1、 ETSI TR 133 969 V15.0.0 (2018-07) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; Study on security aspects of Public Warning System (PWS) (3GPP TR 33.969 version 15.0.0 Release 15) TECHNICAL REPORT ETSI ETSI TR 133 969 V15.0.0 (2
2、018-07)13GPP TR 33.969 version 15.0.0 Release 15Reference RTR/TSGS-0333969vf00 Keywords GSM,LTE,SECURITY,UMTS ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregist
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9、ociation. ETSI ETSI TR 133 969 V15.0.0 (2018-07)23GPP TR 33.969 version 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is pub
10、licly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETS
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13、se or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Report (TR) has been produced by ETSI 3rd Generation Partner
14、ship Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI iden
15、tities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verbs terminology In the present document “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expre
16、ssion of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TR 133 969 V15.0.0 (2018-07)33GPP TR 33.969 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 7g31 Scope
17、 8g32 References 9g33 Abbreviations . 10g34 Recommendations on security requirements of PWS 12g35 System architecture of PWS . 13g36 Security features of PWS . 13g36.1 PWS threats and analysis . 13g36.1.1 General 13g36.1.2 PWS Security circumvention attack . 14g36.1.3 Spoofing, tampering, and suppre
18、ssing 15g36.1.4 Threats to the delivery of the public key . 15g36.1.5 Location of node protecting the public key delivery in PWS . 15g36.2 Proposed security features of PWS 16g36.2.1 General 16g36.2.2 Restrictions on the PWS message signature length 18g36.2.2.1 General 18g36.2.2.2 Warning message fo
19、rmat in CMAS, KPAS, and EU-Alert . 18g36.2.2.3 Warning message format in ETWS . 18g36.2.2.4 Conclusion on signature length . 19g36.2.3 Algorithm agility of PWS . 20g36.2.3.1 General 20g36.2.3.2 ECDSA domain parameters 20g36.2.4 Security level and key length of signature algorithms proposed 22g36.2.5
20、 Verification of PWS Warning Notification message 24g36.2.5.1 General 24g36.2.5.2 Handling of Warning Notifications without signature 24g36.2.6 Primary and secondary notifications . 25g36.2.7 Network sharing impact to PWS Security 26g36.2.7.1 General 26g36.2.7.2 GWCN configuration 26g36.2.7.3 MOCN c
21、onfiguration 27g36.2.8 Triggering condition for public key update 28g36.2.9 Roaming impact to PWS Security 29g36.2.10 Discussion on parameters to be sent when distributing public keys or broadcasting warning messages . 31g36.2.10.1 Public Key Identifier (PKID) 31g36.2.10.2 Signing entity identifier
22、. 31g36.2.10.3 Signature Algorithm Identifier (SAI) 31g36.2.10.4 Domain parameters . 32g36.2.10.5 Domain set indicator . 32g36.2.10.6 Hash function indicator . 32g36.2.10.7 Network Security Use Counter (NSUC) . 32g36.2.10.8 Time stamp (Void) 32g36.2.10.9 CA ID (Void) 32g36.2.10.10 Conclusion 32g36.2
23、.11 Considerations on networks in disaster areas 34g37 Possible Security solutions of PWS . 34g37.0 General . 34g3ETSI ETSI TR 133 969 V15.0.0 (2018-07)43GPP TR 33.969 version 15.0.0 Release 157.1 Void 35g37.2 Void 35g37.3 Solution 3: NAS based solution . 35g37.3.1 General 35g37.3.2 PWS public key d
24、istribution . 35g37.3.2.1 Initial PWS public key distribution . 35g37.3.2.2 Core network PWS public key configuration 37g37.3.2.3 PWS public key update . 38g37.3.3 PWS Warning Notification message 39g37.3.4 Solutions to security issues in GSM/GPRS and with 2G subscribers in UMTS . 42g37.3.4.1 Genera
25、l 42g37.3.4.2 Re-use current GSM/GPRS security mechanism with initiating ciphering . 43g37.3.4.3 Enhanced integrity protection mechanism for GSM /GPRS . 45g37.3.4.4 Limiting key updates in GSM/GPRS 46g37.3.4.5 Mechanisms of NAS solution for GSM/GPRS . 46g37.3.4.6 Delaying public key update using a U
26、E-controlled timer . 46g37.4 Solution 4: GBA based protection 48g37.4.1 General 48g37.4.2 GBA based protection mechanism for public key distribution . 48g37.4.2.1 Key establishment . 48g37.4.2.2 Security protocol . 50g37.4.3 Transport mechanisms 51g37.4.3.1 Transport mechanisms for establishment of
27、GBA keys 51g37.4.3.2 Transport mechanisms for public key distribution 51g37.4.4 Analysis 53g37.4.4.1 Pros . 53g37.4.4.2 Cons 53g37.4.4.3 Cost . 53g37.4.4.4 Comparison to other solutions. 53g37.5 Solution 5: using NAS layer security . 54g37.5.1 High level solution discussion 54g37.5.2 Solution detail
28、s . 55g37.5.2.1 General 55g37.5.2.2 Changes in the mobility messages from the UE 55g37.5.2.3 Changes to the authentication procedure . 55g37.5.2.4 Changes to context transfers between core network nodes . 55g37.5.3 Comparison with other solutions 56g37.6 Solution 6: implicit certificate PKI based PW
29、S solution 57g37.6.1 General 57g37.6.1.1 CA updating via PWS test messaging . 58g37.6.1.2 CA updating via (U)SIM . 59g37.6.2 Certificate authorities 60g37.6.2.1 General 60g37.6.2.2 UE provisioning public key and CA-ID updating of home network . 61g37.6.2.3 Roaming considerations 62g37.6.3 Implicit c
30、ertificates . 63g37.6.3.1 High level view of an implicit certificate approach from the UE perspective 63g37.6.3.2 Generation of implicit certificate 64g37.6.3.3 PWS Security contents 65g37.6.4 Properties of solution 68g37.7 Solution 7: generalized certificate-based approach for PWS . 69g37.7.1 Intro
31、duction. 69g37.7.2 Structure of CAs . 70g37.7.2.1 Top-down approach to CAs 70g37.7.2.2 Bottom-up approach to CAs 70g37.7.2.3 More complex CA structures 70g37.7.2.4 Comparison with server certificates in other 3GPP specifications 71g37.7.3 Distribution of public root keys 72g37.7.3.1 Pre-installation
32、 in terminals at manufacturing time 72g37.7.3.2 Configuration when terminal is first taken into use 72g37.7.3.3 Public key update and revocation 72g37.7.3.4 Comparison with server certificates in other 3GPP specifications 72g3ETSI ETSI TR 133 969 V15.0.0 (2018-07)53GPP TR 33.969 version 15.0.0 Relea
33、se 157.7.4 Certificate format and distribution of certificates . 73g37.7.5 Considerations on pre-provisioned CAs public keys shared by CBEs . 74g37.8 Solution 8: national PWS solution based on UICC OTA . 76g37.8.1 Introduction. 76g37.8.2 Distribution of PWS public keys and parameters . 77g37.8.2.1 U
34、SIM file organization for PWS Security 77g37.8.2.2 UICC OTA message format 77g37.8.3 Format and handling of PWS notification 78g37.9 Solutions to counter the PWS Security circumvention attack and to mitigate the risk of displaying false unprotected warning messages . 79g37.9.0 General 79g37.9.1 Solu
35、tion A: No display of unauthenticated warning messages . 79g37.9.2 Solution B: Network-independent location verification . 80g37.9.3 Solution C: Using a UE-controlled timer 82g37.9.4 Recommendation 82g37.10 The use of signing proxies 83g38 Evaluation of different solutions 86g38.1 Evaluation of solu
36、tion 1 (Void) 86g38.2 Evaluation of solution 2 (Void) 86g38.3 Evaluation of solution 3 . 86g38.3.1 Public key length 86g38.3.2 NAS message consumption for public key . 86g38.3.3 Frequency of NAS message carrying public key 89g38.3.4 Number of CBEs / Signing proxy . 90g38.3.5 Evaluation of solutions
37、to security issues in GSM/GPRS and with 2G subscribers in UMTS . 92g38.3.5.1 General 92g38.3.5.2 Re-use current GSM/GPRS security mechanism with initiating ciphering . 92g38.3.5.3 Enhanced integrity protection mechanism for GSM /GPRS . 92g38.3.5.4 Limiting key updates in GSM/GPRS 93g38.3.5.5 Mechani
38、sms of NAS solution for GSM/GPRS . 93g38.3.5.6 Delaying public key update using a UE-controlled timer . 93g38.4 Evaluation of solution 4 (Void) 95g38.5 Evaluation of solution 5 (Void) 95g38.6 Evaluation of solution 6 and solution 7 95g38.6.1 Same points for both . 95g38.6.2 Specific points for impli
39、cit certificate based . 95g38.6.3 Specific points for generalized certificate based . 95g38.7 Evaluation of solution 7 (Void) 95g38.8 Evaluation of solution 8 . 96g38.9 Evaluation of signature algorithms in PWS . 96g38.9.1 General 96g38.9.2 Digital Signature Algorithm (DSA) 96g38.9.3 Elliptic Curve
40、Digital Signature Algorithm (ECDSA) . 96g38.9.4 ECQV based . 97g39 Key issues for establishing service requirements and designing a PWS security system 98g310 Conclusion 99g3Annex A: Archived solutions . 100g3A.1 Solution 1 . 100g3A.1.1 Public key distribution 100g3A.1.2 Public key distribution in U
41、MTS . 102g3A.1.3 Signature algorithm agility . 103g3A.1.4 Distribution of signature algorithm identifier in UMTS . 104g3A.1.5 Verification of PWS Warning Notification message 105g3A.2 Solution 2 . 106g3A.2.1 General . 106g3A.2.2 Initial PWS key distribution . 106g3A.2.3 Network PWS key configuration
42、 107g3A.2.4 PWS key update . 107g3ETSI ETSI TR 133 969 V15.0.0 (2018-07)63GPP TR 33.969 version 15.0.0 Release 15A.2.5 Delivery of PWS Warning Notification message . 109g3Annex B: Threat discussion depending on the PWS settings in the UE relating to roaming 110g3Annex C: Change history 114g3History
43、115g3ETSI ETSI TR 133 969 V15.0.0 (2018-07)73GPP TR 33.969 version 15.0.0 Release 15Foreword This Technical Report has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may change following formal TSG
44、 approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approva
45、l; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI
46、 TR 133 969 V15.0.0 (2018-07)83GPP TR 33.969 version 15.0.0 Release 151 Scope The present document studies security features and mechanisms for protection against false Base Stations broadcasting False Warning Notifications. The default terminal behaviour is to accept all Warning Notifications even
47、if their authenticity is unknown (i.e. no security protection). The default terminal behaviour is therefore open to the presentation of false Warning Notifications issued by false BSs even in countries without a Public Warning System (PWS) deployed. Examples of false BS risks include, but are not li
48、mited to: g882 False Warning Notifications to induce panic; g882 Abuse of warning system broadcast channel to send advertising / spam. ETSI ETSI TR 133 969 V15.0.0 (2018-07)93GPP TR 33.969 version 15.0.0 Release 152 References The following documents contain provisions which, through reference in th
49、is text, constitute provisions of the present document. - References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. - For a specific reference, subsequent revisions do not apply. - For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. 1 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TS 22.26
