CAS-004 Security Engineering Practice Question
An IoT device manufacturer wants to ensure the security of over-the-air (OTA) firmware updates. Which TWO measures are essential to protect the update process?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Sign the firmware with a trusted code signing certificate
Code signing ensures firmware integrity and authenticity. A secure boot chain verifies the signature before execution. Encrypting the firmware in transit protects confidentiality, but integrity is paramount. Hardcoding keys is insecure. Rolling back firmware can introduce vulnerabilities.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Sign the firmware with a trusted code signing certificate
Why this is correct
Digital signatures verify the firmware comes from a trusted source and has not been modified.
- ✗
Use a simple checksum for integrity verification
Why it's wrong here
Checksums are not cryptographically secure against tampering.
- ✓
Implement a secure boot chain that verifies the signature before applying the update
Why this is correct
Secure boot ensures only signed firmware can be loaded.
- ✗
Encrypt the firmware using a hardcoded key
Why it's wrong here
Hardcoded keys are insecure and can be extracted.
- ✗
Allow firmware downgrades to previous versions
Why it's wrong here
Downgrades can reintroduce vulnerabilities.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CAS-005 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CAS-005 exam.