wireless networking chapter three WAN.pdf
- 1. SECURITY OF WIRELESS LOCAL AREA NETWORKS CHAPTER 3
- 2. • Security usually refers to ensuring that users can – perform only the tasks that they are authorized to do – Access only the information that they are authorized to have. – Security of Network, computer and information • Information Security: – Information security refers to the processes and methodologies which are designed and implemented to protect print, electronic, or any other form of confidential, private and sensitive information or data from unauthorized access, use, misuse, disclosure, destruction, modification, or disruption. – Wikipedia says, "Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification, or destruction. • Network security – Network security consists of the provisions and policies adopted to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources. – Network security involves the authorization of access to data in a network controlled by the network administrator. • Users choose or are assigned an ID and password or other authenticating information that allows them access to information and programs within their Introduction
- 3. • Computer security – Computer security is Information security as applied to computer and networks. – The field covers all the processes and mechanisms by which computer-based equipment, information and services are protected from unauthorized access, change or destruction. – Computer security refers to the security of computers against intruders (e.g., hackers) and malicious software (e.g., viruses) • Computer to be secured is attached to a network and the bulk of the threats arise from the network. • The goals of security are – To maintain integrity:- protected from unauthorized change – To protect confidentiality:- hidden from unauthorized access – To ensure availability:- available to an authorized entity when it is needed
- 4. Cont’d Introduction and Terminology • Cryptology: Cryptology is the science concerned with data communication and storage in secure and secret form • It is applied in implementing the Computer Security. • cryptography deals with designing the secret codes and ciphers whereas the science of cryptanalysis deals with "breaking" and reading secret codes and ciphers. • Code: A code is simply an unvarying rule for replacing a piece of information (e.g., letter, word, or phrase) with another object, but not necessarily of the same sort, e.g. ASCII. • Ciphers: Ciphers, as in the case of codes, also replace a piece of information (an element of the plaintext that may consist of a letter, word, or string of symbols) with another object. • Plaintext: The source information, written in incomprehensible binary stream of 1s and 0s is referred to as the plaintext
- 5. Cont’d Introduction and Terminology • Secret key: The secret information known only to the transmitter and the receiver which is used to secure the PLAINTEXT. • Encryption: The transformation of the plaintext under the control of the key into a cipher (also called ciphertext) is referred to as encryption. • Decryption: The inverse operation, by which a legitimate receiver recovers the concealed information from the cipher using the key, is known as decryption • Ciphertext: The encrypted form of the PLAINTEXT is known as CYPHERTEXT. • MONOALPHABETIC SUBSTITUTION : A method of encryption where a letter in the plaintext is always replaced by the same letter in the ciphertext. • POLYALPHABETIC SUBSTITUTION: A method of encryption where a letter in the plaintext is not always replaced by the same letter in the ciphertext.
- 6. I* Security Techniques: • Two techniques are prevalent today: i. Cryptography:- concealing the content of a message by enciphering ii. Steganography:- means concealing the message itself by covering it with something else. • a single secret key is used for both encryption and decryption. • the sender puts a message in a box and locks the box using a shared key; the receiver unlocks the box with the same key and takes out the message. • Common symmetric key encryption algorithms include DES (the Data Encryption Standard) and AES (the Advanced Encryption Standard). • Common asymmetric key encryption algorithms include RSA algorithm • The most popular hash functions are MD5 (Message Digest 5), which uses 128 bits and SHA1 (Secure Hash Algorithm 1), which uses 160 bits. • Digital signature: This is a means by which the sender can electronically sign the data and the receiver can electronically verify the signature.
- 7. Cont’d Security Attacks: • The three goals of security – confidentiality, integrity, and availability – can be threatened by security attacks. • Attacks threatening Confidentiality: In general, two types of attacks threaten the confidentiality of information: • Snooping:- refers to unauthorized access to or interception of data. • traffic analysis:- An unauthorized entity can obtain some other type information by monitoring online traffic. • Attacks threatening Integrity: The integrity of data can be threatened by several kinds of attacks: Modification : After intercepting or accessing information, the attacker modifies the information to make it beneficial to himself. Replaying: The attacker obtains a copy of a message sent by the user and later tries to replay it. • Attacks threatening Availability: We mention only one attack threatening availability: denial of service • Denial of service: It is a common attack, which may slow down or totally interrupt the service of a system.
- 8. Cont’d Security Attacks: • Passive vs. Active attacks: The attacks can be categorized into two groups: 1. Passive and 2. Active • Passive Attacks: In a passive attack, the attacker’s goal is just to obtain information. In this case, the attacker does not modify data or harm the system • It is difficult to detect this type of attack until the sender or receiver finds out about the leaking of confidential information • Active Attacks: An active attack may change the data and harm the system. • Attacks that threatens the integrity and availability are active attacks . • Active attacks are normally easier to detect than to prevent, because an attacker can launch them in a variety of ways.
- 9. Cont’d Common Security Threats: Compromised-key attack Network Denial-of-Service Attack Eavesdropping Identity Spoofing (IP Address Spoofing) Man-in-the-Middle Attack RTP (Real-time Transport Protocol) Replay Attack SPIM (Spam over Instant Messaging) Viruses and Worms
- 10. Cont’d Common Security Threats • Compromised-key attack: The attacker uses the key to decrypt encrypted data without the knowledge of the sender of the data. • Network Denial-of-Service Attack: The denial-of-service attack occurs when the attacker prevents normal network use and function by valid users. • Eavesdropping: Eavesdropping can occur when an attacker gains access to the data path in a network and has the ability to monitor and read the traffic. This is also called sniffing or snooping. If the traffic is in plain text, the attacker is able to read the traffic when the attacker gains access to the path. • Identity Spoofing (IP Address Spoofing): Spoofing occurs when the attacker determines and uses an IP address of a network, computer, or network component when not authorized to do so.
- 11. Cont’d Common Security Threats • Man-in-the-Middle Attack: A man-in-the-middle attack occurs when an attacker reroutes communication between two users through the attacker's computer without the knowledge of the two communicating users. • This can happen if an attacker can modify Active Directory to add his or her server as a trusted server or modify DNS to get clients to connect through the attacker on their way to the server. • RTP (Real-time Transport Protocol) Replay Attack: A replay attack occurs when a valid media transmission between two parties is intercepted and retransmitted for malicious purposes. • SPIM (Spam over Instant Messaging): SPIM is unsolicited commercial instant messages, or presence subscription requests. • Viruses and Worms: A virus is a unit of code whose purpose is to reproduce additional, similar code units. To work, a virus needs a host, such as a file, e- mail, or program.
- 12. Introduction target Denial of Service (DoS): attackers make resources (server, bandwidth) unavailable to legitimate traffic by overwhelming resource with bogus traffic 1. select target 2. break into hosts around the network (see botnet) 3. send packets to target from compromised hosts Bad guys: attack server, network infrastructure 1-12
- 13. Introduction Bad guys can sniff packets packet “sniffing”: – broadcast media (shared ethernet, wireless) – promiscuous network interface reads/records all packets (e.g., including passwords!) passing by A B C src:B dest:A payload wireshark software used for end-of-chapter labs is a (free) packet-sniffer 1-13
- 14. Introduction Bad guys can use fake addresses IP spoofing: send packet with false source address A B C src:B dest:A payload 1-14 … lots more on security (throughout, Chapter 8)
- 15. Access - Rogue AP Attack • Most clients will associate to the access point with the strongest signal. If an unauthorized AP, which is generally a rogue AP, has a strong signal, clients will associate to the rogue AP. • The rogue AP will have access to the network traffic of all associated clients. • The rogue AP can also use ARP and IP spoofing to trick clients into sending passwords and sensitive information.
- 16. Denial of service (DoS) • DoS is when an attacker disables or corrupts wireless networks, systems, or services, with the intent of denying the service to authorized users. • DoS attacks take many forms. • In most cases, performing the attack simply involves running a hack, script, or tool.
- 17. Eavesdropping • Eavesdropping is secretly or stealthily listening to the private conversation or communications of others without their consent. The practice is widely regarded as unethical, and may be illegal.
- 19. Alice playback attack: Trudy recordsAlice’s packet and later plays it back to Bob Network Security 8-36 Alice’s IP addr Alice’s password “I’m Alice” Alice’s IP addr OK Alice’s IP addr Alice’s password “I’m Alice”
- 20. • Wireless local are network security (WLAN security) is a security system designed to protect networks from the security breaches to which wireless transmissions are susceptible. • This type of security is necessary because – WLAN signals have no physical boundary limitations – prone to illegitimate access over network resources – resulting in the vulnerability of private and confidential data. – Network operations and availability can also be compromised in case of a WLAN security breech. • To address these issues – various authentication mechanisms – Encryption techniques – invisibility and other administrative controlling techniques are used in WLANs. • Business and corporate WLANs in particular require adequate security measures to detect, prevent and block piggybackers, eavesdroppers and other intruders. WLAN security
- 21. WLAN security technology includes: – Wired Equivalent Privacy (WEP): – WPA/WPA2 (WI-FI Protected Access): – Wireless Intrusion Prevention Systems/Intrusion Detection Systems: • Wired Equivalent Privacy (WEP): – An old encryption standard used to overcome security threats. – WEP provides security to WLAN by encrypting the information transmitted over the air so that only the receivers with the correct encryption key can decrypt the information. • WPA/WPA2 (WI-FI Protected Access): – Improved on WEP by introducing Temporal Key Integrity Protocol (TKIP). – RC4 encryption used – TKIP uses a temporal encryption key that is regularly renewed, making it more difficult to steal. • Wireless Intrusion Prevention Systems/Intrusion Detection Systems: – Intrusion detection and prevention focuses on radio frequency (RF) levels. This involves radio scanning to detect rogue access points or ad hoc networks to regulate network access. – Attacks against WEP include Bit Flipping, Replay Attacks, and Weak IV collection.
- 22. Authentication Process – Shared-Key ? next
- 23. Performance, interoperability and configuration of Wireless devices Performance:- various wireless standards have different in frequency data transfer and range Interoperability – Network Interoperability is the continuous ability to send and receive data among the interconnected networks, providing the quality level expected by the end user without any negative impact to the sending and receiving networks – 802.11a and 802.11b work on different frequencies, so little chance for interoperability – Can coexist in one network – HiperLAN/2 is not interoperable with 802.11a or 802.11b Configuration of wireless devices Configuration done to communicate with other devices and to enhance security. It is better to change the default setting while configuring wireless devices
- 24. The WLAN security wheel • An effective wireless security policy works to ensure that the network assets of the organization are protected from sabotage and from inappropriate access, which includes both intentional and accidental access. • All wireless security features should be configured in compliance with the security policy of the organization. • If a security policy is not present, or if the policy is out of date, the policy should be created or updated before deciding how to configure or deploy wireless devices.
- 25. Simple Steps to Secure Wi-Fi Network 1. Change the Administrative Password on your Wireless Routers. 2. Installing a Firewall. 3. Change the Default SSID Name and Turn off SSID Broadcasting. 4. Disable DHCP. 5. Replace WEP with WPA. How to Secure Wi-Fi Networks?
- 26. 1. Change the Administrative Password on your Wireless Routers. • Routers came with default password to provide easy access. • Changing those passwords is one of the first recommended steps to do. • Default passwords are posted on the vendor support sites. How to Secure Wi-Fi Networks?
- 27. 2. Installing a Firewall. • A firewall is the fence of your network from any unauthorized accessing • Can help in the protection of your PC by blocking or allowing the pass to your network. How to Secure Wi-Fi Networks?
- 28. 3. Change the Default SSID Name and Turn off SSID Broadcasting. • In Wi-Fi a service set identifier (SSID) is a code attached to all packets on a wireless network to identify each packet as a part of the network. • Changing SSID will necessitate the wireless client computers to enter the name of the SSID by hand before they can connect to the network. • But even though and because the data packets that are transmitted will include the SSID it may be discovered. How to Secure Wi-Fi Networks?
- 29. 4. Disable DHCP • Disable the “Dynamic Host Configuration Protocol” • Assign IP addresses to the client computers manually to restrict the access to the router to specific MAC addresses. How to Secure Wi-Fi Networks?
- 30. 5. Replace WEP with WPA • WEP “Wired Equivalent Privacy” is a security protocol, encrypting data transmitted over the wireless computer network to provide security and privacy, and to protect the vulnerable wireless link between clients and access points. • But as WEP is weak and can be cracked in about 3 minutes as the FBI showed in 2005 using some freely access tools, WPA “Wi-Fi Protected Access” which is more powerful using 128-bit encryption keys and dynamic session keys, must replace it to provide strong data protection. How to Secure Wi-Fi Networks?
- 31. Man-In-The-Middle Attack is one of the attacks that can’t be applied to wired networks, it’s just applicable to Wi-Fi. • Hackers can configure a rogue AP to imitate a legitimate AP. • Once the client is connected to the rogue AP, the hacker can perform any attack that involves modifying the packet stream. • Emails can be read, phishing attacks can be implemented etc... Wi-Fi Special attacks
- 32. • SECURITY OF WIRELESS LOCAL AREA NETWORKS • Summary • Configuration considerations-Avoid default configuration and default passwords • industry application- • physical configuration-locate AP in safe place • types of transmission –service availability-read to provide service –signal availability-network coverage –circuit availability –equipment availability • wireless network controls • protective security mechanisms • protection of mobile computing assets
- 33. • keeping pace with change • determining the value of information • computer security principles • protecting the mobile office • computer theft • theft of information • malicious code • eavesdropping • setting security policy
- 34. Summary • Security definition • Security of – Information – Computer – Network • Goal of security • Security terminology – Cryptology -Cryptography – Code -Cipher – Plan text -Secret key – Encryption -Decryption – Cipher text -Mono and poly alphabetic • Security Attacks – Snoopoing--------attacks confidentiality – Trafic analysis – Modefication-----Attacks Integrity – Replaying – Denial service ----Attacks Avilability
- 35. • Common Security Threats Compromised-key attack Network Denial-of-Service Attack Eavesdropping Identity Spoofing (IP Address Spoofing) Man-in-the-Middle Attack RTP (Real-time Transport Protocol) Replay Attack SPIM (Spam over Instant Messaging) Viruses and Worms • WLAN security – Important for – How to address? – Which organization needs • WLAN security Technology – WEP -WPA/WPA2 – Wireless Intrusion protection system/Wireless intrusion detection system • System configuration, performance and interoperability • WLAN Security wheel(Secure, monitor, test and Improve) • How to secure wifi Change the Administrative Password on your Wireless Routers. Installing a Firewall. Change the Default SSID Name and Turn off SSID Broadcasting. Disable DHCP. Replace WEP with WPA.
- 36. END!
- 37. CHAPTER 4 AN EMERGING MOBILE (CELLULAR) NETWORK SERVICE