Threat modeling (STRIDE, DREAD) in Cybersecurity - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding STRIDE Categories

Which of the following correctly matches a STRIDE category with its primary threat type?

A Repudiation - Denying actions or transactions

B Information Disclosure - Exposing sensitive information

C Tampering - Modifying data without authorization

D Spoofing - Pretending to be someone else to gain unauthorized access

💡 Hint

Think about what each STRIDE letter stands for and the kind of threat it represents.

Spoofing means pretending to be someone else to gain access. Tampering is about modifying data. Repudiation involves denying actions, and Information Disclosure is about exposing data.

📋 Factual

intermediate

DREAD Risk Assessment Components

Which component of the DREAD model evaluates how easily an attacker can exploit a vulnerability?

A Exploitability

B Reproducibility

C Damage Potential

D Discoverability

💡 Hint

Consider which factor measures the effort or skill needed to carry out an attack.

Exploitability measures how easy it is for an attacker to exploit a vulnerability. Damage Potential is about impact, Reproducibility about repeating the attack, and Discoverability about finding the vulnerability.

🚀 Application

advanced

Applying STRIDE to a Scenario

A web application allows users to upload files without checking the file type. Which STRIDE threat does this vulnerability most directly relate to?

A Tampering

B Information Disclosure

C Elevation of Privilege

D Spoofing

💡 Hint

Think about what an attacker could do by uploading malicious files.

Uploading unchecked files can allow attackers to modify or inject malicious data, which is Tampering. Elevation of Privilege is about gaining higher access, Information Disclosure about leaking data, and Spoofing about impersonation.

🔍 Analysis

advanced

Interpreting DREAD Scores

A vulnerability has the following DREAD scores: Damage Potential=8, Reproducibility=7, Exploitability=9, Affected Users=6, Discoverability=5. What is the average risk score?

A 7.5

B 7

C 7.0

D 8

💡 Hint

Calculate the average by adding all scores and dividing by the number of components.

The sum is 8+7+9+6+5=35. Dividing by 5 gives 7.0 as the average risk score.

❓ Reasoning

expert

Choosing the Correct STRIDE Threat for a Given Attack

An attacker intercepts and reads sensitive data sent between a user and a server without altering it. Which STRIDE threat does this represent?

A Denial of Service

B Information Disclosure

C Repudiation

D Tampering

💡 Hint

Focus on what the attacker does with the data.

Intercepting and reading data without changing it is Information Disclosure. Tampering involves modification, Repudiation is denying actions, and Denial of Service is about blocking access.

Practice

1. What is the main purpose of threat modeling in cybersecurity?

easy

A. To identify and prioritize potential security risks before they happen

B. To write code faster

C. To design user interfaces

D. To monitor network traffic in real-time

Solution

1. Step 1: Understand the goal of threat modeling

   Threat modeling is used to find security risks early in a system or application.

2. Step 2: Identify the main benefit

   It helps prioritize which risks to fix first to prevent harm.

3. Final Answer:

   To identify and prioritize potential security risks before they happen -> Option A

4. Quick Check:

   Threat modeling = find and rank risks [OK]

Hint: Threat modeling = find risks early and rank them [OK]

Common Mistakes:

• Confusing threat modeling with coding or UI design
• Thinking it monitors live traffic
• Assuming it fixes risks automatically

2. Which of the following correctly lists categories from the STRIDE threat model?

easy

A. Security, Trust, Reliability, Integrity, Data, Encryption

B. Scanning, Testing, Reporting, Investigating, Defending, Encrypting

C. Spoofing, Testing, Reporting, Information, Denial, Elevation

D. Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege

Solution

1. Step 1: Recall STRIDE categories

   STRIDE stands for Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege.

2. Step 2: Match options to STRIDE

   Only Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege lists all correct STRIDE categories in full.

3. Final Answer:

   Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege -> Option D

4. Quick Check:

   STRIDE = STRIDE categories [OK]

Hint: STRIDE is an acronym for six threat types [OK]

Common Mistakes:

• Mixing unrelated security terms
• Partial or incorrect category names
• Assuming STRIDE includes testing or encryption

3. Given a threat scored in DREAD as follows: Damage potential=3, Reproducibility=2, Exploitability=4, Affected users=3, Discoverability=1. What is the total DREAD score?

medium

A. 13

B. 12

C. 10

D. 9

Solution

1. Step 1: Add all DREAD components

   Sum the scores: 3 + 2 + 4 + 3 + 1 = 13.

2. Step 2: Verify calculation

   Check each value carefully to avoid mistakes.

3. Final Answer:

   13 -> Option A

4. Quick Check:

   Sum of DREAD scores = 13 [OK]

Hint: Add all five DREAD scores to get total [OK]

Common Mistakes:

• Forgetting one category in sum
• Adding incorrectly
• Confusing DREAD with STRIDE categories

4. A security analyst uses STRIDE but mistakenly includes 'Encryption' as a category. What is the error in this approach?

medium

A. Encryption is part of STRIDE under Denial of Service

B. Encryption is not a STRIDE threat category; it is a security control

C. Encryption is a DREAD scoring factor

D. Encryption is a type of Repudiation threat

Solution

1. Step 1: Understand STRIDE categories

   STRIDE categories are specific threat types, not security controls.

2. Step 2: Identify role of encryption

   Encryption is a defense method, not a threat category.

3. Final Answer:

   Encryption is not a STRIDE threat category; it is a security control -> Option B

4. Quick Check:

   Encryption = control, not STRIDE threat [OK]

Hint: STRIDE lists threats, not defenses like encryption [OK]

Common Mistakes:

• Confusing security controls with threat categories
• Mixing STRIDE and DREAD concepts
• Assuming encryption causes threats

5. You have two threats: Threat A with DREAD scores (Damage=5, Reproducibility=3, Exploitability=4, Affected Users=2, Discoverability=3) and Threat B with scores (Damage=4, Reproducibility=4, Exploitability=3, Affected Users=5, Discoverability=2). Which threat should be fixed first based on DREAD, and why?

hard

A. Threat B, because it has higher reproducibility

B. Threat A, because its total DREAD score is higher indicating greater risk

C. Threat B, because it has the higher total DREAD score indicating greater risk

D. Threat A, because it has higher damage potential only

Solution

1. Step 1: Calculate total DREAD scores for both threats

   Threat A: 5+3+4+2+3=17; Threat B: 4+4+3+5+2=18.

2. Step 2: Compare total scores and interpret

   Threat B has a higher total score (18) than Threat A (17), so Threat B is higher risk.

3. Step 3: Re-examine options carefully

   Threat A, because its total DREAD score is higher indicating greater risk incorrectly states Threat A has higher score. Options C and D focus on single factors instead of total score.

4. Final Answer:

   Threat B, because it has the higher total DREAD score indicating greater risk -> Option C

5. Quick Check:

   Total DREAD score guides priority [OK]

Hint: Sum DREAD scores; higher total means higher priority [OK]

Common Mistakes:

• Choosing based on one factor only
• Misadding scores
• Ignoring total DREAD score