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44. Mobile Device Security – Android, iPhone, Bluetooth and Wi-Fi

44.8 Wi-Fi on Phones – Evil Twin and Captive Portal Awareness

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Quick answer: the short, self-contained version of this lesson is the guide Android Public Wi‑Fi and Hotspot Risks.

Evil twin = attacker AP uses a familiar SSID (e.g. Sahyadri-Guest) to lure phones. Captive portal = "click Accept to get internet" page – sometimes real (hotel), sometimes a phishing skin asking for Microsoft / Google passwords.

Blue habits on phones:

  1. Prefer known office SSIDs; ask IT for the real name
  2. On untrusted Wi-Fi: prefer HTTPS sites / apps; consider company VPN
  3. Do not type passwords into odd captive pages that ask for Google / bank login
  4. Forget café networks after use; turn off auto-join for random SSIDs
  5. Lab evil-twin demos = OWN lab AP / host-only only – never café customers
Red team (attacker) does Blue team (defender) detects / stops
Spins twin SSID near office Staff training; EAP-TLS / known portals; VPN
Captive page steals Google password Password managers that check domain; reject lookalikes
Downgrades / strips TLS where possible (awareness) HTTPS / HSTS habits; VPN on untrusted nets

Ravindra Bagale's Tip

Students open the corporate ERP on airport Wi-Fi without a VPN. Interview: "Untrusted Wi-Fi → VPN + HTTPS; I never practise evil twin against the public." Keep this in mind.

Lab

Design-only: draw Raja phone joining fake Sahyadri-Guest. Mark where VPN would protect app traffic. Optional OWN lab: host a captive test page on 192.168.56.50 HTTP for your emulator only – never bridged to real users.

Extended teaching notes

Why this lesson matters

Cameras, sensors and plant controllers often ship with weak defaults. Segment them from IT, change passwords, block inbound internet, and watch outbound traffic.

Real examples

Global: Mirai showed what default passwords on routers/cameras can do at scale. Indian SME (sample): a factory puts PLCs on a separate VLAN reachable only via a jump host.

Mini case study

Suppose we are on a purple-team exercise for an Indian mid-size company (sample data). Red notes a technique from this lesson against a lab clone. Blue must show the control that stops it, the log that would have fired, and the ticket that hardens production. That is the standard this course trains you for.

Defender's worksheet (do this today)

  1. Write the lesson title, date and the exact lab target you are allowed to use.
  2. List three owned systems (VMs, apps, or cloud accounts) where this lesson applies.
  3. Run one safe check from the lesson on a lab system only. Paste the command and output.
  4. Write a two-sentence fix you would give a teammate.
  5. Name one related public advisory (CERT-In, CISA, NVD, or a vendor bulletin) with its date.

Indian workplace (sample data)

Suppose we are a junior analyst at Infosys, TCS, Wipro or a fintech SOC in Bengaluru/Pune. Turn this lesson into one checklist item with an owner, a due date and a place to store evidence (ticket + screenshot).

Global practice

Compare your notes with OWASP, CIS Benchmarks, NIST CSF/IR guidance or a cloud Well-Architected security question. Write five lines on what overlaps.

Everyday analogy

Explain the risk and the fix to a family member without jargon. If they can repeat the warning, you understand it well enough to teach juniors.

Key terms

  • Control: a safeguard (patch, config, process, detection).
  • Finding: a weakness backed by evidence.
  • Remediation: the fix plus how you verified it.
  • Scope: systems you have written permission to touch.
  • Least privilege: only the access the task needs.
  • Defence in depth: several layers so one failure does not end the story.

Common mistakes

  • Skipping written permission "just for a quick scan".
  • Practising on hostel, office or public targets without authorisation.
  • Collecting tool output without writing the fix.
  • Copying attack steps onto production to "verify". Defenders verify with versions, configs and patches.
  • Publishing screenshots that contain secrets, cookies or internal hostnames.

Recap

  • Evidence, fix, owner, date.
  • Own lab only.
  • Fix > spectacle.