802.11 Wireless LANs

Up to Date?

This page is no longer maintained, and may contain dated information.

Card

We're using SMC's 11Mbps wireless PC card, SMC2632W. It is built off of the prism II chipset by intersil. As a note, SMC makes a PCI card (SMC2602W) which has their pcmcia card mounted on it. This card is not supported by linux at the moment, to the best of my knowledge.

Linux Software

The card comes with source code for a linux driver. To build, you'll need your kernel sources as well as the sources for the pcmcia subsystem. The main distribution site for this driver is at www.linux-wlan.com. There's a general Wireless LAN HowTo available as well.

The linux-wlan-ng release now includes monitoring support and there is no patching required. Recent versions of libpcap should also support the card.

For monitoring, I use ethereal, you can grab the ethereal here. To enter monitoring mode you'll want to do something like:

    #!/bin/sh
    # Monitor a channel, enter a channel from 1 through 14
  
    DEV=wlan0
    wlanctl-ng $DEV lnxreq_wlansniff channel=$1 enable=true

802.11

Here are some web pages I found useful:

network computing's tutorial
Internsil's technical library which includes chipset specs, application notes as well as some technical overviews of the technologies used.
Intersil's overview of 802.11
Intersil's overview of spread spectrum
Intersil's overview of complementary code keying
A security analysis of WEP from Berkeley
More security problems, from UMD
Overview and Tutorial of IEEE 802.11

Black Hat Talk

Here's an updated version of the slides from my BlackHat talk (also in pdf). They contain several slides that were not in the printed version distributed at blackhat.

wep_tools.tgz contains two utilities for dealing with WEP packet captures. This is still a work in progress. Please do not distribute or mirror these until I finalize the release.