Project 68: DNS Tunneling Detection

Module: Module 7: Wireless, Systems & Mobile Security  |  Level: Intermediate  | 
Primary tool: Wireshark + a sample tunneling pcap  |  Estimated time: 75–120 minutes

Objective: Recognize the traffic pattern of DNS used as a covert data channel.

Free lab environment

LetsDefend (free tier) + CyberDefenders (free challenges) — https://letsdefend.io/ and https://cyberdefenders.org/blueteam-ctf-challenges/

Both platforms offer free-tier SOC-analyst simulations with real (sanitized) logs, alerts, and packet captures, so you can practice detection and triage without needing your own production environment.

Lab workflow

1. Access the free lab scenario (Wireshark Sample Captures wiki (or a self-generated iodine/dnscat2 test in an isolated lab)) and read the provided context before looking at any alert.
2. Using Wireshark + a sample tunneling pcap, review the available logs/alerts with the specific goal of learning to recognize the traffic pattern of DNS used as a covert data channel.
3. For each candidate indicator, write down why it is suspicious in plain English before deciding it’s a true positive — this discipline avoids alert-fatigue-driven guessing.
4. Draft the detection rule or logic (in plain English or pseudocode) that would have caught this automatically in the future.
5. Cross-check your conclusion against the platform’s model answer or scoring, if provided, and note any gap between your reasoning and the expected answer.
6. Write up your finding as a short incident note: what happened, how you knew, what you’d do next.

Evidence & screenshot requirements

Submit the following with your report (see this module’s practical assignment for exact upload details):

• a Wireshark filter isolating unusually long/high-entropy DNS queries
• your written detection rule idea for flagging this pattern automatically

Expected deliverable

A concise lab-report entry containing: scope/target, exact commands or payloads used, your key
observation, the required screenshots above, and — where applicable — the specific remediation for what
you found. Vague answers (“sanitize input”, “use a firewall”) without naming the exact mechanism will not
receive full credit.

Safety & authorization

Only test the specific free lab target named above, or infrastructure you personally own. Do not target
third-party systems, real user accounts, or production services without explicit written authorization.
Never deploy anything from this project outside an isolated lab environment.