CompTIA Exam CS0-003 Topic 2 Question 41 Discussion

Actual exam question for CompTIA's CS0-003 exam

Question #: 41
Topic #: 2

A security analyst reviews a SIEM alert related to a suspicious email and wants to verify the authenticity of the message:

SPF = PASS

DKIM = FAIL

DMARC = FAIL

Which of the following did the analyst most likely discover?

AAn insider threat altered email security records to mask suspicious DNS resolution traffic.

BThe message was sent from an authorized mail server but was not signed.

CLog normalization corrupted the data as it was brought into the central repository.

DThe email security software did not process all of the records correctly.

Show Suggested Answer

Suggested Answer: B

Comprehensive and Detailed Step-by-Step The SPF = PASS result confirms the email came from an authorized server, but DKIM = FAIL indicates the message was not properly signed with the expected DomainKeys Identified Mail (DKIM) signature. DMARC = FAIL suggests that because DKIM failed, the overall email authentication failed. This scenario is consistent with a legitimate server sending an unsigned email.

CompTIA CySA+ All-in-One Guide (Chapter 5: Email Analysis)

CompTIA CySA+ Practice Tests (Domain 1.3 Email Authentication)

by Kenneth at Mar 24, 2025, 06:22 AM

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Bobbye

7 days ago

You know, I bet the analyst was just sitting there, staring at the screen, wondering if they should call the IT guy or order a pizza. Option B is the winner, but I could go for a slice right about now.

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Leonida

8 days ago

Haha, the analyst must have been like, 'Wait, is this a real alert or just a prank?' Option B is the way to go, but where's the fun in that?

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Lazaro

9 days ago

Alright, let's see... SPF passes, DKIM fails, DMARC fails. Sounds like an authorized server but a missing signature. Option B it is!

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Tracey

10 days ago

Oh man, I bet the analyst was sweating bullets trying to figure this one out. Option B seems like the clear choice, but you never know with these tricky security questions.

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Lauran

11 days ago

You know, I bet the security analyst is kicking themselves for not double-checking the email logs. Option D is probably the way to go here.

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Marva

12 days ago

I believe the answer is B, as SPF passing and DKIM/DMARC failing points to lack of proper email authentication.

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Pearline

14 days ago

Could it be that the email security software did not process all of the records correctly?

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Tashia

19 days ago

Hmm, if the SPF passed but the DKIM and DMARC failed, it seems like the message was sent from an authorized server but not properly signed. Option B seems the most likely.

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Jamal

3 days ago

I agree, it does seem like the message was sent from an authorized server but not properly signed.

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Devora

24 days ago

I agree with Lavina, DKIM and DMARC failing indicates lack of proper email signing.

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Lavina

25 days ago

I think the analyst discovered that the message was sent from an authorized mail server but was not signed.

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