Voice over Internet Protocol (VoIP) Security


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  • Premise; Agreement that the future IP network will be a convergent services network. Agreement that there is value to incorporating VoIP into the IP network. VoIP Enabled PBXs are “different” than server based VoIP systems. Fundamental question is to consider the impact of incorporating VoIP into a convergent IP network architecture, specifically in regards to security. Start the dialog on issues, mechanisms, policies, etc. leading to “best practices”.
  • Key is understanding the affect of a mix of services (data, voice, video, mobile) on a single IP based network architecture. There is experience, in particular with data traffic, but less with VoIP and video. Just emerging is the impact of mobile wireless devices on the convergent IP network.
  • Not a comprehensive list. Most are traditional issues, but E-911 is a issue directly related to the introduction of VoIP.
  • An extended example is QoS.
  • Example Jitter buffers, 150 ms one-way latency. 802.1p/Q VLAN tagging standard embedded QoS also in IP telephones (layer 2). Differentiated Services (DiffServ) at Layer 3 100 Mbps desktop and 1 Gbps backbone
  • Snooping- eavesdropping. With authenticated access to the specific VLAN to which IPT packets are assigned and the ability to defeat the Data Link Layer (2) protection mechanisms that defend against these menaces, it might be possible to intercept unencrypted RTP packets. UDP is not much help at the network layer. Intercept at the switch by mirroring the port traffic. Digital certificates incorporated into an increasing array of devices, including telephone handsets, can ensure that device process only those commands that originate from trusted sources.
  • Voice over Internet Protocol (VoIP) Security

    1. 1. Voice over Internet Protocol (VoIP) Security Affects on the IP Network Architecture [email_address] Conference ICS – Wireless Group Meeting Tempe, Arizona February 6, 2005 Jose J. Valdes, Jr. Colorado State University
    2. 2. Convergence <ul><li>“ Today’s networks are being architected with converged, real time, voice, data, and video applications in mind.” (1) </li></ul><ul><li>“ It is this ability to integrate voice, data, and video applications using a single network infrastructure that makes deployment of IP telephony platform a essential step toward creating a next-generation network.” (1) </li></ul><ul><li>The next-generation network has different and extended architectural requirements, in part because of VoIP, e.g., security. </li></ul>
    3. 3. VoIP Security <ul><li>“ Security must prevent theft of service, authenticate users, and repel a range of attacks from outside and inside the firewall.” (2) </li></ul><ul><li>“ With the introduction of VOIP, the need for security is compounded because now we must protect two invaluable assets, our data and our voice.” (3) (video and mobile). </li></ul><ul><li>“ The key to securing VOIP is to use the security mechanisms like those deployed in the data networks (firewall, encryption, anti-virus, pop-up protection, O.S. updates,etc.).” (3) </li></ul>
    4. 4. VoIP Security Challenges <ul><li>Quality of Service (QoS) </li></ul><ul><ul><li>Latency </li></ul></ul><ul><ul><li>Jitter </li></ul></ul><ul><ul><li>Packet loss </li></ul></ul><ul><li>Security Breaches </li></ul><ul><ul><li>Access </li></ul></ul><ul><ul><li>Disruption </li></ul></ul><ul><ul><li>Confidentiality and privacy </li></ul></ul><ul><li>Network Elements </li></ul><ul><ul><li>Denial of Service (DoS) </li></ul></ul><ul><ul><li>Power failure </li></ul></ul><ul><ul><li>Viruses, Trojan Horse </li></ul></ul><ul><ul><li>Physical security </li></ul></ul><ul><ul><li>Operating System </li></ul></ul><ul><ul><li>Life and Safety (E-911) </li></ul></ul><ul><ul><li>802.11 </li></ul></ul><ul><li>Protocols </li></ul><ul><ul><li>H.323 </li></ul></ul><ul><ul><li>SIP </li></ul></ul>
    5. 5. Quality of Service (QoS) <ul><ul><li>“ Quality of Service (QoS) refers to the capacity of a network to provide better service to selected network traffic over various technologies …, and IP routed networks …” (4) </li></ul></ul><ul><ul><li>Latency is the time it takes for data to get from the source to the destination and is introduced from various network and VoIP components, e.g., encryption encoding and decoding. </li></ul></ul><ul><ul><li>Jitter is introduced when data packets have different latency and packets become out of sequence. </li></ul></ul><ul><ul><li>Packet loss is when data packets do not arrive at the destination or arrive too late to be processed. </li></ul></ul><ul><ul><li>(4) </li></ul></ul>
    6. 6. QOS <ul><li>“ The key to conquering QoS issues like latency and bandwidth congestion is speed.” (3) </li></ul><ul><li>“… every facet of network traversal must be completed quickly in VoIP.” (3) </li></ul><ul><li>Firewalls/NAT traversal and traffic encryption/decryption are latency producers and network congestion generators, but must effective means to secure a network. The “good and bad news”. </li></ul>
    7. 7. Security Breaches <ul><ul><li>Access </li></ul></ul><ul><ul><ul><li>Unauthentication - intrusion detection and application access control </li></ul></ul></ul><ul><ul><ul><li>Protection and updating of administrative passwords </li></ul></ul></ul><ul><ul><li>Disruption </li></ul></ul><ul><ul><ul><li>Denial of Service (DoS) – VLAN, firewall, routers, digital certificates </li></ul></ul></ul><ul><ul><ul><li>Network congestion – QoS, increased bandwidth </li></ul></ul></ul><ul><ul><li>Confidentiality and Privacy </li></ul></ul><ul><ul><ul><li>Eavesdropping & IP spoofing </li></ul></ul></ul>
    8. 8. Network Elements <ul><ul><li>Denial of Service (DoS) – see slide # 7 </li></ul></ul><ul><ul><li>Power failure – UPS, generators </li></ul></ul><ul><ul><li>Viruses, Trojan Horse – application and O.S. patches and updates, security policies </li></ul></ul><ul><ul><li>Physical security – access controls, policies </li></ul></ul><ul><ul><li>Operating System – patches, updates </li></ul></ul><ul><ul><li>Life and Safety (E-911) – static IP address, relocation policies </li></ul></ul><ul><ul><li>802.11 evolving IP mobile devices or dual mode with cellular </li></ul></ul>
    9. 9. IP Security Profiles <ul><li>ITU – T H.234 v2 & v3 defines different security profiles for product interoperability under the H.323 suite of protocols’ Annex D, E, and F. Suite designed for real time audio, video, multimedia, and data. </li></ul><ul><li>SIP security features described in RFC 3261 (IETF). Designed for VoIP and updated for video and messaging. </li></ul><ul><li>Some will argue that these protocols were designed from different perspectives. </li></ul>
    10. 10. Bottom Line and Discussion <ul><li>Expectations for VoIP will be based on the performance and availability of legacy telephony systems!! </li></ul><ul><li>How will VoIP affect the IP network architecture? </li></ul><ul><li>Will “traditional” IP security mechanisms and policies be effective or detrimental to VoIP on a convergent network? </li></ul><ul><li>How to identify the accommodations or “trade offs” that will be acceptable in support of VoIP on a convergent network? </li></ul>
    11. 11. References <ul><li>Broadcom. “Critical Steps for Successful VoIP Deployment.” White Paper October 2004 Broadcom Corporation Irvine, CA. </li></ul><ul><li>Shore, Joel. “IP Telephony Security: An Overview.” NetworkWorld URL: [email_address] </li></ul><ul><li>Kuhn, R.D., Walsh, T.J., & Fries, S., “Security Considerations for Voice Over IP Systems: Recommendations of the National Institute of Standards and Technology.” National Institute of Standards and Technology, Gaithersburg, MD. January 2005. </li></ul><ul><li>Cisco. “Internetworking Technology Handbook.” 2003. URL: http://www.cisco.com/univercd/cc/td/doc/cisintwrk/ito_doc (26 October 2004) </li></ul><ul><li>Tucker, G.S., “Voice Over Internet Protocol (VoIP) and Security.” GIAC Security Essentials Certification (GSEC), v1.4c, option 1, 26 October 2004 </li></ul>