Steganography & Covert Channel Detection
Intermediate75 min5 objectives

Steganography & Covert Channel Detection

Complete Steganography & Covert Channel Detection in a deterministic practice workspace without depending on unavailable host, cloud, hardware, desktop, or multi-node infrastructure.

Briefing

### Scenario You are a general practitioner handling a realistic client engagement. For Steganography & Covert Channel Detection, the client has provided a staging environment that mirrors production but is isolated to this lab. Your task is to demonstrate the core technique on the local target without touching external systems. The scenario is intentionally scoped to what you can verify inside the container. ### Environment and scope Use the Ubuntu 22.04 practice container. Working directory is `/home/student/lab-work` (create it with `mkdir -p`). Target is `127.0.0.1` and `127.0.0.1:8080` where a `python3 -m http.server` or service-specific daemon runs. Install only needed tools via `sudo apt-get update && sudo apt-get install -y curl, python3, nmap, openssl` then verify with `curl --version && python3 --version`. Credentials: `student:lab123` with `sudo` (created via `useradd` + `chpasswd` + `sudoers.d` as in `labs.service.ts:554`). Do not scan or query outside 127.0.0.0/8 or lab-work. Scope is strictly container-only; no external cloud, hardware, or nested container engines. ### Mission objective For Steganography & Covert Channel Detection: install and verify tooling, prepare the local target (`127.0.0.1 and /home/student/lab-work`), execute the technique step-by-step, and collect evidence. Each walkthrough step produces a verifiable artifact (file, command output, or service state) that you will cite in your submission. ### Success criteria You have completed the lab when: - Tooling verification passes (`curl --version && python3 --version` returns expected version without error) - Local target is running and responds (`curl -s http://127.0.0.1:8080/` or `dig @127.0.0.1` or `tshark -r` shows expected output) - `solution.md` in `lab-work` documents each step's exact command, raw output excerpt, and your interpretation (what the output proves) - All flag answers are direct values from your local output (e.g., version string, status code, IP, header name) and no external hosts were targeted (`history | grep -E "nmap|dig|tshark|openssl|nikto|curl"` shows only 127.0.0.1) Runtime mode: portable artifact validation

Objectives

  • 1Prepare workspace and verify tooling
  • 2Prepare local target for Steganography & Covert Channel Detection
  • 3Execute Steganography & Covert Channel Detection technique
  • 4Capture evidence
  • 5Complete LSB Detector
  • 6Complete JPEG Analyzer
  • 7Tune and interpret
  • 8Compile and verify submission

Flags

LSB Detector+200 pts

Submit the verifiable output value for LSB Detector as produced by the local tool on 127.0.0.1 (e.g., version, status, IP, or header).

JPEG Analyzer+200 pts

Submit the observed value for JPEG Analyzer from local tool output on 127.0.0.1 (e.g., status code, header name, or count).

DNS Tunnel Detector+200 pts

Submit the verifiable output value for DNS Tunnel Detector as produced by the local tool on 127.0.0.1 (e.g., version, status, IP, or header).

Steg Detector+150 pts

Submit the verifiable output value for Steg Detector as produced by the local tool on 127.0.0.1 (e.g., version, status, IP, or header).

Steghide Extractor+150 pts

Submit the verifiable output value for Steghide Extractor as produced by the local tool on 127.0.0.1 (e.g., version, status, IP, or header).

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