Secure Telephony Enabled Secure Telephony Enabled Middle-box (STEM) Middle-box (STEM) Maggie Nguyen Maggie Nguyen Dr. Mark Stamp Dr. Mark Stamp SJSU - CS 265 SJSU - CS 265 Spring 2003 Spring 2003 STEM is proposed as a solution to network vulnerabilities, targeting the transmitting of real-time data over enterprise networks.
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Secure Telephony Enabled Middle-box (STEM) Maggie Nguyen Dr. Mark Stamp SJSU - CS 265 Spring 2003 STEM is proposed as a solution to network vulnerabilities,
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STEM Security Countermeasures DoS Attack Eavesdropping
IP Telephony ComponentsIP Telephony Components1. Gateways2. Gatekeepers3. IP Telephones4. PC-based Software
Phones5. MCUs
IP Telephony ProtocolsIP Telephony Protocols
Internet Engineering Task Force (IETF): Signaling: Session Initiation Protocol (SIP) Transport: Real Time Protocol (RTP) Media Description: Session Description Protocol (SDP)
International Telecommunications Union (ITU): Signaling: H.323 Codecs: G.711 (PCM), G.729, … ISDN: Q.931
STEM architecture is currently using the network required for SIP STEM architecture is currently using the network required for SIP deployment.deployment.
How SIP WorksHow SIP Works – SIP Call Setup– SIP Call Setup
Denial of Service TCP SYN Floods detected by Flow Monitor. SIP INVITE Floods detected by Protocol Parser. Malicious RTP Streams detected by Flow Monitor. M/S Gateway Voice Port saturation.
Eavesdropping Control Flow: STEM uses secured communication
protocols among SM, firewall, M/S gateways. Data Flow: STEM replies on application protocols
(SIP or H.323) to implement payload encryption.
ReferencesReferences
International Engineering Consortium. H.323.http://www.iec.org/online/tutorials/h323/
Reynolds, B. Challenges Challenges and Rewards in Enterprise Deployments of IP Telephony Presentation. http://networks.cs.ucdavis.edu/~ghosal/Research/Talks/IP-Tel-Netlab%20talK%20-%20rev%202.ppt
Reynolds, B. Deploying IP Telephony in an Enterprise and the Vulnerabilities that Come With It Presentation. http://seclab.cs.ucdavis.edu/secsem2/ReynoldsSeminar.ppt
Reynolds, B. and D. Ghosal. STEM: Secure Telephony Enabled Middlebox. IEEE Communications Magazine Special Issue on Security in Telecommunication Networks. October 2002http://www.off-pisteconsulting.com/research/pubs/ieee_comm.pdf