220-1202 Security Practice Question
An administrator receives an alert that a workstation is repeatedly making DNS queries for random-looking domain names and sending small amounts of data to external IP addresses every few minutes. The endpoint protection agent is installed and up to date, and no user is logged in. Which of the following is the MOST likely explanation for this behavior?
⚠ Common exam trap
The trap here is dismissing the traffic as routine update or synchronization noise because it is small and periodic, when random domain names plus frequent small transfers are the signature of DNS tunneling.
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 workstation is infected with malware that uses DNS tunneling for command and control.
Malware that has established a foothold often uses DNS tunneling to evade egress filtering, encoding command-and-control traffic in DNS queries and responses. The combination of randomized domain names, a repeating short interval, small outbound data, and no interactive user strongly indicates a compromised endpoint rather than any normal update, reputation, or time-sync process.
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 workstation is receiving a legitimate software update from the vendor.
Why it's wrong here
Vendor updates typically resolve to consistent, recognizable domains and occur on a scheduled or triggered basis, not every few minutes with random names. Updates also transfer larger payloads over HTTPS, not tiny amounts to changing external addresses. The pattern described does not match normal update behavior and would not explain the randomized DNS lookups.
- ✗
The workstation is synchronizing its clock with an external NTP server.
Why it's wrong here
NTP synchronization uses UDP port 123 and contacts configured, stable time servers, producing a predictable pattern without DNS queries for random domains. The volume and destination pattern described, with frequent unique names and small data transfers, is inconsistent with time synchronization. Clock sync also would not generate the observed external IP traffic.
- ✓
The workstation is infected with malware that uses DNS tunneling for command and control.
Why this is correct
Random-looking domains queried at regular short intervals, combined with small outbound transfers, match DNS tunneling used by malware to reach a command-and-control server. Because DNS is normally allowed through firewalls, attackers encode data in queries and responses. The absence of a logged-in user and the automated cadence point to a compromised host rather than legitimate activity.
- ✗
The endpoint protection agent is performing a cloud reputation lookup for each file.
Why it's wrong here
Reputation lookups go to the security vendor's known cloud service over HTTPS and are tied to file activity, not to randomly generated domain names. They also occur when files are scanned, not continuously while no user is logged in. This does not account for the regular small outbound transfers to external IP addresses.
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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 CompTIA exam blueprint
This 220-1202 practice question is part of Courseiva's free CompTIA 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 220-1202 exam.