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200-201 Practice Question: A host-based analysis tool reports that a file…
A host-based analysis tool reports that a file has a digital signature that is valid but from an untrusted publisher. What should the analyst interpret from this?
⚠ Common exam trap
Cisco often tests the distinction between signature validity (cryptographic integrity) and publisher trust (certificate chain trust), leading candidates to mistakenly equate a valid signature with safety or an untrusted publisher with guaranteed malice.
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
✓
The file may be malicious or legitimate; further analysis is needed
A valid digital signature confirms the file has not been tampered with since signing, but it does not guarantee the publisher is trustworthy. An untrusted publisher means the signing certificate is not in the system's trusted root store or has been flagged by a security policy, so the file could be either legitimate (e.g., from a new or self-signed publisher) or malicious (e.g., signed with a stolen certificate). Therefore, further analysis—such as checking the file's reputation, behavior, or origin—is required to determine its safety.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The file is definitely malicious because the publisher is untrusted
Why it's wrong here
An untrusted publisher means the certificate chain does not anchor to a trusted root; it does not confirm malicious intent, since legitimate vendors may use unrecognised certificates. Treating untrusted as malicious is tempting, but the correct interpretation is indeterminate risk requiring further investigation, not automatic condemnation.
- ✗
The file's signature was revoked
Why it's wrong here
A revoked certificate fails signature validation outright, so the tool would report the signature as invalid rather than valid. Revocation is tempting because it also concerns untrusted certificates, but revocation is checked separately via CRL or OCSP; here the signature verifies, only the publisher's trust status is unknown.
- ✓
The file may be malicious or legitimate; further analysis is needed
Why this is correct
A valid signature only proves the file was signed and not altered since signing; it does not vouch for the signer's trustworthiness. Since the publisher is untrusted, reputation and behaviour must be assessed before judging intent, so the file could be either benign or malicious.
- ✗
The file is definitely safe because the signature is valid
Why it's wrong here
A valid signature only proves the file is unaltered since signing and that the signer holds the private key; it says nothing about the publisher's trustworthiness or the file's intent. Trusting validity as safety is tempting, but untrusted publishers can sign malware, so further reputation analysis is required.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-201 practice question is part of Courseiva's free Cisco 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 200-201 exam.