Narrowband Technology

In radio, narrowband describes a channel in which the bandwidth of the message does not significantly exceed the channel's coherence bandwidth.
In the study of wired channels, narrow band implies that the channel over consideration is sufficiently narrow that its frequency response can be considered flat. The message bandwidth will therefore be less than the coherence bandwidth of the channel. That is, no channel has perfectly , but the analysis of many aspects of wireless systems is greatly simplified if flat fading can be assumed.
Narrow band can also be used with the audio spectrum to describe sounds which occupy a narrow range of frequencies.

Countermeasures for Wireless Attacks

Wireless Attacks and Countermeasures

Wireless communication poses formidable challenges for the security professional. Many wireless manufacturers design their devices for easy set up and use, often at the expense of sound security practices. Many wireless devices default to little or no security. A security professional must take extra precautions to protect sensitive data transmitted over wireless devices. Two protocols that have been implemented to provide security for wireless communication are: Wired Equivalent Privacy (WEP) implements the 802.11 specification for wireless network connections. Wireless Application Protocol (WAP) is used with mobile devices such as PDA's and smart phones. The following table describes weaknesses with both WEP and WAP: Protocol Vulnerabilities Wired Equivalent Privacy (WEP) WEP suffers from the following weaknesses: The key is vulnerable during authentication. The same WEP key is used for authentication and data encryption. The WEP key is static. Because it doesn't change, it can be captured and broken. Every host on the network uses the same key. Key rotation is difficult. WEP uses a very short initialization vector (IV) - a mechanism that allows a cipher to be executed in any of several streaming modes of operation to produce a unique cipher text using the same encryption key. The integrity check value (ICV) is easily defeated. Unless you specify data encryption, all frames are sent in plaintext. The RC4 encryption cipher could be replaced by a stronger encryption cipher. The Service Set Identifier is broadcast. Authentication can be open, meaning that identity is not checked. Most wireless stations can be configured using the network name ANY. Wireless Application Protocol (WAP) The most significant weakness of WAP is referred to Gap in the WAP, a security gap between a WAP client (handset) and a LAN host. The Gap in the WAP attack: Exploits the decryption of transmissions at a carrier midpoint. Compromises the carrier before the data is re-encrypted. Exposes plaintext data. WAP deploys Wireless Transport Layer Security Protocol (WTLS) for authentication: Class 1, Anonymous Authentication Class 2, Server Authentication Class 3, Two-Way Client and Server Authentication Wireless networks are vulnerable to the following specific security attacks: Vulnerability Description Eavesdropping Eavesdropping is the most common threat of a wireless network. Wireless transmissions can be easily intercepted. Site surveys or war driving Site surveys or war driving are attempts by a hacker to scan the wireless networking area looking for unsecured access points or weak passwords. Rogue access points or Man-in-the-middle Rogue access points or man-in-the-middle attacks occur when an attacker installs an unauthorized access point into your wireless network, allowing them to connect to the network. Replay attack In a replay attack, an attacker intercepts and records messages. The captured traffic is used at another time to try and recreate authentication. WEP, with its short initialization vector and static keys is susceptible to replay attacks. Countermeasures for wireless communications are: First and foremost, treat a wireless network as though it were a publicly accessible network. Don't assume that the traffic on that network is private and secure. Put the access points in separate virtual LANs and implement some type of intrusion detection to help identify when an attacker is attempting to set up a rogue access point or is using a brute force attack to gain access. Encrypt all data transmitted through your access point. Set the access point to accept only Media Access Control (MAC) addresses. Use firewalls on each network access point. Avoid storing sensitive data on wireless machines whenever possible. Encrypt sensitive data that must be stored on the machine. Install security updates as soon as they are available. Install antivirus software on the wireless computer. Require that users connect to the wireless access point with a network cable when sending sensitive data. Disable the broadcasting of the SSID from all access points. Implement EAP-TLS to use different keys for encryption and broadcast traffic. Set the WEP broadcast traffic key to be renegotiated at a certain interval. Set up a RADIUS server and a certificate authority. The RADIUS server authenticates the user back against your network directory service.

Kismet Video

How to change your SSID and Disable SSID broadcast

By default, your wireless network transmits a service set identifier (SSID) so devices with a wireless network adapter can see the networks in range of their device and attempt to connect. This is how your smartphone knows you’re at home and in range of your personal network. While this is good for public wireless networks such as those found in libraries, coffee shops and other public locations, it may not be best for your home personal network. An easy way to prevent unwanted connections to your wireless network is to change your assigned SSID and prevent your router from broadcasting it to just anyone. Here’s how you can make that setup work for you.

1. Log into your account. Open your browser and enter the manufacturer’s default IP address, typically located on the underside of your router or in the user manual or a custom one that you set. Using your username and password, log into your router settings page.

2. Open the Wireless tab to edit your wireless settings. Once there, go to the “Primary Network” (or equivalent) tab if you’re not already on the correct page.

3. Click to change your SSID to something personal. In the SSID field, you’ll want to change the SSID from the generic assigned identifier to something more personal and easy to remember (for example, Domanico’s WiFi). Think of a name that will be difficult for an outsider to guess, but not something so tough you’ll struggle to remember it. Write it down and keep the name of your network in a safe place.

4. Disable SSID broadcast so that only people you’ve given your SSID to can access the network. The label of the setting by which to accomplish this will vary with your router, so be sure to consult with your manual. For our router, enabling the Closed Network setting does the trick.

5. Manually enter your new SSID to connect devices to your network. To do so on your Windows laptop, open the Control Panel > Network and Sharing Center. Click “Set up a new connection or network.” Then click “Manually connect to a wireless network,” and enter your SSID and password.

What is a netstumbler?

Q:What is Netstumbler?
-NetStumbler is a tool for Windows that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g. It has many uses:
-Verify that your network is set up the way you intended.
-Find locations with poor coverage in your WLAN.
-Detect other networks that may be causing interference on your network.
-Detect unauthorized "rogue" access points in your workplace.
-Help aim directional antennas for long-haul WLAN links.
-Use it recreationally for WarDriving.

Kismet

Kismet is an 802.11 layer2 wireless network detector, sniffer, and intrusion detection system. Kismet will work with any wireless card which supports raw monitoring (rfmon) mode, and (with appropriate hardware) can sniff 802.11b, 802.11a, 802.11g, and 802.11n traffic. Kismet also supports plugins which allow sniffing other media such as DECT.

Kismet differs from other wireless network detectors in working passively. Namely, without sending any loggable packets, it is able to detect the presence of both wireless access points and wireless clients, and to associate them with each other. It is also the most widely used and up to date open source wireless monitoring tool.

 Kismet also includes basic wireless IDS features such as detecting active wireless sniffing programs including NetStumbler, as well as a number of wireless network attacks.
Kismet features the ability to log all sniffed packets and save them in a tcpdump/Wireshark or Airsnort compatible file format. Kismet can also capture "Per-Packet Information" headers.

Kismet also features the ability to detect default or "not configured" networks, probe requests, and determine what level of wireless encryption is used on a given access point. In order to find as many networks as possible, Kismet supports channel hopping. This means that it constantly changes from channel to channel non-sequentially, in a user-defined sequence with a default value that leaves big holes between channels (for example, 1-6-11-2-7-12-3-8-13-4-9-14-5-10).

The advantage with this method is that it will capture more packets because adjacent channels overlap.Kismet also supports logging of the geographical coordinates of the network if the input from a GPS receiver is additionally available.

The of different wireless technologies that WLANs use

An Overview of Wireless Technologies

Now that you understand the different frequencies on which radio waves can travel, take a look at the three technologies WLANs use:●  Infrared—Infrared light can’t be seen by the human eye. Infrared (IR) technology is restricted to a single room or line of sight because IR light can’t penetrate walls, ceilings, or floors. This technology is used for most remote controls and for syncing PDAs.

●  Narrowband—Narrowband technology uses microwave radio band frequencies to transmit data. The most common uses of this technology are cordless phones and garage door openers.

●  Spread spectrum—For data to be moved over radio waves, it must be modulated on the carrier signal or channel. Modulation defines how data is placed on a carrier sig- nal. For example, spread spectrum modulation means data is spread across a large- frequency bandwidth instead of traveling across just one frequency band. In other words, a group of radio frequencies is selected, and the data is “spread” across this group. Spread spectrum, the most widely used WLAN technology, uses the following methods:

●  Frequency-hopping spread spectrum (FHSS): Data hops to other frequencies to avoid interference that might occur over a frequency band. This hopping from one frequency to another occurs at split-second intervals and makes it difficult for an intruder or attacker to jam the communication channel.

●  Direct sequence spread spectrum (DSSS): DSSS differs from FHSS, in that it spreads data packets simultaneously over multiple frequencies instead of hopping to other frequencies. Sub-bits are added to a packet as it travels across the frequency band and are used for recovery, in much the same way RAID-5 uses parity bits to rebuild a hard disk that crashes. Sub-bits are called “chips,” and every bit of the original message is represented by multiple bits, called the chipping code.

●  Orthogonal frequency division multiplexing (OFDM): The bandwidth is divided into a series of frequencies called tones, which allows a higher throughput (data transfer rate) than FHSS and DSSS do.