mediummultiple choiceObjective-mapped

A penetration tester is testing a web application that uses JSON Web Tokens (JWTs) for authentication. The tester discovers that the server does not verify the JWT signature properly. The tester crafts a JWT with an arbitrary payload and sets the algorithm to 'none'. Which attack does this enable?

Question 1mediummultiple choice
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A penetration tester is testing a web application that uses JSON Web Tokens (JWTs) for authentication. The tester discovers that the server does not verify the JWT signature properly. The tester crafts a JWT with an arbitrary payload and sets the algorithm to 'none'. Which attack does this enable?

Answer choices

Why each option matters

Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.

A

Distractor review

SQL injection

The JWT signature flaw does not involve database query manipulation; it targets authentication logic.

B

Distractor review

Server-side request forgery

SSRF exploits server-side requests to internal resources, not JWT token verification.

C

Best answer

Authentication bypass

Setting the algorithm to 'none' and forging the token allows the attacker to bypass authentication and gain unauthorized access.

D

Distractor review

Cross-site request forgery

CSRF tricks a user into making unintended requests; it does not exploit JWT signature verification.

Common exam trap

Common exam trap: NAT rules depend on direction and matching traffic

NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.

Technical deep dive

How to think about this question

NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.

KKey Concepts to Remember

  • Static NAT maps one inside address to one outside address.
  • PAT allows many inside hosts to share one public address using ports.
  • Inside local and inside global describe the private and translated addresses.
  • NAT ACLs identify traffic for translation, not always security filtering.

TExam Day Tips

  • Identify inside and outside interfaces first.
  • Check whether the scenario needs static NAT, dynamic NAT or PAT.
  • Do not confuse NAT matching ACLs with normal packet-filtering intent.

Related practice questions

Related PT0-002 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

More questions from this exam

Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.

FAQ

Questions learners often ask

What does this PT0-002 question test?

Static NAT maps one inside address to one outside address.

What is the correct answer to this question?

The correct answer is: Authentication bypass — The 'none' algorithm in JWT allows an attacker to forge tokens without a valid signature because the server skips signature verification. This directly leads to authentication bypass, enabling the attacker to impersonate any user. Other attack types like SQL injection, SSRF, or CSRF are not directly enabled by this JWT flaw.

What should I do if I get this PT0-002 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.

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