence unchanged

   Changing evidence can make it unreliable and unusable in court.

3. Final Answer:

   To ensure the evidence remains reliable and trustworthy in court -> Option B

4. Quick Check:

   Preserving evidence = Trustworthy proof [OK]

Hint: Evidence must stay unchanged to be trusted [OK]

Common Mistakes:

• Thinking evidence can be altered to improve it
• Believing speed is more important than accuracy
• Assuming evidence can be changed by anyone

2. Which of the following is the correct first step when collecting digital evidence in forensics?

easy

A. Document the scene and evidence before touching anything

B. Turn off the device immediately to prevent data loss

C. Delete unnecessary files to reduce clutter

D. Share the evidence with others before analysis

Solution

1. Step 1: Identify proper evidence collection procedure

   Documenting the scene preserves context and chain of custody.

2. Step 2: Understand why documentation comes before handling

   It prevents loss of important details and maintains evidence integrity.

3. Final Answer:

   Document the scene and evidence before touching anything -> Option A

4. Quick Check:

   Document first = Preserve context [OK]

Hint: Always document before touching evidence [OK]

Common Mistakes:

• Turning off devices without documentation
• Deleting files thinking it helps
• Sharing evidence too early

3. Consider this scenario: A forensic investigator copies data from a suspect's computer using a write-blocker device. What is the main reason for using a write-blocker?

medium

A. To speed up the copying process

B. To encrypt the copied data for security

C. To prevent any changes to the original data during copying

D. To delete unnecessary files automatically

Solution

1. Step 1: Understand the function of a write-blocker

   A write-blocker stops any write commands to the original device.

2. Step 2: Recognize why preventing changes is critical

   It keeps the original evidence unchanged and admissible in court.

3. Final Answer:

   To prevent any changes to the original data during copying -> Option C

4. Quick Check:

   Write-blocker = No changes to original data [OK]

Hint: Write-blockers stop changes to original evidence [OK]

Common Mistakes:

• Thinking write-blockers speed up copying
• Believing they delete files
• Confusing with encryption tools

4. A forensic analyst accidentally modifies a file timestamp while copying evidence. What is the best way to fix this mistake?

medium

A. Re-collect the evidence using proper write-blocking tools

B. Manually change the timestamp back to original

C. Ignore it since the file content is unchanged

D. Delete the file and use a backup copy

Solution

1. Step 1: Identify the problem caused by modifying evidence

   Changing timestamps can question evidence integrity in court.

2. Step 2: Determine the correct corrective action

   Re-collecting with write-blockers ensures no changes happen again.

3. Final Answer:

   Re-collect the evidence using proper write-blocking tools -> Option A

4. Quick Check:

   Use write-blockers to avoid evidence changes [OK]

Hint: Re-collect evidence properly if altered [OK]

Common Mistakes:

• Ignoring timestamp changes
• Trying to manually fix timestamps
• Deleting files without proper backup

5. During a forensic investigation, why must the chain of custody be carefully documented and preserved along with the evidence?

hard

A. To make the evidence easier to delete after the case

B. To allow investigators to share evidence freely with the public

C. To speed up the investigation by skipping detailed reports

D. To prove that the evidence was handled properly and not tampered with

Solution

1. Step 1: Understand the purpose of chain of custody

   It records who handled the evidence and when, ensuring accountability.

2. Step 2: Recognize why this documentation is critical

   It proves evidence was not altered or tampered with during the investigation.

3. Final Answer:

   To prove that the evidence was handled properly and not tampered with -> Option D

4. Quick Check:

   Chain of custody = Proof of proper handling [OK]

Hint: Chain of custody proves evidence integrity [OK]

Common Mistakes:

• Thinking chain of custody is for public sharing
• Skipping documentation to save time
• Using it to delete evidence