Cyber Security Tip ST05-003 -- Securing Wireless Networks

[US-CERT Security Tips <security-tips () us-cert gov>]

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                         Cyber Security Tip ST05-003
                         Securing Wireless Networks

   Wireless networks are becoming increasingly popular, but they introduce
   additional security risks. If you have a wireless network, make sure to take
   appropriate precautions to protect your information.

How do wireless networks work?

   As the name suggests, wireless networks, sometimes called WiFi, allow you to
   connect to the internet without relying on wires. If your home, office,
   airport, or even local coffee shop has a wireless connection, you can access
   the network from anywhere that is within that wireless area.

   Wireless networks rely on radio waves rather than wires to connect computers
   to the internet. A transmitter, known as a wireless access point or gateway,
   is  wired  into an internet connection. This provides a "hotspot" that
   transmits the connectivity over radio waves. Hotspots have identifying
   information, including an item called an SSID (service set identifier), that
   allow computers to locate them. Computers that have a wireless card and have
   permission  to access the wireless frequency can take advantage of the
   network connection. Some computers may automatically identify open wireless
   networks in a given area, while others may require that you locate and
   manually enter information such as the SSID.

What security threats are associated with wireless networks?

   Because wireless networks do not require a wire between a computer and the
   internet connection, it is possible for attackers who are within range to
   hijack  or  intercept  an  unprotected connection. A practice known as
   wardriving involves individuals equipped with a computer, a wireless card,
   and a GPS device driving through areas in search of wireless networks and
   identifying the specific coordinates of a network location. This information
   is then usually posted online. Some individuals who participate in or take
   advantage of wardriving have malicious intent and could use this information
   to hijack your home wireless network or intercept the connection between
   your computer and a particular hotspot.

What can you do to minimize the risks to your wireless network?

     * Change default passwords - Most network devices, including wireless
       access points, are pre-configured with default administrator passwords
       to simplify setup. These default passwords are easily found online, so
       they don't provide any protection. Changing default passwords makes it
       harder for attackers to take control of the device (see Choosing and
       Protecting Passwords for more information).
     * Restrict access - Only allow authorized users to access your network.
       Each piece of hardware connected to a network has a MAC (media access
       control) address. You can restrict or allow access to your network by
       filtering MAC addresses. Consult your user documentation to get specific
       information  about enabling these features. There are also several
       technologies available that require wireless users to authenticate
       before accessing the network.
     * Encrypt the data on your network - WEP (Wired Equivalent Privacy) and
       WPA  (Wi-Fi Protected Access) both encrypt information on wireless
       devices. However, WEP has a number of security issues that make it less
       effective  than WPA, so you should specifically look for gear that
       supports encryption via WPA. Encrypting the data would prevent anyone
       who might be able to access your network from viewing your data (see
       Understanding Encryption for more information).
     * Protect your SSID - To avoid outsiders easily accessing your network,
       avoid publicizing your SSID. Consult your user documentation to see if
       you can change the default SSID to make it more difficult to guess.
     * Install a firewall - While it is a good security practice to install a
       firewall on your network, you should also install a firewall directly on
       your  wireless  devices (a host-based firewall). Attackers who can
       directly tap into your wireless network may be able to circumvent your
       network firewall—a host-based firewall will add a layer of protection to
       the  data  on  your computer (see Understanding Firewalls for more
       information).
     * Maintain anti-virus software - You can reduce the damage attackers may
       be able to inflict on your network and wireless computer by installing
       anti-virus software and keeping your virus definitions up to date (see
       Understanding Anti-Virus Software for more information). Many of these
       programs also have additional features that may protect against or
       detect spyware and Trojan horses (see Recognizing and Avoiding Spyware
       and Why is Cyber Security a Problem? for more information).
     _________________________________________________________________

     Authors: Mindi McDowell, Allen Householder, Matt Lytle
     _________________________________________________________________

     Produced 2005 by US-CERT, a government organization.

     Note: This tip was previously published and is being
     re-distributed to increase awareness.

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