Long Term EvolutionLong Term Evolutionandand

its security infrastructure its security infrastructure

Fataneh SafaviehFataneh SafaviehMobile security Seminar,Bit,07.02.2011Mobile security Seminar,Bit,07.02.2011

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Outline

Introduction: some history &backgroundWhat is LTE?LTE-SAE Security: some highlightsHome(e)Node B Security

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Introduction:Introduction: some history & backgroundsome history & background

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Mobile Evolution

Improvements in mobile communication technology during the last two decades

The Mobile Broadband is as important as Internt

http://www.nsma.org/conf2008/Presentation/2-1045-Miyahara-LTE_Overview_NMSA%2021March08_final.pdf

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User Expectations

Highly desire of broadband acces everywhere1. Home, Office

2. Train, Aeroplane, Canteen, during the Breake

Ubiquity (anywhere, anytime) Higher voice quality Higher speed Lower prices Multitude of services

http://www.nsma.org/conf2008/Presentation/2-1045-Miyahara-LTE_Overview_NMSA%2021March08_final.pdf

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3GPP

The 3rd generation partnership project

A global partnership of six SDOs:

1. Europe ETSI

2. USA ATIS

3. China CCSA

4. Japan ARIB & TTC

5. Korea TTA

LTE The UMTS Long Term Evolution - Sesia, Toufik, Baker

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What is LTE?What is LTE?

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What is LTE?

The latest standard in the mobile network technology tree

A project of 3GPP & mainly built on 3GPP cellular systems´ family

May be referred as E-UTRA & E-UTRAN Has advanced new radio interface Circuit switched networksall-IP networks Broadband connectivity on the move 100Mbps(DL), 50Mbps(UL), ~10 ms Latency

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UMTS and LTE architecture

Extract from ”Towards Global Mobile Broadband” A White Paper from the UMTS Forum

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LTE key features

High Spectral Efficiency more customers, less costs

Co-existence with other standards Flexible radio planning (cell size of 5km30/100km) Reduced Latency less RTT, multi-player gaming,

audio/video conferencing Reduced costs for operators (OPEX & CAPEX) Increased data rates via enhanced air interface

(OFDMA,SC-FDMA,MIMO) All-IP environment SAE or EPC

key advantages of SAE

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LTE-SAE Security:LTE-SAE Security: some highlightssome highlights

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Security in the LTE-SAE Network

Security features in the network (from TS 33.401- Fig.4-1)

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Security features in the LTE-SAE Network

Five security feature groups defined in TS 33.401

(I): Network access security provides users with secure access to services protects against attacks on the access interface

(II): Network domain security enables nodes to exchange signaling- & user- data securely protects against attacks on the wire line network

(III): User domain security Provides secure access to mobile stations

(IV): Application domain security enables applications in the user & provider domains to exchnage messages

securely

(V): Visibility and configurability of security allows the users to learn whether a security feature is in operation

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Authentication & key agreement

HSS generates authentication data and provides it to MME

Challenge-response authentication and key agreement procedure between MME and UE

4th ETSI Security Workshop - Sophia-Antipolis , 13-14 January 2009

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Confidentiality & integrity of signaling

RRC signaling between UE and E-UTRAN NAS signaling between UE and MME S1 interface signaling

protection is not UE-specific optional to use

4th ETSI Security Workshop - Sophia- Antipolis,13-14 January 2009

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User plane confidentiality

S1-U protection is not UE-specific (Enhanced) network domain security mechanisms (based on IPsec) Optional to use

Integrity is not protected for various reasons, e.g.: performance limited protection for application layer

4th ETSI Security Workshop - Sophia- Antipolis, 13-14 January 2009

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Cryptographic network separation

Key hierarchy (TS 33.401 - Figure 6.2-1)

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Cryptographic network separation

Authentication vectors are specific to the serving network

AV’s usable in UTRAN/GERAN cannot be used in EPS

AV’s usable for UTRAN/GERAN access cannot be used for EUTRAN access

Solution by a “separation bit”

Rel-99 USIM is still sufficient for EPS access

ME has to check the “separation bit” (when accessing E-UTRAN)

4th ETSI Security Workshop - Sophia-Antipolis , 13-14 January 2009

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Home (e) Node B SecurityHome (e) Node B Security

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System architecture of H(e)NB

UE HNB SeGWinsecure link

Operator’s core network

Figure from draft TR 33.820

E-UTRAN air interface between UE and HeNBHeNB accesses operator’s core network via a Security GatewayThe backhaul between HeNB and SeGW may be insecure Operator’s core network performs mutual authentication with HeNB

via SeGWSecurity tunnel between HeNB and SeGW to protect information transmitted in backhaul link

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Common threats to H(e)NB

1. Physical tampering with H(e)NB

2. Fraudulent software update / configuration changes

3. Denial of service attacks against core network

4. Eavesdropping of the other user’s UTRAN or E-UTRAN user data

5. User cloning the H(e)NB authentication Token

From TR 33.820

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Security requirements to H(e)NB

1. Unprotected data should never leave a secure domain inside H(e)NB

2. Software updates and configuration changes for the H(e)NB shall be cryptographically signed (by operator or H(e)NB supplier) and verified configuration changes shall be authorized by H(e)NB operator or supplier

3. Unauthenticated traffic shall be filtered out on the links between the core network and the H(e)NB

4. New users should be required to explicitly confirm their acceptance before being joined to an H(e)NB

5. H(e)NB authentication credentials shall be stored inside a secure domain i.e. from which outsider cannot retrieve or clone the credentials

From TR 33.820

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References and ResourcesReferences and Resources

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References and Resources

A Long Term Evolution Downlink inspired channel simulator using the SUI 3Channel Model, Thesis of Sanjay Kumar Sarkar, August 2009

LTE The UMTS Long Term Evolution-

Sesia, Toufik, Baker (WILEY Publication) 2009 http://www.nsma.org/conf2008/Presentation/2-1045-Miya

haraLTE_Overview_NMSA%2021March08_final.pdf Towards Global Mobile Broadband” A White Paper

from the UMTS Forum, February 2008 TS 33.401

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References and Resources

4th ETSI Security Workshop- Sophia-Antipolis , 13-14 January 2009 TR 33.820 A Survey of Security Threats on 4G Networks,

Yongsuk Park and Taejoon Park Security in the LTE-SAE Network,

www.agilent.com/find/lte www.3gpp.org www.radio-electronics.com http://sites.google.com/site/lteencyclopedia

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