Wired Network

The AMPS was designed for voice transmission is a technology that is used to allow data over the same voice channels with a frequency of 800 MHz. The cellular data transfer needs a connection between every end just like a voice session. During this connection the cellular data transmission sends data over the airlink (through a PSTN (Public Switched Telephone Network)) to the remote computer. For a well cellular phone have been utilize radio signals originally radio performance losses signals because of interference of noise and channel degradation which affect data transmission. Therefore ETC (Enhanced Throughtput Cellular) have been introduced to control data compression, error correction and modulation to provide faster reliable transmission along with MNP(Mircrocom Network Protocol)..

WLANs have additional security threats to consider that are RF in nature. Protocol-level attacks that attempt to penetrate Wi-Fi data security include rogue access points, authentication attacks, evil twin access point, man-in-the-middle, Wi-Fi phishing, and malicious eavesdropping. Most of these attacks exit at layer 2 of the OSI model. Proper authentication, encryption, and segmentation security solutions can be implemented to mitigate many of these well-known attacks. Layer 2 security monitoring solutions can also be put in place to detect when layer 2 attacks are taking place. But a major oversight in current wireless intrusion detection systems (WIDS) solutions is that they have been unable to detect layer 1 security threats WIDS typically use 802.11 radio cards that have limited layer 1 visibility......

Packet sniffer's, are protocol analyzers meant to capture the packets that are seen by a machine's network interface. When a sniffer runs on a system, it grabs all the packets that come into and goes out of the Network Interface Card (NIC) of the machine on which the sniffer is installed. This means that, if the NIC is set to the promiscuous mode, then it will receive all the packets sent to the network if that network is connected by a hub. Unfortunately, in a switched network, since switches do not broadcast the packets, sniffers cannot see any packet that is not having the destination address of the machine on which it is installed. This is unfortunate for testing reasons, but fortunate for security reasons. It is fortunate because, if an attacker installs a sniffer in a trusted network, but if the trusted network uses a hub to broadcast the packets within that network, then the sniffer would be able to look at every single packet that is going across the network. Many network monitoring tools are based on passive packet capture. The principle is the following: the tool passively captures packets flowing on the network and analyzes them in order to compute traffic statistics and reports including network protocols being used, communication problems, network security and bandwidth usage. Many network tools that need to perform packet capture ([tcpdump], [ethereal], [snort]) are based on a popular programming library called libpcap [libpcap] that provides a high level interface to packet capture.

The Distributed Coordination Function essentially Carrier a Sense Multiplying Access with Collision Avoidance mechanism (also known as CSMA/CA). CSMA protocols are one of the most known protocols in the industry, where the most common one is Ethernet which refers to CSMA/CD protocol (CD standing for Collision Detection). The CSMA protocol works as A station that transmit senses to the medium if the medium is not responding or some other station is transmitting then the medium will continue transmission at a later stage if the medium is sensed free then the station will accept transmission

A particularly troublesome issue for Wi-Fi security is the denial of service (DoS) attack. In a DoS attack, the goal of the attacker is not to penetrate or steal data from the network it is simply to disable the network. For mission-critical systems, this is a serious security concern. If the WLAN goes down, then any application or network resource being accessed through the WLAN is now no longer available. The wireless VoIP phone conversation comes to an abrupt end, communications with your database server are no longer possible, and wireless access to an Internet gateway has been closed. Many denial of service attacks exist at layer 2 and occur when an attacker manipulates information in the layer 2 header of an 802.11 management frame and then retransmits the edited frames into a wireless environment with some sort of packet generator. Numerous published layer 2 DoS attacks exist. The most common is achieved by manipulating de-authentication or disassociation management frames. Currently, layer 2 DoS attacks cannot easily be prevented, but can be easily detected. The 802.11w Task Group is addressing methods to also prevent many layer 2 DoS attacks. This method has been driven by Cisco's Management Frame Protection under the Unified Wireless vision. In the meantime, wireless intrusion detection systems can detect and locate the radio card that is the source of a layer 2 DoS attack. But denial of service attacks to wireless networks can even more easily occur at layer 1 in the RF environment. Layer 1 DoS attacks are a result of radio frequency interference interference. 802.11 WLAN radio cards use a medium access method called carrier sense multiple access/collision avoidance (CSMA/CA). This medium access method ensures that only one single radio card is transmitting at any given time in the half-duplex radio frequency medium. Part of the CSMA protocol is the clear channel assessment (CCA).