Module 2: Wireless Networks

Overview

• Infrastructure is the term used to describe the organization and relationships between access points (APs) and clients.

• Wireless Distribution System is a way to connect multiple APs without Ethernet cables between them in order to create a single network.

• Ad-Hoc Networks are a type of network in which all devices are equal.

• Mesh Networks are a type of network where all APs are equal, and don't have defined roles.

• Wi-Fi Direct is also known as Wi-Fi Peer-to-Peer (P2P).

• Monitor Mode is not an architecture, per se, but a mode used by wireless cards that will help us capture Wi-Fi frames and inject packets during a penetration test.

Infrastructure

DS, BSS, and ESS relationships

On Linux-type operating systems, acting as a station is usually called Managed mode and acting as an AP is usually called Master mode.

Wireless Distribution Systems

WDS has two connectivity modes:

• Wireless Bridging: Only allows WDS APs to communicate with each other.

• Wireless Repeating: Allows both stations and APs to communicate with each other.

Wireless Distribution System (WDS) diagram

Ad-Hoc Networks

Ad-Hoc network diagram

Neither WDS nor Ad-Hoc (with a routing protocol) are ideal due to both the complexity of the setup and bugs in the implementations of the standard by the various vendors. The more repeaters that are added, the greater the complexity in setting up, as well as in managing and routing packets efficiently. In Ad-Hoc,1 bugs lead to random disconnection of certain nodes on the network. WDS is often limited to WEP or unencrypted networks, and WPA2 is tricky to get working.

Ad-Hoc Demo

This is a deviation from a standard Ad-Hoc or IBSS mode. It is also referred to as Pseudo-IBSS because it's a pre-standard, pre-IBSS mode with just data. There are no management frames (at all), and the BSSID is all zeros.

Mesh Networks

There are two peering modes available:

• Mesh Peering Management (MPM): Unsecure peering. (Rogue stations may hijack connections)

• Authenticated Mesh Peering Exchange (AMPE): Secure peering.

Mesh network diagram

• Mesh Point (MP): Devices that establish a link between mesh devices. These can be either Mesh Portals, Mesh APs, or even other Mesh Points.

• Mesh AP (MAP): Devices that have the functionality of a Mesh Point and an Access Point.

• Mesh Portal (MPP): Devices that provide a link between the wired network and the wireless network.

Wi-Fi Direct

Wi-Fi Direct is also called Wi-Fi P2P. It is not an 802.11 standard or an amendment, but a technical specification from the Wi-Fi alliance. Devices offering a service act as a software access point with WPS-style connections using WPA2 encryption. It must also allow service discovery.

Monitor Mode

Monitor mode is essential for wireless penetration testing as it enables the capture of raw 802.11 frames and allows packet injection.1 The majority of the tools used to test Wi-Fi networks require our wireless interface to be in monitor mode.