Wireless Network Security

Wireless networking has experienced a huge increase in popularity over the last couple of years. The necessary hardware is widely available to consumers, it is very affordable, and relatively easy to install and configure. Gateway devices, common called "routers" or "firewalls" by consumers, that allow users to share a broadband connection with and protect multiple computers on a home network have been around for a while.

The addition of wireless capabilities to these gateway devices gives the user the convenience of taking a computer anywhere in the house, and not have to worry about running wires through walls and crawl spaces and attics to connect computers in various parts of the house. Industrial-strength high-performance versions have been around even longer in company environments, allowing employees to roam between offices, cubes, and conference rooms with laptops without ever losing connectivity.

It is a great technology that offers many benefits. As the saying goes, however, with privilege comes responsibility. A responsibility that is unfortunately much too often ignored by the person implementing it. A wireless network needs to be properly secured as it poses a number of extremely serious risks and dangers if left wide open and exposed, which many users are unaware of.

Why secure a wireless network?

If you are thinking right now that you have nothing important on your network and that you have no need to secure your wireless network, I guarantee you that you will reconsider your opinion after reading the next few paragraphs. Consider the following dangers of having an unsecured wireless network.

Bandwidth Parasite
In a "best" case scenario, all the intruder does is use the victim's broadband connection to get online without paying. Maybe just to surf the web, maybe to download pirated music or software. This does not cause any direct harm to the compromised network, but it can slow down Internet or network access for the victim, the legitimate user of the network, if an intruder leeches off his bandwidth. This could mean substantial additional ISP cost for the victim if the ISP meters used bandwidth and charges for actual usage.

Masking criminal activity

An unauthorized user could abuse the victim's connection for malicious purposes like hacking, launching a DoS attack, or distributing illegal material. Since the intruder is a part of the private network and sits behind its gateway device, any traffic between him and the Internet will appear to be coming from the public IP address the ISP assigned to the victim. The ISP has no idea how many computers are behind the gateway, who they belong to, and what they are used for. If the criminal activity is discovered and investigated, the origin of the attack will be traced back to the victim's broadband account. It is a pretty safe bet that nobody wants to be accused of and go to jail for distributing child pornography or hacking into restricted company or government networks (just to mention a few examples) if the crime was in reality committed by a cracker from behind an innocent victim's network. Reviewing ISP's Terms of Service usually reveals a clause that not only allows the ISP to reveal customer information to the authorities to assist with legitimate criminal investigations, but also holds the customer responsible for any activities the connection is (ab)used for.

Free access to private data

A wireless network is also a direct backdoor into the victim's private network - literally. Instead of intruding from the public side of the gateway device, the intruder connects directly to the network on the private side of the gateway device, completely bypassing any hardware firewall between the private network and the broadband modem. Most people assume that since they are behind a gateway device with a built-in firewall their private network is safe, hence letting down their guard, sharing drives, and being generally careless. The intruder can completely take advantage of this by snooping around undisturbed and getting access to confidential data. This could be in form of personal information such as financial data, tax records, wills, and more that can be abused for identity theft for example, or in form of work-related information such as confidential specs, development information, trade secrets, and more that the victim has brought home from the office. By employing a sniffer an intruder can even sniff email or FTP user names and passwords because they are usually transmitted in cleartext, and use that information to gain unauthorized access to email accounts or web servers without the victim's knowledge.

Backdoor into corporate networks

In addition, a wireless network could also be an indirect backdoor into a corporate network. An intruder can specifically target an employee of a company whose confidential information is valuable to him for monetary or competitive reasons. If that employee establishes a VPN connection either permanently from his gateway or from a machine behind his gateway to the company network, the intruder can then piggyback on the VPN tunnel and gain unauthorized access to company resources, a serious security breach and every network administrator's nightmare.

That's why
By now the danger should be pretty clear: Unsecured wireless networks are unacceptable due to the extremely high risks involved. Yet there are countless unsecured wireless networks out there. A train ride through the Silicon Valley East Bay area revealed about 60 wireless networks, 40 of them wide open and insecure. A drive around a residential neighborhood covering just a few blocks revealed over 30 wireless networks, 20 of them wide open and insecure.

What is even scarier is that it does not take any skill to discover and gain unauthorized access to wireless networks. One does not have to be a programmer, Linux expert, or network specialist. All it takes is a laptop with a wireless network card, and some software (also available for Windows) that can be easily downloaded for free from the Internet. Armed with these basic tools anybody can drive around, detect open wireless networks, and connect to them. With a Linux machine, additional software, some advanced knowledge, and some time and patience it is even possible to break into wireless networks that use encryption.