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SIP Security Issues : The SIP Authentication Procedure and its Processing Load. Speaker: Lin-Yi Wu Advisor : Prof. Yi-Bing Lin Date : 2003/04/09. Main Reference.
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SIP Security Issues :The SIP Authentication Procedure and its Processing Load Speaker: Lin-Yi Wu Advisor : Prof. Yi-Bing Lin Date : 2003/04/09
Main Reference • Salsano, S.; Veltri, L.; Papalilo, D , “SIP security issues: the SIP authentication procedure and its processing load “, IEEE Network , Volume: 16 Issue: 6 , Nov/Dec 2002 • J. Rosenberg et al., “SIP: Session Initiation Protocol “ IETF RFC 3261, June 2002
Outline • Motivation • Classification of security • End-to-End • Hop-by-Hop • Security Support in SIP • Authentication • Encryption • Evaluation of Processing Cost • Proposed solution • Requirements • Limitation of current SIP security mechanism • Design concept
Motivation • Achieve the same security level in PSTN • High service availability • Prevent DOS, IDS, fault tolerance…etc. • Protection of user-to-network and user-to-user traffic • Authentication • Data Integrity • Encryption
Classification of security mechanism • End-to-End mechanism • Secure association between caller and callee user agent • Protect any confidential information besides route information • Hop-by-Hop mechanism • Secure association between two successive SIP entities in the path • Protect route information
Security Support in SIP • End-to-End mechanism • Defined in SIP protocol • Authentication • Proxy-Authenticate, Proxy-Authorization, WWW-Authenticate, Authorization • Encryption • S/MIME • Hop-by-Hop mechanism • Rely on Network level or Transport Level security • IPSec • TLS
Analysis : SIP Authentication Requirements • Requirements • Authentication • Mutual Authentication • Key Distribution • Roaming agreement • Integrity • Cipher Key exchange • Prevention of replay attack • Limitation of current Authentication mechanism • Authentication • Mutual Authentication : NO • Key Distribution : Predefine secret • Roaming agreement : NO • Integrity : achieve by S/MIME • Cipher Key exchange : NO • Prevention of replay attack : achieve by nonce
Concept of Design :Public/Private key based Authentication • The public key /private key of A : Pub_A/Pri_A • The public key /private key of B : Pub_B/Pri_B • A knows B’s public key Pub_B • B knows A’s public key Pub_A
Concept of Design : Certificate-based authentication (1/2) • Only CA’s public key has to be known.
Concept of Design : Certificate-based authentication (2/2) • Roaming agreement
Concept of Design : Certificate-based authentication (2/2) • Roaming agreement
Concept of Design: Examine the requirements • Examine the Requirements • Authentication • Mutual Authentication : YES • Key Distribution : base on Certificate verification • Roaming agreement : solved by PKI architecture • Integrity : S/MIME • Cipher Key exchange : can be achieved by public key & private key system • Prevention of replay attack : achieve by nonce • New type of Headers have to be specified.
S/MIME INVITE sip:bob@biloxi.com SIP/2.0 Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8 To: Bob <sip:bob@biloxi.com> From: Alice <sip:alice@atlanta.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314159 INVITE Max-Forwards: 70 Contact: <sip:alice@pc33.atlanta.com> Content-Type: application/pkcs7-mime; smime-type=enveloped-data; name=smime.p7m Content-Disposition: attachment; filename=smime.p7m handling=required Content-Type: application/sdp v=0 o=alice 53655765 2353687637 IN IP4 pc33.atlanta.com s=- t=0 0 c=IN IP4 pc33.atlanta.com m=audio 3456 RTP/AVP 0 1 3 99 a=rtpmap:0 PCMU/8000
SIP Header Privacy and Integrity using S/MIME : Tunneling SIP INVITE sip:bob@biloxi.com SIP/2.0 Via: SIP/2.0/UDP pc33.atlanta.com; branch=z9hG4bKnashds8 To: Bob <sip:bob@biloxi.com> From: Alice <sip:alice@atlanta.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314159 INVITE Max-Forwards: 70 Date: Thu, 21 Feb 2002 13:02:03 GMT Contact: <sip:alice@pc33.atlanta.com> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary=boundary42 Content-Length: 568 --boundary42 Content-Type: message/sip INVITE sip:bob@biloxi.com SIP/2.0 Via: SIP/2.0/UDP pc33.atlanta.com; branch=z9hG4bKnashds8 To: Bob <bob@biloxi.com> From: Alice <alice@atlanta.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314159 INVITE Max-Forwards: 70 Date: Thu, 21 Feb 2002 13:02:03 GMT Contact: <sip:alice@pc33.atlanta.com> Content-Type: application/sdp Content-Length: 147 v=0 o=UserA 2890844526 2890844526 IN IP4 here.com s=Session SDP c=IN IP4 pc33.atlanta.com t=0 0 m=audio 49172 RTP/AVP 0 a=rtpmap:0 PCMU/8000 --boundary42 Content-Type: application/pkcs7-signature; name=smime.p7s Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=smime.p7s; handling=required ghyHhHUujhJhjH77n8HHGTrfvbnj756tbB9HG4VQpfyF467GhIGfHfYT6 4VQpfyF467GhIGfHfYT6jH77n8HHGghyHhHUujhJh756tbB9HGTrfvbnj n8HHGTrfvhJhjH776tbB9HG4VQbnj7567GhIGfHfYT6ghyHhHUujpfyF4 7GhIGfHfYT64VQbnj756 --boundary42-
SIP Header Privacy and Integrity using S/MIME : Tunneling SIP INVITE sip:bob@biloxi.com SIP/2.0 Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8 To: Bob <sip:bob@biloxi.com> From: Anonymous <sip:anonymous@atlanta.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314159 INVITE Max-Forwards: 70 Date: Thu, 21 Feb 2002 13:02:03 GMT Contact: <sip:pc33.atlanta.com> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary=boundary42 Content-Length: 568 --boundary42 Content-Type: application/pkcs7-mime; smime-type=enveloped-data; name=smime.p7m Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=smime.p7m handling=required Content-Length: 231 ********************************************************* * Content-Type: message/sip * * INVITE sip:bob@biloxi.com SIP/2.0 * Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8 * To: Bob <bob@biloxi.com> * From: Alice <alice@atlanta.com>;tag=1928301774 * Call-ID: a84b4c76e66710 * CSeq: 314159 INVITE * Max-Forwards: 70 * Date: Thu, 21 Feb 2002 13:02:03 GMT * Contact: <sip:alice@pc33.atlanta.com> * Content-Type: application/sdp * v=0 * o=alice 53655765 2353687637 IN IP4 pc33.atlanta.com * s=Session SDP * t=0 0 * c=IN IP4 pc33.atlanta.com * m=audio 3456 RTP/AVP 0 1 3 99 * a=rtpmap:0 PCMU/8000 **********************************************