Basic Security in Wireless Networks
By Gabriel Torres on August 24, 2009
We can finally say that wireless networks are the standard for connecting computers now. Wireless network cards are for long a standard laptop built-in accessory. Almost all broadband routers – a peripheral that allows you to share your broadband Internet connection with several computers – come with an antenna for wireless networking, allowing the sharing of your Internet connection not only with computers connected to the router by cable, but also to those that have antennas for wireless network. With the popularization with wireless networks came also the increased number of users being hacked and their connection or even important data being watched and stolen. In this short tutorial we will teach you the basics of wireless networking security: how to change the default router password, how to upgrade the router firmware, how to enable encryption and making sure that you are using the correct kind of encryption.
Broadband routers can be installed very easily. All you have to do is to plug your broadband connection to the connector called WAN and the computers of your home or office to one of the ports called LAN, do a basic configuration for the type of broadband connection that you have (ADSL or cable) and you’re done, everything will be working. If your router has an antenna, the computers in our home or office that have an antenna for wireless networking will be connect to the Internet and your local network will work perfectly too.
And here is the danger. Since nowadays most broadband routers support wireless networking and it comes enabled by default, you will have a wireless network enabled in your office or home even if you are not going to use it! Also, most users get so excited that their wireless connection worked seamlessly that they forget about a very important detail. Each and every computer with antenna for wireless network installed in the area will have access to their network. That includes your neighbor's computers and those of hackers stalking the data of your network, or at least enjoying the possibility of surfing the web for free (for you are the one who pays the bill). Reports of hackers who walk the streets of the great urban centers carrying their notebooks hunting for wireless networks without any kind of protection are more and more common.
To solve this problem, you need to disabled the wireless networking capability from your router if you are not going to use it or enable encryption, if you are. This configuration must be done both in your wireless router and in the computers that have wireless networking cards that you want to have access to your network and/or your broadband internet connection.
There are several encryption algorithms and methods available, the most commons called WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access) and WPA-2. The problem is that both WEP and WPA methods proved to be flawed, meaning that if your wireless network is currently configured under any of these modes, it is vulnerable. Worse than knowing that your network is unprotected is thinking that it is protected while it isn't!
Another problem is that several users forget to change the default password for the control panel for their routers, which is practically the same as leaving the router without any password at all: when a hacker sees a login screen from a router the first thing he will try is the manufacturer’s default password (e.g., “admin” or “administrator”). So you need to change this as well.
In summary, after installing your broadband router, you need to:
The first thing you need to do is to access the control panel of your router. That is done via browser, using a special address (such as http://192.168.0.1, http://192.168.1.1 or http://192.168.0.254 - the exact address depends on the model and has to be checked in the manual). At first you will need to enter the default user and password, which is the one that comes written on the quick start guide or user manual (e.g., “admin”/“admin” or “administrator”/“administrator”).
After you enter the control panel from the router, look for an option called “password,” “change password” or similar. The exact name and location will vary according to the router manufacturer and model, and it is almost impossible for us to list all possible locations. We were using a router from Linksys and on this particular product this option was under “Administration.” As you can see in Figure 1, all we needed to do was to enter the new password under “Router Password,” repeat it again under “Re-enter to confirm” and then click “Save Settings.” Some routers, like the one we were using, do not allow you to change the user name, only the password.
After saving the changes, a new login using the new password will be necessary.
Some routers come with the remote management option enabled by default. This option allows anyone to access the router control panel from the Internet. For example, let's assume that the public IP address your Internet provider gave you is 188.8.131.52. If remote management is turned on, anyone on the Internet pointing his/her browser to your IP address (e.g., http://184.108.40.206) will have access to your router control panel (you will have a password enabled so the hacker will actually see the login screen). Of course this the most potential entry point to your network and that is why you should disable remote management, unless you are 100% sure you need this option (some technicians will leave this option turned on so they can manage their clients' network remotely - they will need to know their public IP address, of course).
A very powerful trick in using remote management is changing the connection port. For example, if you change the connection port to 8081, people trying to open your IP address without entering this port number on their request (e.g., http://220.127.116.11) won't be able to access to the control panel. To access the control panel remotely, you will need to enter a colon and the port number (e.g., http://18.104.22.168:8081), creating a difficulty layer to the remote access.
The exact location where you configure remote management depends on your router model and brand. On the router we were using, this option was available under the "Administration" option, on the same screen where we change the administrative password. See the option "Remote Management" in Figure 1 presented in the previous page, where we disabled this option.
Firmware is the software the runs inside any hardware device. In the case of your broadband router, you need to keep this software up-to-date to make sure your network is protected against any known flaws and, more importantly, vulnerabilities.
Login to the control panel from your router as described in the previous page and look for a place where it shows the current firmware version. In the case of our router, this was shown on the upper right corner from every page.
A few routers allow you to download and upgrade the latest firmware by just clicking a button inside their control panel. If you are the lucky owner of one of these routers, look for an option that downloads and upgrades the firmware automatically. In most cases, however, you will need to download a file to your computer, upload this file to your router and then proceed with the firmware upgrade.
To download the latest firmware, go to your router manufacturer website and look up on the download section or support pages if there is a more recent firmware for your router. You will need to know the exact model number from your router and sometimes also the revision (tip: look at the sticker available on the product). You can see here a complete list of manufacturers and their respective websites.
After locating the file, see if it carries a version number higher than the one your router is currently using. Of course if your router is already using the latest firmware available no upgrade is necessary. Then download the file to your computer. Usually the file will have a zip extension, meaning that you need to uncompress it before uploading to the router.
Next locate on the control panel from your router where you can upgrade its firmware. As usual the exact location will depend on you router manufacturer and model. In our case this option was called “Firmware upgrade” and was available under “Administration.”
On this screen, shown in Figure 2, you will need to browse your computer for the uncompressed firmware file (that usually has the extension bin) and then click on the “Upgrade” box.
The upgrade process takes a little while and after the upgrade a new login will be necessary.
If you are not going to use the wireless capability from your broadband router, you must disable it, otherwise hackers will be able to easily access your network using a computer with a wireless network card.
The exact name and location of this option will vary according to your router manufacturer and model. In our case this option was available under “Wireless,” “Basic Wireless Settings,” “Wireless Network Mode.” In theory this option configures the wireless network mode (i.e., speed), but it also presents an option called “Disabled,” as you can see in Figure 3. After selecting this option, simply click on “Save Settings.” Of course if you want to have a wireless network you need to keep this option configured with the wireless mode (speed) you want to use.
Now you need to enable WPA-2 encryption. As we explained, routers come with no encryption at all, meaning that anyone can have access to your network! As usual, the exact location where this configuration is done will depend on your router brand and model. In our router this configuration was available under “Wireless,” “Wireless Security.” Several encryption options are available, as you can see in Figure 4. Choose WPA-2 or “WPA2 Personal” (the “WPA2 Enterprise” option allows the use of a RADIUS authentication server for users to login to the network; this feature is normally only used on large corporate networks). If your router doesn’t list WPA2 as an option, this means your router doesn’t support WPA2 (probably because it is an older model). We’d suggest you to upgrade its firmware, but this should be already done by now. In this case we strongly suggest you to replace your router, as your network won’t be secure with it.
After choosing WPA-2 as the encryption mechanism to be used, you will need to create a security key (think of it as a password to access your wireless network). Users willing to connect to your network wirelessly will need to configure this key on their computers. You need to create a random key containing 63 alphanumeric characters. It can be shorter, but we don’t recommend. Just go crazy pressing random characters on your keyboard, don’t feel tempted in actually typing something that make sense (see example in Figure 5; obviously don’t use the example we are giving). After typing this random 63-character word, select it, copy it to Notepad and then print it. Don’t forget to save it by clicking on “Save Settings.”
The last step is obviously configuring the computers you want to have access to your network wirelessly to use the encryption key you configured, otherwise they will be blocked out of your network.
For that, simply click on the wireless network icon on the task bar (one of the small icons near the computer clock) and select your network from the list that will be shown (see Figure 6). To make sure the correct kind of encryption is enabled, double check to see if “WPA2” is listed for your network. In our case, our network was called “Gabriel,” see how WPA2 is being listed for this network.
By the way. Change the default network name (SSID) if you haven’t done so. If you use the router’s default name (e.g., “linksys”) you may end up having several networks with the same name on the same area, making it confusing to identify which network is yours from the list of detected networks.
After selecting your network and clicking on “Connect,” the operating system will ask you to enter the network key (that random 63-character word) two times. You only have to do this on the first time the computer connects to your network, after that the computer memorizes the key.
That’s it, now you are safe to use your network and can sleep better at night!