WiFi technology Writeup


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WiFi technology Writeup

  1. 1. SEMINARS OF SEMISTER – I [ YEAR 2013-2014 ] NAME: SHITAL KATKAR TOPIC: Wifi Technology SIGNATURE:________________ 1
  2. 2. SEMINAR – I WIFI Technology 2
  3. 3. CONTENTS:  Wifi Technology  Radio waves  Flavors Of Wifi  Applications  Advantages  Limitation  Conclusion 3
  4. 4. INTRODUCTION Technology is making rapid progress and is making many things easier.As the innovative thinking of persons is increasing day-by-day,new methods for wireless networking has been evolved of which our present topic Wi-Fi is the most accepted technology. Wi-Fi, an acronym for Wireless-Fidelity which is the wireless way to handle networking. It is also known as 802.11 networking. The big advantage of WiFi is its simplicity. You can connect computers anywhere in your home or office without the need for wires. The computers connect to the network using radio signals, and computers can be up to 100 feet or so apart. RADIO WAVES This is the Electromagnatic spectrum. Range of Radio Wave is 3 kHz to 300 GHz. Radio waves are mainly use for communication. Wifi uses radio technology. 4
  5. 5. FLAVOURS OF WIFI IEEE 802.11, is a set of standards to allow different devices to communicate wirelessly. It is created by the IEEE (pronounced eye-triple-e) LAN/MAN Standards Committee. • IEEE 802.11b • IEEE 802.11a • IEEE 802.11g • IEEE 802.11n IEEE 802.11 b  Appear in late 1999  Operates at 2.4GHz radio spectrum  11 Mbps (theoretical speed) - within 30 m Range  4-6 Mbps (actual speed)  100 -150 feet range  Most popular, Least Expensive  Interference from mobile phones and Bluetooth devices which can reduce the transmission speed. IEEE 802.11 a  Introduced in 2001  Operates at 5 GHz (less popular)  54 Mbps (theoretical speed  15-20 Mbps (Actual speed)  50-75 feet range  More expensive  Not compatible with 802.11b 5
  6. 6. IEEE 802.11 g  Introduced in 2003  Combine the feature of both standards (a,b)  100-150 feet range  54 Mbps Speed  2.4 GHz radio frequencies  Compatible with ‘b’  Use OFDM Technology (OFDM is a orthogonal frequency division multiplexing. It is basically a method of encoding digital data on multiple carrier frequencies) IEEE 802.11 n  Introduced in 2009  Uses multiple antennas that function in a "MIMO" mode ( multiple-input multipleoutput)  2.5 GHz and 5 GHz radio frequency  150 Mbps speed  Range up to 230 feet indoor 6
  7. 7. APPLICATIONS OF WIFI These are the placese where wifi is used o Home o Small Businesses or SOHO o Large Corporations & Campuses o Health Care o Wireless ISP (WISP) o Travelers Many devices can use wi-fi e.g. personal computers, video-game consoles, smartphones, some digital cameras, tablet computers and digital audio players. These can connect to a network resource such as the Internet via a wireless network access point. ADVANTAGES OF WI-FI 1. Wi-Fi is a core technology in GPS Industries Applications. 2. Wi-Fi technology available in hotels, airports, etc., will be more inclined to bring laptop with us when traveling for personal reasons. 3. Frees network devices from cables, allows for a more dynamic network to be grown. 1. Changes the way people live, communicate, work and play. 4. Many reliable and bug-free Wi-Fi products on the market 2. 5.It helps to become more productive at home, like online shopping and banking; 5. Wi-Fi technology allows getting out of home office and working in other rooms. 7
  8. 8. DISADVANTAGES OF WI-FI 1. 1.The 802.11b and 802.11g flavors of Wi-Fi use the 2.4 GHz spectrum, which is crowded with other devices such as Bluetooth, microwave ovens, cordless phones, or video sender devices, among many others. 2. 2.Power consumption is fairly high compared to other standards, making battery life and heat a concern. 3. 3.It is not always configured properly by users. CONCLUSION As Wi-Fi is now shipped in millions of products and deployed in millions of homes, business and hotspots worldwide, the technology has moved beyond the realm of a computer feature. Wi-Fi has fast become a cultural phenomenon. 8
  9. 9. SEMINAR – II WIFI Technology 9
  10. 10. CONTENTS:  Elements of WIFI  Walkie Talkie Network  WIFI's Radio Technology  Working of WIFI  Communication in WIFI  Adding WIFI to a computer  WIFI's network topologies  Conclusion 10
  11. 11. Elements of a WI-FI Network  Access Point (AP) - The AP is a wireless LAN transceiver or “base station” that can connect one or many wireless devices simultaneously to the Internet.  Wi-Fi cards - They accept the wireless signal and relay information. They can be internal and external. (e.g PCMCIA Card for Laptop and PCI Card for Desktop PC)  Safeguards - Firewalls and anti-virus software protect networks from uninvited users and keep information secure. Wi-Fi’s Walkie-Talkie Network To understand the wire less technology let us consider a pair of Walkie-Talkies.These are small radios that can transmit and receive radio signals.When we talk into a WalkieTalkie, our voice is picked up by a microphone, encoded onto a radio frequency and transmitted with the antenna. Another Walkie-Talkie can receive the transmission with its antenna, decode our voice from the radio signal and drive a speaker. Simple Walkie-Talkies like this transmit at a signal strength of about 0.25 watts, and they can transmit about 500 to 1,000 feet. If we want to connect two computers together in a network using Walkie-Talkie technology. Equip each computer with a Walkie-Talkie. Give each computer a way to set whether it wants to transmit or receive. Give the computer a way to turn its binary 1s and 0s into two different beeps that the walkie-talkie could transmit and receive and convert back and forth between beeps and 1s/0s. This would actually work. The only problem would be that the data rate would be very slow. Walkie-talkie is designed to handle the human voice.So it is not being able to send very much data in this way(may be 1,000 bits per second). 11
  12. 12. Wi-Fi's Radio Technology  WiFi radios that work with the 802.11b and 802.11g standards transmit at 2.4 GHz, while those that work with the 802.11a standard transmit at 5 GHz. Normal walkietalkies normally operate at 49 MHz. The higher frequency allows higher data rates.  WiFi radios use much more efficient coding techniques that also contribute to the much higher data rates. For 802.11a and 802.11g, the technique is known as orthogonal frequency-division multiplexing (OFDM). For 802.11b, it is called Complementary Code Keying (CCK).  The radios used for WiFi have the ability to change frequencies. 802.11b cards can transmit directly on any of three bands, or they can split the available radio bandwidth into dozens of channels and frequency hop rapidly between them. The advantage of frequency hopping is that it is much more immune to interference and can allow dozens of WiFi cards to talk simultaneously without interfering with each other. WORKING OF WIFI The most important items which makes Wi-Fi working in the laptop or desktop are  Radio Signals  Wi-Fi Card which fits in your laptop or computer.  Hotspots which create Wi-Fi Network. 12
  13. 13. o A Wi-Fi hotspot is created by installing an access point to an internet connection. o An access point acts as a base station. o When Wi-Fi enabled device encounters a hotspot the device can then connect to that network wirelessly. o A single access point can support up to 30 users and can function within a range of 100 – 150 feet indoors and up to 300 feet outdoors. o Many access points can be connected to each other via Ethernet cables to create a single large network. Radio Signals:  Radio Signals are the keys which make WiFi networking possible. These radio signals transmitted from Wi-Fi antennas are picked up by WiFi receivers such as computers and cell phones that are equipped with WiFi cards. Whenever a computer receives any of the signals within the range of a WiFi network which is usually 300 - 500 feet for antennas, the WiFi card will read the signals and thus create an internet connection between the user and the network without the use of a cord.  Access points which consist of antennas and routers are the main source which transmit and receive radio waves.  Antennas work stronger and have a longer radio transmission with a radius of 300500 feet which are used in public areas while the weaker yet effective router is more suitable for homes with a radio transmission of 100-150 feet. Wi-Fi Cards: You can think WiFi card as being an invisible cord that connects your computer to the antenna for a direct connection to the internet.  WiFi cards can be external or internal, meaning that if a WiFi card is not installed in your computer, you may purchase a USB antenna attachment and have it externally connect to your USB port, or have an antenna-equipped expansion card installed directly to the computer. For laptops, this card will be a PCMCIA card in which you insert to the PCMCIA slot on the laptop. 13
  14. 14. Wi-Fi Hotspots  A Wi-Fi hotspot is created by installing an access point to an internet connection. The access point transmits a wireless signal over a short distance . typically covering around 300 feet. When a Wi-Fi enabled device, such as a Pocket PC, encounters a hotspot, the device can then connect to that network wirelessly.  Most hotspots are located in places that are readily accessible to the public, like airports, coffee shops, hotels, book stores and campus environments. 802.11b is the most common specification for hotspots worldwide. The 802.11g standard is backwards compatible with .11b but .11a uses a different frequency range and requires separate hardware such as an a, a/g, or a/b/g adapter. The largest public Wi-Fi networks are provided by private internet service providers (ISPs) that charge a fee for users to connect to the internet. COMMUNICATION IN WI-FI Data exchange in Wi-Fi can be summarized into three phases: Phase I: Where data is prepared for transmission; it is encoded; changed into frames (digital signals are sent in frames for better QoS). The frequency for data transmission is also chosen depending upon the technique used to send the signals wirelessly. Phase II: Where data is transmitted with air as the medium of wave transmission 14
  15. 15. Phase III: Where data is received, decoded, acknowledged and then used. All of these phases apply some of the popular digital communications spread spectrum techniques for signal multiplexing (FHSS, Infrared, OFDM etc.), make use of security methods (WEP, WPA). Adding WiFi to a Computer Many new laptops come with a Wi-Fi card built in. It is also easy to add a Wi-Fi card to an older laptop or a desktop PC. The process is  Take a 802.11a, 802.11b or 802.11g network card. 802.11g has the advantage of higher speeds and good interoperability on 802.11b equipment.  For a laptop, this card will normally be a PCMCIA card that slide into a PCMCIA slot on laptop. Or take a small external adapter and plug it into a USB port.  For a desktop machine, take a PCI card & install inside the machine, or a small external adapter and connect to the computer with a USB cable.  Install the card  Install the drivers for the card  Find an 802.11 hotspot  Access the hotspot. 15
  16. 16. WI-FI NETWORK TOPOLOGIES 1. AP-based topology (Infrastructure Mode) 2. Peer-to-peer topology (Ad-hoc Mode) 3. Point-to-multipoint bridge topology AP-based topology (Infrastructure mode)  The client communicate through Access Point.  BSA-RF coverage provided by an AP.  ESA-It consists of 2 or more BSA.  ESA cell includes 10-15% overlap to allow roaming. Peer-to-peer TOPOLOGY  AP is not required.  Client devices within a cell can communicate directly with each other.  It is useful for setting up of a wireless network quickly and easily. 16
  17. 17. Point-to-multipoint bridge TOPOLOGY  This is used to connect a LAN in one building to a LANs in other buildings even if the buildings are miles apart. These conditions receive a clear line of sight between buildings. The line-of-sight range varies based on the type of wireless bridge and antenna used as well as the environmental conditions. Conclusion  Wi-fi is a simple, cost-effective way to connect to the Internet , Without the need to physically connecting wires.  Hotspot s a geographic area setup in any public location, and has a readily accessible wireless network  Security is a huge challenge for Wi-Fi Networks, many Security Techniques are used to improve it. The Future of Wi-Fi This is the graph of Hotels offering Wi-Fi. The future of Wi-Fi is very bright. Its growing in popularity because of decreasing cost and the freedom it gives to users. 17
  18. 18. SEMINAR – III WIFI Security 18
  19. 19. CONTENTS:  Need of security  Wi-Fi Security Threats  Security requirements  Security Techniques  Wi-Fi security tips  Conclusion 19
  20. 20. Security is essential part of Wifi Technology. Wi-Fi can be less secure than wired connections (such as Ethernet) because an intruder does not need a physical connection. Why security is more of a concern in wireless?  no inherent physical protection  physical connections between devices are replaced by logical associations  sending and receiving messages do not need physical access to the network infrastructure (cables, hubs, routers, etc.  ƒ broadcast communications  wireless usually means radio, which has a broadcast nature  transmissions can be overheard by anyone in range – anyone can generate transmissions,  • which will be received by other devices in range  • which will interfere with other nearby transmissions and may prevent their correct reception (jamming). Wi-Fi Security Threats Wireless technology doesn’t remove any old security issue, but introduces new ones o Eavesdropping o Man-in-the-middle attacks o Denial of Service 20
  21. 21. Eavesdropping Eavesdropping is the act of secretly listening to the private conversation of others without their consent.  Easy to perform, most impossible to detect  By default , everything is transmitted in clear text   -No secuirty offered by the transmission medium  Different tools available on the internet  -Network sniffers, protocol analysers   -Username, passwds,content... -Passwd collectors With the right equipment, it’s possible to eavesdrop traffic from few kilometres away Man In The Middle Attack An attack where a user gets between the sender and receiver of information and sniffs any information being sent.  Attacker spoofs a disassociate message from the victim  The victim starts to look for a new access point, and the attacker advertises his own AP on a different channel, using he real Aps MAC address  The attacker connects to the real  AP using victim’s MAC address 21
  22. 22. Denial of Service Denial-of-service attack (DoS attack) is an attempt to make a machine or network resource unavailable to its intended users.  Attack on transmission regency used    Frequency jamming Not very technical, but works Attack on MAC layer    Spoofed deauthentication / disassociatin messages Can target on specific user Attacks on higher layer protocol(TCP/IP protocol)  SYN Flooding Wireless communication security requirements  Confidentiality – messages sent must be encrypted  Authenticity – origin of messages received must be verified  Replay detection – freshness of messages received must be checked  Integrity – modifying messages on-the-fly (during radio transmission) is not so easy, but possible, Integrity of messages received must be verified  ƒ Access control – access to the network services should be provided only to legitimate entities SECURITY TECHNIQUES  Open/free/Unsecured (No Password)  WEP (Wired Equivalent privacy)  WPA (Wifi Protected access)  WPA II 22
  23. 23. Unsecured/Open Leaving your Wi-Fi unsecured is synonymous with leaving your front door wide open, so anyone could simply walk in. Leaving your Wi-Fi unsecured also transmits data packets between users and the router in unencrypted format, which makes these data packets easy to intercept and read. WEP (Wired Equivalent Privacy) WEP (Wired Equivalent Privacy) was the default encryption protocol introduced in the first IEEE 802.11 standard back in 1999. It is based on the RC4 encryption algorithm, with a secret key of 40 bits or 104 bits being combined with a 24-bit Initialisation Vector (IV) to encrypt the plaintext message M and its checksum – the ICV (Integrity Check Value). The encrypted message C was therefore determined using the following formula: C = [ M || ICV(M) ] + [ RC4(K || IV) ] where || is a concatenation operator and + is a XOR operator Figure : WEP encryption protocol 23
  24. 24. What’s wrong with WEP? IV values can be reused In fact the standard does not specify that the value needs to change at all. Reusing keys is a major cryptographic weakness in any security system. IV length is too short 24 bit keys allow for around 16.7 million possibilities. Sounds a lot, but on a busy network this number can be achieved in a few hours. Weak keys are susceptible to attack Certain keys value combinations, ’Weak IVs’, do not produce sufficiently random data for the first few bytes. This is the basis of the highly publicized attacks on WEP and the reason that keys can be discovered. Manufacturers often deliberately disallow Weak IV values. This is good in that it reduces the chances of a hacker capturing weak keys, but also has the effect of reducing the already limited key possibilities further, increasing the chance of reuse of keys. Master keys are used directly From a cryptographic point of view using master keys directly is not at all recommended. Master keys should only be used to generate other temporary keys. WEP is seriously flawed in this respect. Key Management and updating is poorly provided for Administration of WEP keys is not well designed and difficult to do on large networks. Users tend to change keys very infrequently which gives a potential hacker lots of time to collect enough packets to launch an attack. Message integrity checking is ineffective WEP does have a message integrity check but hackers can change messages and recompute a new value to match. This makes the checking ineffective against tampering. Conclusion Although WEP is far from an ideal security solution you should still use it. Some security is better than none. A determined attacker may be able to discover your keys given time and enough weak IVs, but that’s no reason to leave all of your doors open. 24
  25. 25. WPA (Wifi Protected access) Wi-Fi Protected Access, or WPA, was introduced to correct the inherent weaknesses of WEP. Although it does improve security, it has its own problems. The encryption key used by WPA relies on a passphrase, the service set identification name (SSID), SSID length and a random value. The majority of the information used to create this 256-bit key is readily known, so a would-be hacker needs only guess the passphrase to have access to the network. Dictionary attacks systematically attempt numerous combinations of words, characters and phrases to guess this passphrase. It was determined that a passphrase comprised of less than 20 characters could be defeated. TKIP packet is comprised of three parts:  1. A 128-bit temporal key that is shared by both clients and access points.  2. An MAC address of a client device.  3. A 48-bit initialization vector describes a packet sequence number. TKIP packet  This combination guarantees various wireless clients use different keys.  In order to be compatible with existing hardware, TKIP uses the same encryption algorithm (RC4) as WEP. As such, only software or firmware upgrade is required to implement TKIP. Compared with WEP, TKIP changes the temporal keys every10000 packets. This dynamic distribution leaves potential hackers little room to crack TKIP key.  In general, most security experts believe that TKIP is a stronger encryption than WEP. However, they also agree that TKIP should be an interim solution because of its use of RC4 algorithm. A summary of WPA benefits  In general, the security advantages of WPA over WEP are:  Apply stronger network access control through mutual authentication  Support better security technologies like 802.1X, EAP, RADIUS and preshared keys  Adopt dynamic keys in TKIP to establish better key management  Enforce data integrity through Michael Message Integrity Check  Provide forward compatibility to ultimate wireless security solution, 802.11i 25
  26. 26. WPA potential security issues:  There are still potential encryption weaknesses in TKIP. Fortunately, the successful crack is expected to be heavy and expensive.  Performance may be sacrificed potentially due to a more complex and computation intensive authentication and encryption protocols. WPA2 Wi-Fi Protected Access 2  Was ratified in 2004 as a solution to the key encryption problems contained in WEP and WPA.  A couple of small flaws appeared in WPA2, which require a quality of service attack or physical positioning between the user and router, but neither of these flaws are considered a severe threat that exposes user data.  WPA2 offers two encryption algorithms: AES and TKIP. TKIP is essentially WPA encryption, so for the benefits of WPA2 encryption, you should choose AES.  Another option on most routers is to choose both, which allows the stronger security of AES when applicable, but uses the weaker TKIP when compatibility issues arise. WIFI Security Tips Wireless networking can be kind of scary from a security standpoint. It opens up whole new attack vectors that were not present with wired network infrastructures. That doesn't mean you can't do it securely, however, and I aim to give you some ideas that can help you in that regard.  Don't broadcast your SSID. -  Use good wireless encryption. -WEP is not exactly "good" encryption. With a freely available tool like aircrack, you can sniff wireless traffic protected by WEP and crack security on that network in a matter of minutes. WPA is the current, common encryption standard you should probably be using -- though, of course, you should use something stronger as soon as it becomes available to you. Technology is advancing every day, on both sides of the encryption arms race, after all. 26
  27. 27.  Restrict access by MAC address. -restricting the MAC addresses allowed to connect to the network helps ensure you are not one of the "low hanging fruits" that people prefer to attack.  Shut down the network when it's not being used-If you have the sort of network that does not need to be running twenty-four hours a day, seven days a week, you can reduce the availability of it to security crackers by turning it off when it isn't in use.  Monitor your network for intruders. You should always make sure you have an eye on what's going on, that you are tracking attack trends. The more you know about what malicious security crackers are trying to do to your network, the better the job of defending against them you can do. Collect logs on scans and access attempts, use any of the hundreds of statistics generating tools that exist to turn those logs into more useful information, and set up your logging server to email you when something really anomalous happens.  Cover the bases. Make sure you have some kind of good firewall running, whether on a wireless router or on a laptop you use to connect to wireless networks away from home Is Wi-Fi Safe for Human? Wifi health effects on the human body are commonly dismissed because we love the convenience. Wi-Fi dangers are ignored. After all we can walk around our house with our laptop and not lose connection. No messy inconvenient cords. We can keep up with mails and conduct our work at coffee shops, airports, hotels, even hospitals. Who wants to give up ths kind of convenience? And yet, have we stopped to think about the fact that there was no safety testing conducted before it went into used. Here are some of the most common symptoms people report when exposed to microwave radiation from cell phones and towers  Chronic headaches  Memory Problems  Dizziness  Depression, Anxiety 27
  28. 28.  Sleep Disturbances  Tremors CONCLUSION Wireless security has undergone major evolutions in last 7 years. WEP, the original security standard, is widely considered as broken. The IEEE 802.11 Group, the Wi-Fi Alliance and major network equipment vendors like Cisco are all working together to develop a new level of security standards. 28
  29. 29. References SANS Institute InfoSec Reading Room www.sans.org/reading-room/whitepapers/wireless/evolutionwireless-security-80211-networks-wep-wpa-80211-standards1109 802.11ac: The Fifth Generation of Wi-Fi Technical White Paper http://www.cisco.com/en/US/prod/collateral/wireless/ ps5678/ps11983/white_paper_c11713103_ns767_Networking_Solutions White_Paper.html 29