chapter 7 -wireless network security.ppt

chapter 7 -wireless network security.

1. Chapter -7
Wireless Network
Security
Compiled by Mikiyas .A
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2. Outline
Introduction to wireless security
Examining wireless LAN vulnerabilities
Understanding WLAN security models
Securing wireless transmission using VPN
Wireless security policies
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3. Introduction to wireless security
Awirelessnetworkisanytypeofcomputernetworkthat
useswirelessdataconnectionsforconnectingnetworknodes.
Wirelessnetworksoperateusingradiofrequency
technology,afrequencywithintheelectromagneticspectrum
associatedwithradiowavepropagation
Concernsforwirelesssecurityaresimilartothosefoundina
wiredenvironment
Securityrequirementsarethesame:
•Confidentiality,integrity,availability,authenticity,
accountability
•Mostsignificantsourceofriskistheunderlying
communicationsmedium
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4. Examining wireless LAN vulnerabilities
Overthelasttwelveyears,802.11WirelessLAN’shave
maturedandreallyreshapedthenetworklandscape.
802.11nisnowrapidlyreplacingEthernetasthemethodof
networkaccess.
Therapidincreasementofmobiledeviceshasledtoa
tremendousneedforwirelesslocalareanetworks(WLAN),
deployedinvarioustypesoflocations,includinghomes,
educationalinstitutions,airports,businessoffices,
governmentbuildings,militaryfacilities,coffeeshops,book
storesandmanyothervenues.
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5. Cont..
However, the increased development of Wireless LAN has
increased the potential threats to the home user, small
businesses and the corporate world.
Unlike a wired network, a WLAN uses radio frequency
transmission as the medium for communication.
This necessarily exposes layer 1 and layer 2 to whoever can
listen into the RF ranges on the network. Wireless insecurity
has been a critical issue since Wired Equivalent Privacy
(WEP), an IEEE standard security algorithm for wireless
networks, was compromised.
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6. WLAN VULNERABILITIES
WirelessLANshavegainedmuchmorepopularitythan
wirednetworksbecauseoftheirflexibility,cost-effectiveness
andeaseofinstallation.
However,theincreasingdeploymentofWLANspresents
thehackerorcrackerwithmoreopportunities.Unlikewired
networks,WLANstransmitdatathroughtheairusingradio
frequencytransmissionorinfrared.
Currentwirelesstechnologyinuseenablesanattackerto
monitorawirelessnetworkandintheworstcasemayaffect
theintegrityofthedata.
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7. WLANsaresusceptibletovariousvulnerabilitiesduetotheir
inherentcharacteristicsandthetechnologiestheyrelyon.Some
commonWLANvulnerabilitiesinclude:
UnauthorizedAccess:WLANsaresusceptibletounauthorized
accessifpropersecuritymeasuressuchasstrongencryptionand
authenticationprotocolsarenotimplemented.Attackerscan
interceptwirelesssignalsandgainaccesstothenetwork,
potentiallycompromisingsensitivedata.
WeakEncryption:WeakencryptionmethodssuchasWEP
(WiredEquivalentPrivacy)arevulnerabletovariousattacks,
includingpacketsniffingandbruteforceattacks.It'sessentialto
usestrongencryptionprotocolslikeWPA2(Wi-FiProtected
Access2)orWPA3tomitigatethisvulnerability.
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8. DenialofService(DoS)Attacks:WLANsaresusceptibleto
DoSattacks,whereattackersfloodthenetworkwithan
excessiveamountoftraffic,causingittobecomeunavailable
tolegitimateusers.Thiscandisruptoperationsandleadto
serviceoutages.
Man-in-the-Middle(MitM)Attacks:MitMattacksinvolve
interceptingandpossiblyalteringcommunicationbetween
twopartieswithouttheirknowledge.InWLANs,attackers
canpositionthemselvesbetweentheclientandtheaccess
point,interceptingandmanipulatingdatatransmitted
betweenthem
WPSVulnerabilities:Wi-FiProtectedSetup(WPS)is
designedtosimplifytheprocessofconnectingdevicestoa
wirelessnetwork.However,someimplementationsofWPS
havebeenfoundtocontainvulnerabilitiesthatcanbe
exploitedbyattackerstogainaccesstothenetwork.
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9. Cont..
SSIDSpoofing:Attackerscansetupfakewirelessaccess
pointswiththesameServiceSetIdentifier(SSID)as
legitimatenetworkstotrickusersintoconnectingtothem.
Onceconnected,attackerscaneavesdroponnetworktraffic
orlaunchfurtherattacks.
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10. Understanding WLAN security models
WirelessLocalAreaNetwork(WLAN)securitymodelsare
frameworksdesignedtoprotectwirelessnetworksfrom
variousthreatsandvulnerabilities.
Understandingthesemodelsisessentialforimplementing
effectivesecuritymeasures.HerearethekeyWLANsecurity
models:
-WEP(WiredEquivalentPrivacy):
-WPA(Wi-FiProtectedAccess):
-WPA2(Wi-FiProtectedAccess2):
-WPA3(Wi-FiProtectedAccess3):
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11. WEP (Wired Equivalent Privacy)
WEP(WiredEquivalentPrivacy)isoneoftheearliest
securityprotocolsdevelopedforwirelessnetworks,
specificallyWirelessLocalAreaNetworks(WLANs).
However,WEPhasseveralsignificantvulnerabilitiesthat
renderitineffectiveasasecureencryptionmethod.Hereare
somekeypointsaboutWEP:
Encryption:WEPencryptsdatatransmittedoverthe
wirelessnetworkusingasharedkeymechanism.Itusesthe
RC4encryptionalgorithmwitha40-bitor104-bitkeysize.
RC4(RivestCipher4)isastreamcipherdesignedbyRon
Rivestin1987.It'soneofthemostwidelyusedstream
ciphersduetoitssimplicityandspeed.
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12. Encryption Procedure RC4
1.Theuserinputsaplaintextfileandasecretkey.
2.TheencryptionenginethengeneratesthekeystreambyusingKSA
andPRGAAlgorithm.
3.ThiskeystreamisnowXORwiththeplaintext,thisXORingisdone
bytebybytetoproducetheencryptedtext.
4.Theencryptedtextisthensenttotheintendedreceiver,theintended
receiverwillthendecryptedthetextandafterdecryption,thereceiver
willgettheoriginalplaintext.
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13. 13

14. Cont..
Weak keys:
Itallowsanattackertodiscoverthedefaultkeybeing
usedbytheAccessPointandclientstations
Thisenablesanattackertodecryptallmessagesbeing
sentovertheencryptedchannel.
IV (initialization vector) reuse and small size:
There are 2
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different IVs
On a busy network, the IV will surely be reused, if the
default key has not been changed and the original
message can be retrieved relatively easily.
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15. Cont..
SecurityFlaws:WEP'ssecurityflawsbecamewell-known
soonafteritsintroduction.Researchersdemonstratedthat
WEPcouldbecrackedwithinminutesusingfreelyavailable
tools.
Replacement:Duetoitsvulnerabilities,WEPhasbeen
largelydeprecatedandreplacedbymoresecureencryption
protocolssuchasWPA(Wi-FiProtectedAccess)andWPA2.
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16. WPA (Wi-Fi Protected Access)
New technique in 2002
Replacement of security flaws of WEP
Improved data encryption
Strong user authentication
Because of many attacks related to static key, WPA minimize
shared secret key in accordance with the frame transmission
Use the RC4 algorithm in a proper way and provide fast
transfer of the data before someone can decrypt the data.
While more secure than WEP, WPA is still susceptible to
certain attacks.
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17. WPA2 (Wi-Fi Protected Access 2)
BasedontheIEEE802.istandard
2versions:Personal&Enterprise
TheprimaryenhancementoverWPAistheuseoftheAES
(AdvancedEncryptionStandard)algorithm
TheencryptioninWPA2isdonebyutilizingeitherAESor
TKIP
ThePersonalmodeusesaPSK(Pre-sharedkey)&doesnot
requireaseparateauthenticationofusers
Theenterprisemoderequirestheuserstobeseparately
authenticatedbyusingtheEAPprotocol
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18. Cont..
WPA2 has immunity against many types of hacker
attacks
Man-in-the middle
Replay
Key collision
Weak keys
Packet forging
Dictionary attacks
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19. How to defend when using WPA
Passphrases–theonlywaytocrackWPAistosniffthe
passwordPMKassociatedwiththehandshakeauthentication
process,andifthispasswordisextremelycomplicateditwill
bealmostimpossibletocrack
PassphraseComplexity–selectarandompassphrasethatis
notmadeupofdictionarywords.Selectacomplex
passphraseofaminimumof20charactersinlengthand
changeitatregularintervals
Changerouterdefaultusernameandpassword
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20. Cont..
ChangetheinternalIPsubnetifpossible
ChangedefaultnameandhidebroadcastingoftheSSID
(ServiceSetIdentifier)
Noneoftheattackmethodsarefasteroreffectivewhena
largerpassphraseisused.
Restrictaccesstoyourwirelessnetworkbyfilteringaccess
basedontheMAC(MediaAccessCode)addresses
UseEncryption
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21. Securing wireless transmission using VPN
Virtualprivatenetwork(VPN)isanetworkthatusesa
publictelecommunicationinfrastructure,toprovideremote
officesorindividualuserswithsecureaccesstotheir
organization'snetwork.
TheVPNfollowsaclientandserverapproach.
ForconnectionstoanopennetworksuchasaWi-Fihotspot
andthosecommonlyprovidedbyhotels,Starbucks,
McDonaldsandsoon,
avirtualprivatenetwork(VPN)canbeagoodsecurity
solutiontodeliverconsistentprotectionoveranyinternet
connectionandprovideend-to-endsecurityonwireless
devices.
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22. Cont..
TheVPNclientsandVPNserversareusedinthreedifferent
scenarios
1.Supportremoteaccesstoanintranet.
2.Supportconnectionsbetweenmultipleintranetswithinthe
sameorganization.
3.Joinnetworksbetweentwoorganizations,formingan
extranet.
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23. Wireless security policies ?
Wirelessdevicesandnetworksenableun-tethered
communicationstomobileusers.
Improperlyinstalled,configuredormanagedwireless
technologypresentsasignificantrisktotheconfidentialityof
information.
Wirelessnetworksecurityreferstotheprotectionofwireless
networkhardware,software,andtheinformationcontained
inthemfromthreatscausedbytheinherentvulnerabilitiesin
thetechnologyanditsimplementation.
Thispolicyistoensurethatthedeploymentofwireless
networkingiscontrolledandmanagedinacentralizedwayto
providefunctionalityandoptimumlevelsofservicewhilst
maintainingnetworksecurity.
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24. Thank you!
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