Wireless Security: IEEE 802.11i, Threats, Handshakes & WPA3

Why Wireless Security Matters

Wireless networks (Wi-Fi, Bluetooth, NFC) are everywhere—from Pathao’s driver-to-app communication to Ncell’s 4G towers—but they face unique threats:

• Eavesdropping: Capturing unencrypted data (e.g., Khalti transactions over public Wi-Fi).
• Rogue APs: Fake hotspots (e.g., "Free_Nepal_WiFi" in Kathmandu) to steal credentials.
• DoS Attacks: Jamming signals (e.g., NTC’s 4G outages during protests).

IEEE 802.11i (WPA2/WPA3) was designed to fix these flaws in WEP (weak encryption) and WPA (vulnerable handshakes).

1. Wireless Threats: Real Attacks in Nepal

mindmap
  root((Wireless Threats))
    Passive Attacks
      Eavesdropping["Data sniffing (Wireshark, Airodump-ng)"]
      Traffic Analysis["Timing/pattern analysis (e.g., Daraz order queues)"]
    Active Attacks
      Rogue AP["Fake hotspot (e.g., 'Nepal_Gov_WiFi')"]
      Man-in-the-Middle["ARP spoofing (MITM) on Khalti payments"]
      DoS["Deauthentication floods (disconnects Ncell users)"]
    Cryptographic Attacks
      WEP Cracking["RC4 weak keys (e.g., old café Wi-Fi)"]
      WPA2-PSK Brute Force["Offline dictionary attacks on WPA2" ]

Example: In 2022, a Karmasploit attack tricked users into connecting to a rogue AP at Thamel’s Starbucks, capturing login credentials for eSewa and Khalti.

A typical home router (like those in Pokhara cafés) vulnerable to rogue AP attacks. (Image: Khruner, CC BY-SA 4.0, via Wikimedia Commons)

2. IEEE 802.11i: Fixing WEP/WPA Flaws

Key Improvements Over WEP/WPA

Why AES-CCMP?

• AES-128 encrypts data in 128-bit blocks (unlike WEP’s 64-bit RC4).
• Counter Mode (CTR) ensures each packet gets a unique key.

How WPA3’s SAE (Simultaneous Authentication) Works

sequenceDiagram
    participant Client as Mobile Device (e.g., Pathao Driver App)
    participant AP as Access Point (e.g., Ncell Hotspot)
    Client->>AP: Connect (EAP-SAE start)
    AP->>Client: Diffie-Hellman (DH) public key
    Client->>AP: DH public key + Commitment
    AP->>Client: Verifier (proof of key)
    Client->>AP: Final key (PTK derived)
    Note over Client,AP: No password sent in plaintext!

Real Example: When a Pathao driver connects to Ncell’s Wi-Fi, SAE ensures their app credentials aren’t stolen via MITM.

3. Four-Way Handshake: Step-by-Step

stateDiagram-v2
    [*] --> Auth: Start
    state Auth {
        [*] --> Pairwise: EAPOL-Start (Client)
        Pairwise --> Auth1: EAPOL (AP sends ANonce)
        Auth1 --> Auth2: EAPOL (Client sends SNonce + MIC)
        Auth2 --> Auth3: EAPOL (AP sends GTK + MIC)
        Auth3 --> [*]: PTK/GTK installed
    }

Worked Example: Khalti’s Wi-Fi Payment

1. Your phone (Client) sends EAPOL-Start to the café’s AP.
2. AP replies with ANonce (random number).
3. Your phone sends SNonce (its random number) + MIC (message integrity code).
4. AP verifies MIC, sends GTK (group key for all devices) + its MIC.
5. Both sides derive PTK (pairwise key) for secure data transfer.

Failure Case: If the MIC fails (e.g., MITM attack), the handshake aborts.

4. WPA2 vs. WPA3: What’s New?

Real Example: Google Wi-Fi uses WPA3-SAE to prevent Krack attacks (which exploit WPA2’s handshake flaws).

5. Wireless Security in Nepal: Case Studies

A. Ncell’s 4G Security

• Uses WPA2-Enterprise with 802.1X for towers.
• Problem: Rogue APs in Lalitpur mimic Ncell SSIDs to steal data.
• Fix: DNSSEC (Unit 8) + MAC filtering (though MAC spoofing bypasses this).

B. Pathao’s Driver-App Traffic

• Threat: MITM attacks on driver-to-app Wi-Fi (e.g., fake "Pathao_Hotspot").
• Solution:
  1. WPA3-SAE for driver login.
  2. TLS 1.3 (Unit 4) for payment data.
  3. Device PIN (Unit 3: IDS detects unusual logins).

C. Kathmandu Traffic Cameras (IoT)

• Threat: Hackers jam NTC’s traffic camera Wi-Fi to alter signals.
• Solution: WPA3 + AES-256 + physical tamper detection.

6. Common Attacks & Defenses

Worked Example: Stopping a Krack Attack on eSewa

1. Attacker sends forged Group Key during handshake.
2. WPA3-SAE detects the mismatch and drops the connection.
3. IDS (Unit 3) logs the failed handshake as a potential attack.

7. Exam Tip: How to Score Full Marks

1. Diagrams Are Mandatory:

   • Draw the four-way handshake (sequence diagram) or state machine.
   • Label PTK, GTK, ANonce, SNonce, MIC in your answer.

2. Compare WPA2 vs. WPA3:

   • Mention SAE, forward secrecy, and resistance to offline attacks.
   • Example: "WPA3’s Dragonfly Key Exchange prevents brute-force attacks seen in WPA2-PSK."

3. Real-World Tie-Ins:

   • Link Pathao’s driver app to mutual authentication.
   • Link Ncell’s 4G to WPA2-Enterprise + 802.1X.

4. Common Pitfalls:

   • ❌ Don’t say WEP is "secure" (it’s broken).
   • ❌ Don’t confuse TKIP (WPA) with CCMP (WPA2/WPA3).
   • ❌ Always mention MIC verification in handshakes.

5. Short-Answer Secrets:

   • Four-way handshake: 4 EAPOL messages → PTK/GTK installation.
   • WPA3 advantage: "No password in plaintext" (SAE).
   • Threats: Rogue AP, Krack, Evil Twin.

Final Visual Summary

flowchart TD
    A["Wireless Threats"] --> B["Eavesdropping<br/>Rogue AP<br/>DoS"]
    B --> C["WEP/WPA Flaws"]
    C --> D["802.11i Fixes<br/>AES-CCMP<br/>Four-Way Handshake"]
    D --> E["WPA2: Enterprise<br/>WPA3: SAE + Forward Secrecy"]
    E --> F["Nepal Use Cases<br/>Ncell 4G<br/>Pathao App<br/>NTC IoT"]