Countermeasures of Spam over Internet Telephony in SIP

Countermeasures of Spam over Internet Telephony in SIP. edu Campuses with My. SQL and LDAP Support Speaker: Chang-Yu Wu Adviser: Dr. Quincy Wu School: National Chi Nan University Unit: Graduate Institute of CSIE Date: 2007. 10. 24

Motivation n Session Initiation Protocol (SIP), is a signaling protocol for Internet conferencing, telephony, events notification and instant messaging. n What is Vo. IP Spam n The Vo. IP Spam in the Vo. IP networks is also called SPIT (Spam over Internet Telephony). n It refers to unsolicited calls over Vo. IP networks. 2

Related Work n Blacklists n These are lists of e-mail or machine addresses from which are known to send spam mails. n Whitelists n Lists of addresses from which all mails will be accepted. n Spam filtering tools n Spam. Assassin n http: //spamassassin. apache. org/ 3

SIP. edu n Build a community of Internet 2 schools that is experimenting with enterprise SIP services. n Users should not be burdened with device addresses. n The initial SIP. edu architecture works by integrating the legacy campus PBX and person directory. n The SIP. edu becomes the effective tools which spammers use for sending SPIT. 4

SIP. edu Architecture INVITE Alice (sip: bob@ncnu. edu. tw ) Ncnu. edu. tw DNS SRV query _sip. _udp. ncnu. edu. tw INVITE (sip: 4762@gw. ncnu. edu. tw) Telephone number where username=bob Bob’ phone 5

SIP. edu Architecture (cont) INVITE Alice (sip: bob@ncnu. edu. tw DNS SRV query ) _sip. _udp. ncnu. edu. tw Ncnu. edu. tw INVITE (sip: Bob@163. 22. 21. 83) REGISTER Bob’ phone (Contact: 163. 22. 21. 83) 6

SEMS n SEMS(SIP express media server) is an extensible media server which helps us adding voice services to our Vo. IP system。 SIP server INVITE 200 OK SMTP mail IP Telephone RTP SEMS SMTP server 7

LDAP n Lightweight Directory Access Protocol (LDAP) is an application protocol for querying and modifying directory services running over TCP/IP. Optimized for lookups n More easily extended n 8

System Architecture n Use SIP. edu to be the basic environment of system. n Support the function of the Voicemail in the system. Use SIP. edu? YES NO YES SIP phone ringing NO Campus phone ringing Voicemail Register? 9

Flow chart 10

Automatically add callee into the contact list (1) INVITE Alice Bob (6) INVITE Alice SIP Proxy Server Alice (5) Update Acknowledged (2) Find Bob’ s Contact list Contact xxx xxxxx (3) Save Alice’s data in Bob’ s contact list (4) Update Acknowledged Bob’ s contact list 11

Performance Measurement n Program codes n My. SQL modules in Open. SER n My. SQL commands from Unix shell scripts n LDAP commands from Unix shell scripts n Stress-test n Call setup scenario (powered by SIPp) n n Max Allowed Rate: 10, 000 calls Concurrent Calls: 0~8, 000 calls (with interval 200) Total calls: 20, 000 calls Duration time: 30 s 12

Call Failure Rate 13

Future work n Information transmission n Improve call method of storing and searching data. n Add data into contact list n Design an interface that allows users to revise the contact list by themselves. 14

Q&A n Thanks for your coming! 15