200-201 Network Intrusion Analysis Practice Question
During an incident, an analyst observes the following in PCAP: (1) DNS queries with random-looking subdomains to a known malicious domain, (2) large outbound FTP transfers of .zip files, (3) HTTP POST requests with Base64-encoded data in the body. Which THREE exfiltration techniques are being used? (Select 3)
⚠ Common exam trap
A common mix-up: candidates confuse exfiltration techniques with obfuscation techniques (like steganography) or assume ICMP is always used for covert channels, when the question specifically describes DNS, FTP, and HTTP artifacts.
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
✓
FTP exfiltration
Option B (FTP exfiltration) is correct because the PCAP shows large outbound FTP transfers of .zip files, which is a classic data exfiltration pattern where stolen data is archived and sent over FTP to an external server. Option C (DNS tunneling) is correct because DNS queries with random-looking subdomains to a known malicious domain indicate data being encoded into DNS query names and sent to an attacker-controlled authoritative DNS server, a hallmark of DNS tunneling. Option E (HTTP exfiltration via POST) is correct because HTTP POST requests carrying Base64-encoded data in the body are a common method of covertly exfiltrating data through web traffic that blends in with normal HTTP. Option A (ICMP exfiltration) does not belong because no ICMP echo request/reply traffic with embedded payloads is described in the PCAP. Option D (Steganography) does not belong because steganography involves hiding data inside other files such as images or audio, and no such carrier files or hidden-content artifacts are mentioned in the observed traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ICMP exfiltration
Why it's wrong here
No ICMP traffic appears in the capture; the observed channels are DNS tunnelling, FTP transfer and HTTP POST. ICMP exfiltration is tempting as a covert channel, and would be correct if echo request payloads carried encoded data to an external host.
- ✓
FTP exfiltration
Why this is correct
FTP exfiltration matches the large outbound transfers of .zip files, since FTP carries bulk file data over dedicated control and data channels. This satisfies the stem's second observation directly, distinguishing it from DNS tunnelling and HTTP POST encoding, which handle covert or encoded channels rather than straightforward bulk archive transfer.
- ✓
DNS tunneling
Why this is correct
Data in DNS queries.
- ✗
Steganography
Why it's wrong here
Steganography hides data inside image, audio or video carriers, leaving no Base64 HTTP body or FTP archive in the capture. It is tempting because it is a genuine exfiltration channel, and would be correct had the analyst found altered media files rather than encoded POST payloads.
- ✓
HTTP exfiltration (POST)
Why this is correct
HTTP POST requests carrying Base64-encoded data match the third PCAP observation, where stolen content is tunnelled inside request bodies to blend with legitimate web traffic. This satisfies the stem's HTTP POST constraint, distinguishing application-layer exfiltration from the DNS tunnelling and FTP transfer also present.
Visual reference
Go deeper
Related to this question
About these practice questions
Courseiva writes every 200-201 question from scratch — 968 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.