introduction to wireless security lecture 10. information and nework security2 outline n the...

Introduction to Wireless Introduction to Wireless SecuritySecurity

Lecture 10Lecture 10

Information and Nework Security 2

OutlineOutline

The importance of Wireless communications The importance of Wireless communications Wireless networks and security risksWireless networks and security risks

Why is it so hard to secure wireless communications?Why is it so hard to secure wireless communications? Wireless communications and network security issuesWireless communications and network security issues

WEPWEP WAPWAP Bluetooth (reading)Bluetooth (reading) WWAN and security (reading)WWAN and security (reading)

Principles for securing a wireless networkPrinciples for securing a wireless network What need to be done to secure a wireless network?What need to be done to secure a wireless network?


ReferencesReferences

http://www.practicallynetworked.com/thttp://www.practicallynetworked.com/tools/wireless_articles_security.htmools/wireless_articles_security.htm

http://www.cs.rice.edu/~astubble/wep/http://www.cs.rice.edu/~astubble/wep/wep_attack.pdfwep_attack.pdf

http://www.drizzle.com/~aboba/IEEE/http://www.drizzle.com/~aboba/IEEE/ http://www.hpl.hp.com/personal/Jean_http://www.hpl.hp.com/personal/Jean_

Tourrilhes/Linux/Tourrilhes/Linux/ http://www.cis.ohio-state.edu/~jain/refhttp://www.cis.ohio-state.edu/~jain/ref

s/wir_refs.htms/wir_refs.htm


Huge growth of wireless Huge growth of wireless communication devices, wireless communication devices, wireless laptops, PDA, handheld PC, Mobile laptops, PDA, handheld PC, Mobile phone, etc.phone, etc.

Pictures borrowed from other authors

Importance of wireless communicationsImportance of wireless communicationsGrowing of Wireless DevicesGrowing of Wireless Devices


Wireless Networks and Mobile Wireless Networks and Mobile Commerce servicesCommerce services

Wireless servicesm-commerce

Entertainment•Music•Games•Graphics•Video•etc

Communication•e-mail•Chatrooms•Video-conferencing•etc

Transactions•Banking•Broking•Shopping•Auctions•Betting•Booking & reservations•etc

Information•News•City guides•Directory services•Maps•Traffic & weather•Corporate information•etc


Wireless Communication UsageWireless Communication Usage

InternetInternet revolution has lead to the emergence of e- revolution has lead to the emergence of e-

commerce marketcommerce market

– Around 105 million Yahoo! subscribers in 2001Around 105 million Yahoo! subscribers in 2001

Expansion of Expansion of WirelessWireless devices has lead to the devices has lead to the

explosive growth of mobile communicationsexplosive growth of mobile communications

– More than 200 million wireless subscribers in More than 200 million wireless subscribers in

20012001

– Around 1 billion by 2004 (estimated)Around 1 billion by 2004 (estimated)

WirelessWireless & & Internet Internet convergence has lead to the convergence has lead to the

explosion of the Mobile Commerce marketexplosion of the Mobile Commerce market

– Very HighVery High number in the future! number in the future!


Wireless connectionsWireless connectionsEnd-to-End Simple Wireless LANEnd-to-End Simple Wireless LAN

WNICWNIC


Simple Wireless LAN (e.g)Simple Wireless LAN (e.g)

users

Access Point


WLAN Protocol SetupWLAN Protocol Setup

Access Point

Mobile Station

Mobile Station

Mobile Station

SharedKey

LAN


A Possible Wireless Network (e.g)A Possible Wireless Network (e.g)

Internet

users

e-businesses

Internet


Example of a WLANsExample of a WLANs

Try to find out if there is a WLAN on Try to find out if there is a WLAN on Caulfield campusCaulfield campus

Try to find out who else has a WLAN in Try to find out who else has a WLAN in Melbourne (in the city area)Melbourne (in the city area)

Check other university campuses, Check other university campuses, hotels with conference rooms, hotels with conference rooms, libraries, etc.libraries, etc.


Wireless Computing and Security Wireless Computing and Security

Wireless computing offers many benefits:Wireless computing offers many benefits:PortabilityPortabilityFlexibilityFlexibility Increased productivityIncreased productivityLower cost installationsLower cost installations

Wireless computing provides new working Wireless computing provides new working environments and imposes new security environments and imposes new security issues.issues.Protecting the networks against attacks, Protecting the networks against attacks,

ensuring secure data transmission, detecting ensuring secure data transmission, detecting and tracking down any penetration to a wireless and tracking down any penetration to a wireless network are difficult.network are difficult.


Wireless Communications and RisksWireless Communications and Risks

RisksRisksWireless technology has not advanced fast Wireless technology has not advanced fast

enough to allow better security mechanisms to enough to allow better security mechanisms to be implemented.be implemented.

Currently wireless traffic is not secureCurrently wireless traffic is not secure E.g: sensitive data may be transmitted over unsecured E.g: sensitive data may be transmitted over unsecured

connectionsconnections Credit Card numbersCredit Card numbers Corporate emailCorporate email Usernames/passwordsUsernames/passwords

Expert hackers can access wireless networks Expert hackers can access wireless networks easier than wired oneseasier than wired ones

Security holes in wireless systems can be Security holes in wireless systems can be quickly found with the ideas and tools that have quickly found with the ideas and tools that have been used with wired networksbeen used with wired networks


Wireless Network Security IssuesWireless Network Security Issues

Wireless devices are “radios” and Wireless devices are “radios” and have limitations in capacityhave limitations in capacityWireless communication medium is the Wireless communication medium is the

airwave and openly exposed to intrudersairwave and openly exposed to intrudersA wireless port of a wireless Local Area A wireless port of a wireless Local Area

Network (WLAN) is logically equivalent to Network (WLAN) is logically equivalent to an Ethernet port without any protectionan Ethernet port without any protection

Possible loss of confidentiality and Possible loss of confidentiality and integrity and the thread of denial of integrity and the thread of denial of serviceservice


Wireless LAN Security Issues (e.g)Wireless LAN Security Issues (e.g)

Cracking the encryption keyCracking the encryption key Reading and decrypting wireless LAN packets are not as hard as Reading and decrypting wireless LAN packets are not as hard as

in the case of wired networks due to the key generation problemsin the case of wired networks due to the key generation problems Unauthorised accessingUnauthorised accessing

An unregistered user can easily access to a wireless LAN An unregistered user can easily access to a wireless LAN resource if an Access Point is not correctly configured.resource if an Access Point is not correctly configured.

The user can also access to the main wired network via the The user can also access to the main wired network via the wireless LAN wireless LAN

Authorised users abusing the systems, eg:Authorised users abusing the systems, eg: Unauthorised sniffing of other traffic by usersUnauthorised sniffing of other traffic by users Eavesdropping on other users trafficEavesdropping on other users traffic

Setting up phantom Access Points to gather data from Setting up phantom Access Points to gather data from genuine usersgenuine users

Setting up an unknown wireless LAN inside a corporation => Setting up an unknown wireless LAN inside a corporation => making wired network more vulnerablemaking wired network more vulnerable


Wireless LAN Security - BackgroundWireless LAN Security - Background

Most Wireless Network Interface Card (WNIC) Most Wireless Network Interface Card (WNIC) and Access Point (AP) are used for WLANand Access Point (AP) are used for WLAN

Each WNIC or AP must be manually Each WNIC or AP must be manually configured with some shared keyconfigured with some shared key

The sending and receiving stations/AP share The sending and receiving stations/AP share a secret keya secret key

A sending station encrypts each frame before A sending station encrypts each frame before transmissiontransmission

Receiving station decrypts the frameReceiving station decrypts the frame


Wireless LAN Security - Wireless LAN Security - 802.x,802.x,802.11b (commercial name as WiFi),etc.802.11b (commercial name as WiFi),etc.

The 802.xThe 802.xFamily of standards set forth by IEEE to define Family of standards set forth by IEEE to define

the specifications for wireless LANs:the specifications for wireless LANs:

Wireless Medium Access Control (WMAC):Wireless Medium Access Control (WMAC): regulate access to the mediumregulate access to the medium Use 48 bits as Ethernet addresses on wired LANs Use 48 bits as Ethernet addresses on wired LANs

Physical Layer SpecificationsPhysical Layer Specifications Spectrum, distance, bit rate, etcSpectrum, distance, bit rate, etc


IEEE 802.X standardsIEEE 802.X standards

Borrowed from RFC


Security problems with WLANsSecurity problems with WLANs

Easy access: signals fly into the airEasy access: signals fly into the air Rouge Access PointRouge Access Point

Set up by experts or normal usersSet up by experts or normal users Unauthorised access to servicesUnauthorised access to services

Majority of access points are put in services with minimum Majority of access points are put in services with minimum modifications to their default configurationmodifications to their default configuration

Denial of servicesDenial of services Attackers can inject traffic into a wireless network without being Attackers can inject traffic into a wireless network without being

attached to an AP; A ping flood can be launched from a wired attached to an AP; A ping flood can be launched from a wired network to overwhelm the limited-capacity wireless devices network to overwhelm the limited-capacity wireless devices

WMAC spoofing and session hijackingWMAC spoofing and session hijacking Attackers can observe MAC addresses of stations and adopt Attackers can observe MAC addresses of stations and adopt

those addresses for malicious transmissionsthose addresses for malicious transmissions Traffic analysis and eavesdroppingTraffic analysis and eavesdropping

Frame headers can be transmitted in the clear form and are Frame headers can be transmitted in the clear form and are visible to anybody with a wireless network analyservisible to anybody with a wireless network analyser

Chain attacks to wired networks via a wireless oneChain attacks to wired networks via a wireless one


Wireless LAN Security - WEPWireless LAN Security - WEP

Wired Equivalent Privacy (WEP) Wired Equivalent Privacy (WEP) Designed by the IEEE aimed to prevent Designed by the IEEE aimed to prevent

eavesdroppers and unauthorised eavesdroppers and unauthorised connections to a wireless networkconnections to a wireless network

WEP tries to achieve similar security as a WEP tries to achieve similar security as a wired LANwired LAN Confidentiality: protect the contents of wireless traficConfidentiality: protect the contents of wireless trafic Access Control: prevent an adversary from using your Access Control: prevent an adversary from using your

wireless networkwireless network Data Integrity: prevent the modification of data in transitData Integrity: prevent the modification of data in transit


Security with WEPSecurity with WEP

RC4(iv,k)

iviv – the initialization vector, a random sequence of bits – the initialization vector, a random sequence of bits kk – the secret key – the secret key

RC4RC4 – – a stream cipher, believed to be securea stream cipher, believed to be secure Takes in an Takes in an initialization vector initialization vector and and keykey; produces a ; produces a key streamkey stream

ciphertexciphertex


Security with WEPSecurity with WEP

A secret key (k) shared between the communicating parties is distributed and each packet is encrypted with shared secret key + initialization vector (IV) [24 bits]

The sender: Computes a checksum c(M) Picks an IV v, and generate a keystream RC4(v,k) XORs <M,c(M)> with the keystream to get the ciphertext Transmits v and the ciphertext over the radio link Upon receipt, the receiver: Uses the transmitted v and the shared k to generate the

keystream RC4(v,k) XORs the ciphertext with RC4(v,k) to get <M',c'> Checks to see if c' = c(M') If it is, accepts M' as the message transmitted


WEP and Security IssuesWEP and Security Issues

The The keystreamkeystream for WEP is RC4(v,k), which depends for WEP is RC4(v,k), which depends only on v and k. k is a fixed shared secret, that is only on v and k. k is a fixed shared secret, that is rarely changedrarely changed

In many setups, many users share the same k In many setups, many users share the same k So the So the keystreamkeystream depends only on v depends only on v If two packets ever get transmitted with the same If two packets ever get transmitted with the same

value of v, you reuse the value of v, you reuse the keystreamkeystream, which is , which is vulnerable vulnerable

Since v gets transmitted in the clear form for each Since v gets transmitted in the clear form for each packet, an attacker can easily tell when a value of v packet, an attacker can easily tell when a value of v is reused is reused

How many possible values of v are there? v only How many possible values of v are there? v only occupies 24 bits of the header, so at most there are occupies 24 bits of the header, so at most there are 2^24 2^24

After 2^24 packets, there will be a repeat one!After 2^24 packets, there will be a repeat one!


Wireless LAN Security with WEPWireless LAN Security with WEP

Since IV is relatively short & shared keys Since IV is relatively short & shared keys that remain static, eventually WEP may use that remain static, eventually WEP may use the same IV for different data packets for a the same IV for different data packets for a large busy network in a short period of timelarge busy network in a short period of time

If you can collect enough packets based on If you can collect enough packets based on the same IV, you can work out the secret the same IV, you can work out the secret keykey

802.11 with WEP does not provide any 802.11 with WEP does not provide any functions that support the exchange of keys functions that support the exchange of keys among stations => system administrators or among stations => system administrators or users generally use the same keys for a users generally use the same keys for a long timelong time


WEP and its VulnerabilitiesWEP and its Vulnerabilities

WLAN tools that recover encryption keysWLAN tools that recover encryption keysExploits weakness in Key Scheduling Algorithm Exploits weakness in Key Scheduling Algorithm

of RC4of RC4Requires 5-10 million encrypted packetsRequires 5-10 million encrypted packetsOnce enough packets have been gathered, can Once enough packets have been gathered, can

guess the encryption key in under a secondguess the encryption key in under a secondFor more information:For more information:

http://airsnort.sourceforge.net/http://airsnort.sourceforge.net/ http://wepcrack.sourceforge.net/http://wepcrack.sourceforge.net/


Wireless attacks (e.g)Wireless attacks (e.g)

Session hijackingSession hijackingOccurs because of race conditions in 802.x and Occurs because of race conditions in 802.x and

802.x state machines802.x state machinesA hacker waits for successful authenticationA hacker waits for successful authenticationThen, breaks the user’s connection and Then, breaks the user’s connection and

impersonates herimpersonates herThe hacker can exploit the user’s session until The hacker can exploit the user’s session until

timeout timeout Man-in-the-MiddleMan-in-the-Middle

Since 802.x uses only one-way authentication a Since 802.x uses only one-way authentication a hacker can act as an AP to usershacker can act as an AP to users

APs are trusted entities => bad design=> APs are trusted entities => bad design=> security problems for WLANssecurity problems for WLANs


WEP and Security ConcernsWEP and Security Concerns

802.x with WEP is not enough802.x with WEP is not enough Should put more things together for Should put more things together for

securitysecurity Need another encryption protocol Need another encryption protocol

provide better securityprovide better security ProblemsProblems

Need hardware accelerationNeed hardware accelerationOptimize for speed and efficiencyOptimize for speed and efficiencyTradeoff in security schemeTradeoff in security scheme


Wireless LAN Security – Enhanced WEPWireless LAN Security – Enhanced WEP

Digital Certificates can be used for Digital Certificates can be used for distributing keys dynamically to WLANdistributing keys dynamically to WLANSolves key re-use problemSolves key re-use problem

Enhance authentication between Enhance authentication between clients and APs via an authentication clients and APs via an authentication serverserver

Increase key length and change keys Increase key length and change keys after a certain number of framesafter a certain number of frames


Wireless Application Protocol (WAP)Wireless Application Protocol (WAP)

WAP tries to providesWAP tries to provides AuthenticationAuthentication ConfidentialityConfidentiality IntegrityIntegrity

WAP security gatewayWAP security gateway Server product dedicated to providing WTLS sessions Server product dedicated to providing WTLS sessions Works with today’s WAP phonesWorks with today’s WAP phones

WebServerWeb

Server

users

WAP Gateway

WTP/WTLSInternet

HTTP/SSL



Designed to provide Internet Designed to provide Internet connections for wireless users, connections for wireless users, particularly mobile phone usersparticularly mobile phone users

Employs WML, WTLSEmploys WML, WTLS Uses WAP Identity Module to provide Uses WAP Identity Module to provide

resistance to device-tamperingresistance to device-tampering



A WAP-enable mobile phone can execute an application that A WAP-enable mobile phone can execute an application that requests a URL or runs a script on a standard web serverrequests a URL or runs a script on a standard web server

The agent on the phone sends an URL requests to a WAP The agent on the phone sends an URL requests to a WAP gateway in the form specified by WTP (wireless Transaction gateway in the form specified by WTP (wireless Transaction Protocol)Protocol)

WAP gateway translates the request into HTTP request WAP gateway translates the request into HTTP request (if the (if the transmission is sent using WTLS, the gateway also translates the data into HTTPS)transmission is sent using WTLS, the gateway also translates the data into HTTPS)

The gateway forwards (or encrypts then forwards) the The gateway forwards (or encrypts then forwards) the (HTTP/HTTPS) request to the web server(HTTP/HTTPS) request to the web server

Web server processes the request and returns the results to Web server processes the request and returns the results to the gateway (using HTTP/SSL) the gateway (using HTTP/SSL)

The gateway receives the results and does necessary The gateway receives the results and does necessary translations (if it is not done by a WAP server) and translations (if it is not done by a WAP server) and decryptionsdecryptions

The gateway then sends the results to the phoneThe gateway then sends the results to the phone


WAP SecurityWAP Security

The security of WAP systems is left to The security of WAP systems is left to architects and developersarchitects and developers

WTLS does not provide end-to-end securityWTLS does not provide end-to-end security WAP has common limitations as other WAP has common limitations as other

wireless technologies such as size, space, wireless technologies such as size, space, and speed.and speed.

WAP gateways are trusted to encrypt and WAP gateways are trusted to encrypt and decrypt datadecrypt data

WML and WML script are limited subsets of WML and WML script are limited subsets of languages with known security controllanguages with known security control


How about Using PKI to Enhance Security of How about Using PKI to Enhance Security of Wireless Environments?Wireless Environments?

users

e-businesses

Public Key Infrastructure can be used to enhance wireless security

Borrowed from Paul Ho


Problems with Using PKI to Enhance Problems with Using PKI to Enhance Security of Wireless Environments.Security of Wireless Environments.

Wireless devices may not have Wireless devices may not have sufficient power capacity to use PKI sufficient power capacity to use PKI for securityfor security

Applications may require fast Applications may require fast processingprocessing

Security protocols can employ private Security protocols can employ private key distribution to resolve the low-key distribution to resolve the low-computational power problemcomputational power problem


Secure a Wireless NetworkSecure a Wireless Network

Maintain a secure wireless network requires Maintain a secure wireless network requires significant effort and resources and we need to:significant effort and resources and we need to:

Develop an organisational security policy that addresses the use of all handheld devices

Ensure users on the network are fully trained in computer security awareness and the risks associated with handheld devices

Conduct ongoing, random security audits to monitor and track mobile devices

Ensure external boundary protection is in place around the perimeter of the building or buildings of the organisation

Deploy physical access controls to the building and other secure areas (e.g., photo ID, card badge readers, etc)



Label all handheld devices with the owner and organization's information

Ensure that users know where to report a lost or stolen device

Ensure that devices are stored securely when left unattended

Make sure that add-on modules are adequately protected when not in use

Enable a “power-on” password for each handheld device

Ensure proper password management (aging, complexity criteria, etc.) for all handheld devices



Synchronise devices with its corresponding PC regularly Delete sensitive data from the handheld device and archive it

on the PC when no longer needed on the handheld Turn off Infrared ports during periods of inactivity Install antivirus software on all handheld devices Install personal firewall software on all handheld devices Ensure that PDAs are provided with secure authorization

software/firmware Make sure that a user can be securely authenticated when

operating locally and remotely Use enterprise security applications to manage handheld

device security Ensure security assessment tools are used on handheld

devices


Key Security RequirementsKey Security Requirements

To be able to deal with wireless security problems, To be able to deal with wireless security problems, there are needs for:there are needs for:

Security from a wireless station or AP to Security from a wireless station or AP to A wireless networkA wireless networkA wired networkA wired network InternetInternet

From one wireless network to another From one wireless network to another A global standards-based open architecture for all A global standards-based open architecture for all

mobile devices is criticalmobile devices is critical Device and bandwidth independence regulations Device and bandwidth independence regulations

need to be enforcedneed to be enforced

introduction to wireless security lecture 10. information and nework security2 outline n the...

Documents

n wireless communications

wireless subscribers

wireless laptops

tourrilheslinux n http

wireless security lecture

tourrilheslinux http

simple wireless lan

possible wireless network