200-201 Network Intrusion Analysis Practice Question
An analyst observes a series of DNS queries for subdomains like 'ZGVzdGluYXRpb24= .malicious.com' where the subdomain part appears base64-encoded. The volume of DNS traffic from a single host is unusually high. Which exfiltration technique is most likely in use?
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
✓
DNS tunnelling
DNS exfiltration encodes data in subdomain queries to bypass traditional monitoring.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
FTP exfiltration
Why it's wrong here
FTP uses file transfers, not DNS queries.
- ✓
DNS tunnelling
Why this is correct
Encoded data in DNS subdomain queries is a hallmark of DNS tunnelling/exfiltration.
- ✗
HTTP POST exfiltration
Why it's wrong here
HTTP POST uses HTTP protocol, not DNS queries.
- ✗
Steganography in images
Why it's wrong here
Steganography hides data in media files, not DNS queries.
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JA
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.