Wireless networks - What you should do to secure them and WHY

802.11b or 802.1g... Hiding behind this innocently sounding numbers we find the basis of all Wireless networking. With the ever increasing popularity of wireless networks and globalized networking in general many of us have already made the leap into the wonderful world of wireless.

No more wires! Be online practically anywhere! Those were probably the slogans that roped us into buying our precious access points (wireless connection bridges), WI-FI network cards and all the little tidbits to finally get our networks up and running.

But while we enjoy the connectivity from any and all locations (yes, it does work in the bathroom!) we are also broadcasting practically everything we do on the network to anyone who would care to listen.

All of a sudden we have stepped away from the relative safety of our cables and allowed our neighbors to listen in on our network traffic.

Simply put, wireless networks use radio waves to transmit information from one point to another. Unlike cables where the connection is usually direct (from connector to connector) wireless techniques broadcast their information over larger areas attempting to reach their destination.

Anyone in range of this broadcast is then able to pick up the information you just sent out and is even able to manipulate and influence your transmissions!

Not only does this mean that people will be able to read every single letter of that private email you just sent to (or received from) your wife/husband, but anyone with less than impeccable morals is also able to pick up your passwords to your various internet accounts and use them for their own personal goals.

Those of us that enjoy the benefits of online banking and internet payment methods such as papal will immediately realize that their once secure (cabled) networks are no longer as secure in a wireless environment.

Wait! Before you panic and decide to start ripping access points off the ceilings and re-installing the good old cable network let's take a step back and identify the risks to your wireless network and how we can protect ourselves from them.

We will start by identifying some of the mayor risks to a wireless network without worrying too much about the technical details of each problem, implementing the 'right' protection for each case will be discussed afterwards. Risks to a wireless network (and most other network types) can roughly be placed in the four categories below:

Jamming
Monitoring and Manipulation
Re-configuration
Direct attacks

Jamming

Jamming has long since been the most common form of risk to a wireless network.

A wireless network operates on a specific frequency (e.g. 2.4Ghz) allowing it to communicate with devices that operate on the same frequency. Anyone with equipment like mobile phones, blue tooth devices and other equipment that operates on the same frequency can potentially 'weaken' your wireless network signal by 'flooding' that frequency (much like someone screaming in your ear while you are trying to listen to a radio). Jamming can be intentional but is more often than not the result of accidental or unintentional efforts of the people around you.

(Example: Two apartments with the people using the same model of wireless telephone. If both use the same frequency on their telephone they will hear static or the voices will fade in and out.)

Monitoring and Manipulation

Monitoring and manipulation is by far the most common when it comes to 'hacking' (there's the word we've all been waiting for!) wireless networks. Due to the fact that wireless networks work through broadcasting data anyone with a so called “sniffer” can when standing in range of the broadcast (commonly up to 300 feet depending on the wireless devices) receive and read all data transmitted.

This method is usually used to retrieve the initial login information (username and password) and this information can then be used to hijack the account of the person logging in to the network.

Re-configuration

All wireless devices come with installation manuals. (Even your microwave oven has an installation manual!) Unfortunately, most of us don't read them for whatever reason. This can cause your network to be poorly set up for even the most basic security which in turn allows the “bad guys” greater potential access to your personal information.

Most wireless devices are configured at the factory with the minimum possible security level for when they are sold. This is done so that connecting the access point and the rest of the wireless network is as easy and as painless as possible. (And so that their toll free number is not called by people asking what should be very basic questions!) Even though these devices can be configured to be fairly secure (as far as security goes) any misconfiguration or incorrect re-configuration of the devices can cause the device to not be as secure as you might think.

Direct attacks

Last but not least there is a risk of a direct attack on one or more of the devices (PC's) on your network. Since PC's equipped with wireless network cards can 'talk' directly to other pc's with wireless network cards bypassing the base station or the access point all pc's need to be protected separately.

Flooding a PC with bogus information known as a denial of service attack (causing its' network to grind to a halt), viral threats that can spread from pc to pc and file sharing exploits all fall in the category of direct attacks.

The wireless network also suffers from the fact that devices that were previously not in the network (potentially carrying a virus or otherwise malevolent software) can easily be inserted. Most commonly people will attempt to hook up their laptops or PDAs to the network potentially creating a risk from these unknown devices.

Now that we identified all these threats it's time to see what we can do about them. This will by no means be a complete description of everything you could possibly do. It discusses the most commonly used methods for protection without going into great technical detail and which area of threats they protect against.

First of all Jamming can be largely avoided by minimizing the number of devices operating on the same frequency near your network and limiting your wireless network to only cover smaller areas by using less output power and possibly even directional antennas (which usually results in stronger connections making it harder to drown out your network's signal).

Note: Jamming or interference by other devices generally requires the interfering device to be fairly close to your network making them easier to spot and remove. Reducing jamming attempts by increasing your network's signal strength isn't recommended as it increases the range of your network considerably making it more vulnerable rather than less.

On a wireless network every client (PC, PDA, etc.), every base station and every access point must be considered to be a potential threat. Placing firewalls and forcing authentication requirements between access point and the Intranet or other clients is an excellent way to protect against many forms of monitoring and direct attacks.

All wireless network devices (in fact all networking devices) have a unique identification number known as a MAC address. A lot of access points on the market these days can be set to only allow traffic from specific MAC addresses providing very good protection against many forms of direct attacks.

Similar to singling out MAC addresses access points make use of a so called SSID (Server set ID) that makes it possible to identify a set of devices with the same SSID to communicate. Devices with other SSIDs will simply be ignored. The SSID of all access points have a default value that varies depending on the manufacturer. Changing the default SSID is a critical step to avoiding re-configuration and misconfiguration problems since the default SSIDs for your wireless devices are public knowledge.

And last but not least all wireless networking systems offer a method of protection called WEP (Wired equivalent Privacy) which can be set to encrypt (more or less scramble) the transmitted information at various levels of encryption difficulty (for the happy few who care this can be either 40 or 128 bit encryption). This form of encryption will not protect your data from being read by our unfriendly listener, but will definitely make it harder for the listener to understand what you just transmitted. While WEP isn't perfect it is always better to use WEP than not and all access points and devices on the network should be configured accordingly.

Finally, if security is a very important issue in your network (and it should be!), consider switching to wireless network equipment that provides for security standards such as 802.11x which closely cooperates with various Operating Systems and hardware vendors to provide optimal security for your wireless network.