Wireless Security – Let the Nightmare End! Steve Lamb IT Pro Security Evangelist ...

Wireless Security – Let the Wireless Security – Let the Nightmare End!Nightmare End!

Steve LambSteve Lamb

IT Pro Security Evangelist IT Pro Security Evangelist

http://blogs.technet.com/steve_lambhttp://blogs.technet.com/steve_lamb

[email protected]@microsoft.com

http://blogs.technet.com/steve_lamb

AgendaAgenda

What’s wrong with wireless out of the box?What’s wrong with wireless out of the box?

Protected Extensible Authentiction Protected Extensible Authentiction Protocol(PEAP)Protocol(PEAP)

Extensible Authentiction Protocol - Transport Extensible Authentiction Protocol - Transport Layer Security(EAP-TLS)Layer Security(EAP-TLS)

PKI ReferencesPKI References

"Best Practices for Implementing a Microsoft "Best Practices for Implementing a Microsoft Windows Server 2003 Public Key Infrastructure" Windows Server 2003 Public Key Infrastructure" on on http://www.microsoft.com/http://www.microsoft.com/pkipki

http://www.microsoft.com/pki


AgendaAgenda




The challengeThe challenge

Huge fear of wirelessHuge fear of wireless

Rooted in misunderstandings of securityRooted in misunderstandings of security

Wireless can be made secureWireless can be made secure

Takes workTakes work

Need to understand problemNeed to understand problem

Need to plan for secure solutionNeed to plan for secure solution

Securing WirelessSecuring Wireless

Need to control who and with what Need to control who and with what (authenticate)(authenticate)

Need to control what they access (authorise)Need to control what they access (authorise)

Ensure integrity of communications (Encrypt)Ensure integrity of communications (Encrypt)

Ensure safe transfer of credentials (Encrypt Ensure safe transfer of credentials (Encrypt Authentication)Authentication)

Need to audit and reportNeed to audit and report

WEP setup and RC4WEP setup and RC4

Secret key shared between access point and all Secret key shared between access point and all clientsclients

Encrypts traffic before transmissionEncrypts traffic before transmission

Performs integrity check after transmissionPerforms integrity check after transmission

WEP uses RC4, a stream cipherWEP uses RC4, a stream cipher

[key] XOR [plaintext] [key] XOR [plaintext] [ciphertext] [ciphertext]

[ciphertext] XOR [key] [ciphertext] XOR [key] [plaintext] [plaintext]

Common attacksCommon attacks

Bit-flipping (encryption ≠ integrity)Bit-flipping (encryption ≠ integrity)

Flipping bit Flipping bit nn in ciphertext flips same bit in plaintext in ciphertext flips same bit in plaintext

Statistical attacksStatistical attacks

Multiple ciphertexts using same key permit Multiple ciphertexts using same key permit determination of plaintext XORdetermination of plaintext XOR

Enables statistical attacks to recover plaintextEnables statistical attacks to recover plaintext

More ciphertexts eases thisMore ciphertexts eases this

Once one plaintext is known, recovering others is Once one plaintext is known, recovering others is trivialtrivial

WEP’s “defenses”WEP’s “defenses”

Integrity check (IC) fieldIntegrity check (IC) field

CRC-32 checksum, part of encrypted payloadCRC-32 checksum, part of encrypted payload

Not keyedNot keyed

Subject to bit-flipping Subject to bit-flipping can modify IC to make altered can modify IC to make altered message appear validmessage appear valid

Initialization vector (IV) added to keyInitialization vector (IV) added to key

Alters key somewhat for each packetAlters key somewhat for each packet

24-bit field; contained in plaintext portion24-bit field; contained in plaintext portion

Alas, this small keyspace guarantees reuseAlas, this small keyspace guarantees reuse

More IV problemsMore IV problems

Say an AP constantly sends 1500-byte packets at Say an AP constantly sends 1500-byte packets at 11mbps11mbps

Keyspace exhausted in 5 hoursKeyspace exhausted in 5 hours

Could be quicker if packets are smallerCould be quicker if packets are smaller

Key reuse causes even more collisionsKey reuse causes even more collisions

Some cards reset IV to 0 after initializationSome cards reset IV to 0 after initialization

Some cards increment by 1 after each packetSome cards increment by 1 after each packet

802.11 standard does 802.11 standard does notnot mandate new per- mandate new per-packet IV!packet IV!

Classes of attacksClasses of attacks

Key and IV reuseKey and IV reuse

Known plaintext attackKnown plaintext attack

Partial known plaintext attackPartial known plaintext attack

Weaknesses in RC4 key scheduling algorithmWeaknesses in RC4 key scheduling algorithm

Authentication forgingAuthentication forging

Realtime decryptionRealtime decryption

VPNsVPNs

ProsPros

FamiliarityFamiliarity

Hardware IndependentHardware Independent

Proven SecurityProven Security

ConsCons

Lacks user transparencyLacks user transparency

Only user logon (not Only user logon (not computer)computer)

Roaming profiles, logon Roaming profiles, logon scripts, GPOs broken, scripts, GPOs broken, shares, management shares, management agents, Remote desktopagents, Remote desktop

No reconnect on resume No reconnect on resume from standbyfrom standby

Complex network structureComplex network structure

VPNsVPNs

More ConsMore Cons

No protection for WLANNo protection for WLAN

Bottleneck at VPN Bottleneck at VPN devices devices

Higher management & Higher management & hardware costhardware cost

Prone to disconnectionProne to disconnection

Yet more cons! (non-MS Yet more cons! (non-MS VPNs)VPNs)

33rdrd party licensing costs party licensing costs

Client compatibilityClient compatibility

Many VPN auth Many VPN auth schemes (IPsec Xauth) schemes (IPsec Xauth) are as bad as WEP!are as bad as WEP!

AgendaAgenda

Public Key Infrastructure and Cryptography(PKI)Public Key Infrastructure and Cryptography(PKI)




PEAP encapsulationPEAP encapsulation

1. 1. Server authenticates to client

2. 2. Establishes protected tunnel (TLS)

3. 3. Client authenticates inside tunnel to server

No cryptographic binding between PEAP tunnel and tunneled authN No cryptographic binding between PEAP tunnel and tunneled authN methodmethod

Fix: constrain client (in GPO) to trust only a specific corporate root Fix: constrain client (in GPO) to trust only a specific corporate root CACA

Foils potential MitM attacksFoils potential MitM attacks

The many flavors of PEAP…The many flavors of PEAP…

Common point of customer confusion:Common point of customer confusion:

Microsoft released PEAPv0 (a.k.a MSFT-PEAP) while…Microsoft released PEAPv0 (a.k.a MSFT-PEAP) while…

Cisco released PEAPv1 (a.k.a Cisco-PEAP)Cisco released PEAPv1 (a.k.a Cisco-PEAP)

Support for PEAPSupport for PEAP

Most RADIUS servers on market now support PEAP version 0:Most RADIUS servers on market now support PEAP version 0:Cisco ACS (RADIUS server)Cisco ACS (RADIUS server)

Funk Steal Belted RADIUSFunk Steal Belted RADIUS

Interlink RADIUSInterlink RADIUS

MeetingHouse RADIUSMeetingHouse RADIUS

PEAP is supported in the following families:PEAP is supported in the following families:

Natively - Microsoft® Windows® 2003, Windows XPSP1+, Windows® Natively - Microsoft® Windows® 2003, Windows XPSP1+, Windows® 2000 SP4, Tablet2000 SP4, Tablet

Application or system upgrade - Windows 98, Windows NT 4.0 and Application or system upgrade - Windows 98, Windows NT 4.0 and Pocket PC 2002Pocket PC 2002

Internet Authentication Service (IAS) in Microsoft® Windows® 2000 Internet Authentication Service (IAS) in Microsoft® Windows® 2000 Server family and Windows Server® 2003 family support PEAPServer family and Windows Server® 2003 family support PEAP

no need to install third party RADIUS software. no need to install third party RADIUS software.

AgendaAgenda




EthernetEthernet

Access PointAccess Point

Radius ServerRadius Server

802.1X On 802.11802.1X On 802.11

EAPOL-StartEAPOL-Start

EAP-Response/IdentityEAP-Response/Identity

Radius-Access-ChallengeRadius-Access-Challenge

EAP-Response EAP-Response (credentials)(credentials)

Access blockedAccess blocked

AssociationAssociation

Radius-Access-AcceptRadius-Access-Accept

EAP-Request/IdentityEAP-Request/Identity

EAP-RequestEAP-Request

Radius-Access-RequestRadius-Access-Request

Radius-Access-RequestRadius-Access-Request

RADIUSRADIUS

Laptop computerLaptop computer

WirelessWireless

802.11802.11802.11 Associate802.11 Associate

EAP-SuccessEAP-Success

Access allowedAccess allowedEAPOL-Key (Key)EAPOL-Key (Key)

Secure Wireless Deployment Secure Wireless Deployment ComponentsComponents

Wireless ClientsWireless Clients

Wireless Access Wireless Access

PointsPoints

Radio Types: 802.11 a/b/gRadio Types: 802.11 a/b/g

Network Authentication: 802.1X, Network Authentication: 802.1X, WPA, WPA2/802.11i*WPA, WPA2/802.11i*

Encryption: WEP, TKIP, AESEncryption: WEP, TKIP, AES

RADIUS ServerRADIUS Server

RADIUSRADIUS

EAP/TLS EAP/TLS

PEAP-MSCHAPv2PEAP-MSCHAPv2

Remote Access PoliciesRemote Access Policies

User account User account databasedatabase

Remote Access permissionsRemote Access permissions

Credentials = PasswordsCredentials = Passwords

Certificate Authority Certificate Authority

(optional)(optional)Credentials = CertificatesCredentials = Certificates

Secure Wireless Deployment Secure Wireless Deployment MS OfferingsMS Offerings

Windows XPWindows XP

Windows Wireless Zero ConfigWindows Wireless Zero Config

Native 802.1X, WPA, and soon WPA2*Native 802.1X, WPA, and soon WPA2*

Certificates, Passwords, Smartcards, Certificates, Passwords, Smartcards, RSAToken**RSAToken**

Wireless group policyWireless group policy

APAP Any Access Point supporting 802.11 Any Access Point supporting 802.11 and 802.1X standardsand 802.1X standards

Server 2003 IASServer 2003 IAS

EAP/TLS (certificates/smartcard)EAP/TLS (certificates/smartcard)

PEAP (password)PEAP (password)

Remote access policiesRemote access policies

Radius proxy functionsRadius proxy functions

Improved scalingImproved scaling

Server 2003 Active Server 2003 Active Directory Directory

Wireless group policyWireless group policy

User and computer authenticationUser and computer authentication

Server 2003 Server 2003 Certificate Certificate Authority Authority

User and computer auto-enrollmentUser and computer auto-enrollment

Secure Wireless Deployment Secure Wireless Deployment BenefitsBenefits

Windows XPWindows XP

Integrated Windows ClientIntegrated Windows Client

Standards based securityStandards based security

Evolving with the industryEvolving with the industry

Seamless sign-on experienceSeamless sign-on experience

APAP InteroperabilityInteroperability

Server 2003 IASServer 2003 IAS

SecuritySecurity

ManageabilityManageability

Policy-based access managementPolicy-based access management

ScalabilityScalability

Deep and wideDeep and wide

Server 2003 Active Server 2003 Active DirectoryDirectory

Centralized AdministrationCentralized Administration

Client configurationClient configuration

Access managementAccess management

Server 2003 Server 2003 Certificate Certificate Authority Authority

Automated client updatingAutomated client updating

Hidden SSIDHidden SSID

Does not provide any real securityDoes not provide any real security

Easily discoverable in well-used environmentsEasily discoverable in well-used environments

Windows client experience is impactedWindows client experience is impacted

MAC FilteringMAC Filtering

Does not scaleDoes not scale

NIC management issueNIC management issue

MAC is spoofableMAC is spoofable

““Shared” modeShared” mode

Sounds like more security but is actually worseSounds like more security but is actually worse

Not to be confused with Pre-Shared Key (PSK) which is more secureNot to be confused with Pre-Shared Key (PSK) which is more secure

Open networks and VPN’sOpen networks and VPN’s

Grants Grants everyoneeveryone access to the wireless segment access to the wireless segment

Great for hotspots, not for your businessGreat for hotspots, not for your business

Security Best Practices Security Best Practices What What NOTNOT to do to do

Security Best Practices Security Best Practices What to doWhat to do

Chose a security authentication Chose a security authentication

WPA with EAP-TLS and both user and computer certificatesWPA with EAP-TLS and both user and computer certificates

WPA with PEAP-MS-CHAP v2 and enforce strong user passwordsWPA with PEAP-MS-CHAP v2 and enforce strong user passwords

WEP with 802.1X authentication, EAP-TLS with both user and WEP with 802.1X authentication, EAP-TLS with both user and computer certificates, and periodic re-authenticationcomputer certificates, and periodic re-authentication

WEP with 802.1X authentication, PEAP-MS-CHAP v2, periodic re-WEP with 802.1X authentication, PEAP-MS-CHAP v2, periodic re-authentication, enforce strong user passwordsauthentication, enforce strong user passwords

Preventing roguesPreventing rogues

User education and policyUser education and policy

Ongoing MonitoringOngoing Monitoring

Don’t use Hidden SSIDsDon’t use Hidden SSIDs

Do use Wireless Group Policy Do use Wireless Group Policy

Install at least two IAS RADIUS serversInstall at least two IAS RADIUS servers

For best performance, install IAS on domain controllersFor best performance, install IAS on domain controllers

Use strong RADIUS shared secretsUse strong RADIUS shared secrets

Use as many different RADIUS shared secrets as Use as many different RADIUS shared secrets as possiblepossible

Use IAS RADIUS proxies to scale authentication trafficUse IAS RADIUS proxies to scale authentication traffic

Use IAS RADIUS proxies for separate account Use IAS RADIUS proxies for separate account databasesdatabases

Best Practices: ScalabilityBest Practices: ScalabilityMicrosoft RADIUS – Internet Authentication Microsoft RADIUS – Internet Authentication Service (IAS)Service (IAS)

IAS servers

WirelessAPs

IASRADIUSproxies

Using IAS RADIUS proxiesUsing IAS RADIUS proxiesLoad balancing of RADIUS trafficLoad balancing of RADIUS traffic

IAS serversIAS servers

Forest 1 Forest 2

WirelessAPs

IASRADIUSproxies

Using IAS RADIUS proxiesUsing IAS RADIUS proxiesCross-forest authenticationCross-forest authentication

Best Practices: ManagementBest Practices: Management

Use the Wireless Network (IEEE 802.11) Policies Group Use the Wireless Network (IEEE 802.11) Policies Group Policy settings to automatically configure wireless clients Policy settings to automatically configure wireless clients running Windows XP and Windows Server 2003 with running Windows XP and Windows Server 2003 with your SSID your SSID

If you have a native-mode domain, use universal groups If you have a native-mode domain, use universal groups and global groups to organize your wireless computer and global groups to organize your wireless computer and user accounts into a single group. and user accounts into a single group.

Use certificate auto-enrollment for computer certificatesUse certificate auto-enrollment for computer certificates

Use certificate auto-enrollment for user certificatesUse certificate auto-enrollment for user certificates

"Best Practices for Implementing a Microsoft Windows "Best Practices for Implementing a Microsoft Windows Server 2003 Public Key Infrastructure" on Server 2003 Public Key Infrastructure" on http://www.microsoft.com/http://www.microsoft.com/pkipki..



Aligning with other security Aligning with other security initiatives initiatives

Network Health ComplianceNetwork Health Compliance

Lays down both the network infrastructure and ID Lays down both the network infrastructure and ID Management elements needed for NAP (Network Access Management elements needed for NAP (Network Access Protection)Protection)

Preserves investment in infrastructurePreserves investment in infrastructure

RADIUS is the center of policy making, enforcement and RADIUS is the center of policy making, enforcement and access control for Secure Wireless and NAPaccess control for Secure Wireless and NAP

Single sign-on Single sign-on

Secure Network SegmentationSecure Network Segmentation

IPSec and 802.1X work together by providing a defense in IPSec and 802.1X work together by providing a defense in depth strategydepth strategy

802.1X – hard outside – offers isolation802.1X – hard outside – offers isolation

IPSec – hard inside – offers resource protectionIPSec – hard inside – offers resource protection

Best Practices as applied to Best Practices as applied to MicrosoftMicrosoft

Microsoft IT Secure Wireless DeploymentMicrosoft IT Secure Wireless Deployment

Wireless ClientsWireless Clients


PointsPoints

23-30K per day23-30K per day

Network Authentication: 802.1XNetwork Authentication: 802.1X

300K authentications per day300K authentications per day

Encryption: dynamic WEPEncryption: dynamic WEP

~5000 802.11b Cisco APs~5000 802.11b Cisco APs

90 countries, 300+sites90 countries, 300+sites

Single SSIDSingle SSID

RADIUS ServerRADIUS Server Puget Sound 2 Proxy, 4 RADIUS Puget Sound 2 Proxy, 4 RADIUS serversservers

Worldwide 5 Proxy/RADIUS serversWorldwide 5 Proxy/RADIUS servers

EAP/TLS EAP/TLS

Remote Access Policies enforcedRemote Access Policies enforced

User account User account databasedatabase

Remote Access permissionsRemote Access permissions

Group Policies for configurationGroup Policies for configuration

Certificate Authority Certificate Authority User and Machine CertificatesUser and Machine Certificates

Autoenrolled Autoenrolled

Microsoft Future Wireless DeploymentMicrosoft Future Wireless DeploymentWireless ClientsWireless Clients


PointsPoints

Migration to 802.11i (WPA2)Migration to 802.11i (WPA2)

Thin AP/Wireless Switch Architecture Thin AP/Wireless Switch Architecture

Single Hardware PlatformSingle Hardware Platform

Multiple SSIDs, Independent servicesMultiple SSIDs, Independent services

Voice, Guest and Corporate NetworkVoice, Guest and Corporate Network

RADIUS ServersRADIUS Servers Independent RADIUS servers for Independent RADIUS servers for each serviceeach service

Different Auth methods for each Different Auth methods for each servicesservices

Proxies to distribute loadProxies to distribute load

User account databaseUser account database Multiple ADs to support Guests and Multiple ADs to support Guests and Corporate users.Corporate users.

Certificate Authority Certificate Authority User and Machine Certificates for User and Machine Certificates for corporate servicescorporate services

Autoenrolled Autoenrolled

ToolsTools

WEPCrack—breaks 802.11 keysWEPCrack—breaks 802.11 keys

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

AirSnort—breaks 802.11 keysAirSnort—breaks 802.11 keys

Needs only 5-10 million packetsNeeds only 5-10 million packets

http://airsnort.shmoo.com/http://airsnort.shmoo.com/

NetStumbler—access point reconnaissanceNetStumbler—access point reconnaissance

http://www.netstumbler.comhttp://www.netstumbler.com

ResourcesResources

The Advantages of Protected Extensible Authentication The Advantages of Protected Extensible Authentication Protocol (PEAP)Protocol (PEAP)

http://www.microsoft.com/windowsserver2003/techinfo/overviehttp://www.microsoft.com/windowsserver2003/techinfo/overview/peap.mspxw/peap.mspx

Designing and Deploying Wireless LAN Connectivity for Designing and Deploying Wireless LAN Connectivity for the Microsoft Corporate Networkthe Microsoft Corporate Network

http://www.microsoft.com/technet/prodtechnol/winxppro/deployhttp://www.microsoft.com/technet/prodtechnol/winxppro/deploy/wlandply.mspx/wlandply.mspx

"Best Practices for Implementing a Microsoft Windows "Best Practices for Implementing a Microsoft Windows Server 2003 Public Key Infrastructure" Server 2003 Public Key Infrastructure"

http://www.microsoft.com/http://www.microsoft.com/pkipki

Best Practices article in Technet Magazine – Nov 2005Best Practices article in Technet Magazine – Nov 2005

http://www.technetmagazine.comhttp://www.technetmagazine.com

http://www.microsoft.com/windowsserver2003/techinfo/overview/peap.mspx

http://www.microsoft.com/windowsserver2003/techinfo/overview/peap.mspx

http://www.microsoft.com/technet/prodtechnol/winxppro/deploy/wlandply.mspx

http://www.microsoft.com/technet/prodtechnol/winxppro/deploy/wlandply.mspx



http://www.technetmagazine.com/

© 2004 Microsoft Corporation. All rights reserved. This presentation is for informational purposes only.© 2004 Microsoft Corporation. All rights reserved. This presentation is for informational purposes only.MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS SUMMARY.MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS SUMMARY.

Wireless Security – Let the Nightmare End! Steve Lamb IT Pro Security Evangelist ...

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