200-201 Network Intrusion Analysis Practice Question
A security analyst is investigating a suspected data exfiltration incident. Which TWO of the following indicators are most consistent with exfiltration over DNS?
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 responses with unusually large TXT record sizes
DNS exfiltration involves encoding data in subdomain queries, often with high entropy, and can use TXT records to retrieve data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
DNS responses with unusually large TXT record sizes
Why this is correct
Oversized TXT records can be used to deliver exfiltrated data.
- ✗
Large number of ICMP echo requests to external hosts
Why it's wrong here
ICMP is not DNS.
- ✗
Consistent traffic to a known C2 server on port 443
Why it's wrong here
That is HTTPS C2, not DNS exfiltration.
- ✗
Multiple failed HTTP POST requests to a file-sharing site
Why it's wrong here
That is over HTTP, not DNS.
- ✓
High volume of DNS queries to an unusual domain with random-looking subdomains
Why this is correct
Random subdomains suggest encoded data.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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