CompTIA CS0-003 Exam - 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

Limited Time Offer

25%

Off

Get Premium CS0-003 Questions as Interactive Web-Based Practice Test or PDF

Contribute your Thoughts:

Submit Cancel

Jettie

5 months ago

Not sure about this, feels like there could be more to it.

upvoted 0 times

...

Herman

5 months ago

D could also be a possibility, but B seems stronger.

upvoted 0 times

...

Elly

5 months ago

Looks like B is the most likely scenario.

upvoted 0 times

...

Carmen

6 months ago

Totally agree, B makes the most sense here.

upvoted 0 times

...

Lyla

6 months ago

Wait, how can DKIM fail if SPF passed?

upvoted 0 times

...

Angella

6 months ago

I recall that a PASS on SPF means it came from an authorized server, but the DKIM and DMARC fails are throwing me off. Maybe it was just not signed?

upvoted 0 times

...

Mabelle

6 months ago

I'm a bit confused about the options. Could it be that the email security software just didn't process everything correctly? That seems plausible.

upvoted 0 times

...

Elza

7 months ago

This question feels familiar; I think I practiced something similar. If DKIM fails, it could mean the email wasn't sent from an authorized server, right?

upvoted 0 times

...

Myra

7 months ago

I remember studying SPF, DKIM, and DMARC, but I'm not entirely sure how they interact. I think a DKIM fail usually means the email wasn't signed properly?

upvoted 0 times

...

Torie

7 months ago

Okay, I think I've got this. The SPF pass means the server is authorized, but the DKIM and DMARC fails suggest the message wasn't properly signed. That points to option B, the message was sent from an authorized server but wasn't signed.

upvoted 0 times

...

Toshia

7 months ago

This is a tough one. The SPF pass tells me the server is legit, but the DKIM and DMARC fails make me think there's an issue with the email security software. I'm going to go with option D and hope for the best.

upvoted 0 times

...

Jaleesa

7 months ago

I'm a bit confused here. The SPF pass indicates the server is authorized, but the DKIM and DMARC fails make me wonder if there's an insider threat trying to mask something. I'm not sure, maybe option A?

upvoted 0 times

...

Gladys

8 months ago

Okay, let me think this through. If the SPF passed, that means the email came from an authorized server. But the DKIM and DMARC failures suggest there's something off with the message. I'm leaning towards option D, the email security software didn't process the records correctly.

upvoted 0 times

...

Martina

8 months ago

Hmm, this one seems tricky. The SPF pass but DKIM and DMARC fail makes me think the message was sent from an authorized server but wasn't properly signed. I'll go with option B.

upvoted 0 times

...

Bobbye

1 year 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.

upvoted 0 times

Kerry

12 months ago

I wonder if the IT guy likes pizza too.

upvoted 0 times

...

Nguyet

1 year ago

Definitely, a slice would hit the spot right now.

upvoted 0 times

...

Garry

1 year ago

Yeah, that makes sense. Maybe they should order that pizza after all.

upvoted 0 times

...

Adell

1 year ago

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

upvoted 0 times

...

Leonida

1 year 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?

upvoted 0 times

Chaya

1 year ago

User 2: Yeah, that sounds like the most likely scenario. The analyst must have been relieved!

upvoted 0 times

...

Quiana

1 year ago

User 1: I think the email was sent from an authorized server but wasn't signed.

upvoted 0 times

...

Lazaro

1 year ago

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

upvoted 0 times

...

Tracey

1 year 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.

upvoted 0 times

...

Lauran

1 year 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.

upvoted 0 times

...

Marva

1 year ago

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

upvoted 0 times

...

Pearline

1 year ago

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

upvoted 0 times

...

Tashia

1 year 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.

upvoted 0 times