CND Application And Data Protection Practice Question
An enterprise application developer is implementing JSON Web Tokens (JWT) for stateless session authentication. Which implementation flaw represents the highest risk of signature forgery and unauthorized privilege escalation?
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
✓
Failing to strictly validate the JWT algorithm header, allowing 'none' or asymmetric-to-symmetric key confusion (RS256 to HS256)
Accepting 'none' as a valid algorithm or failing to verify the cryptographic signature (e.g., confusing RS256 with HS256 where the public key is treated as the HMAC secret) allows attackers to forge arbitrary JWT payloads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Setting an expiration time (exp claim) of 15 minutes
Why it's wrong here
Short token lifespans reduce the window of opportunity if a token is compromised.
- ✓
Failing to strictly validate the JWT algorithm header, allowing 'none' or asymmetric-to-symmetric key confusion (RS256 to HS256)
Why this is correct
Allowing 'none' algorithms or key confusion attacks enables attackers to forge valid signatures for any administrative user ID.
- ✗
Storing the JWT inside an HTTP-only Secure cookie instead of localStorage
Why it's wrong here
Storing JWTs in HTTP-only Secure cookies is a security best practice that prevents XSS theft, not a flaw.
- ✗
Including the user's role claim inside the public payload section
Why it's wrong here
Claims in JWT payloads are readable by anyone because base64url encoding is not encryption, but role claims themselves do not cause signature forgery.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official EC-Council exam blueprint
This CND practice question is part of Courseiva's free EC-Council 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 CND exam.