© Verizon Copyright June 12, 2015 Columbia - Verizon Research Collaboration Secure SIP: Scalable DoS and ToS Prevention Mechanisms for SIP-based VoIP Systems, and Validation Test Tools Sarvesh Nagpal, Eilon Yardeni, Henning Schulzrinne Columbia University Gaston Ormazabal Verizon Laboratories

© Verizon Copyright Agenda Discussion: A successful collaboration… –Value to Verizon Project Overview –Background, Research Focus, and Goals –DoS DoS Detection and Mitigation Strategy DoS Validation Methodology - DoS Automated Attack Tool –ToS ToS Integrity Verification Tool and Validation Methodology Intellectual Property Next Steps Conclusions

© Verizon Copyright Discussion… A “successful” collaboration

© Verizon Copyright A Successful Collaboration Want a realistic perspective on what makes projects succeed and what is unlikely to work –Industry must see value or need to pursue IP Rapid commercialization/productization “in house” or with an external industry partner –Agreement on fair distribution of rights/obligations Typical arrangement: GRA + professor –Who typically needs to supervise multiple projects at the same time –Often companies seem to have the illusion that they get the faculty's full attention... Require full attention of industry SME –Student mentoring/coaching »Industry perspective »Writing/Presentation skills –Manage Deliverables

© Verizon Copyright Deliverables Management Convert collective research insights into industry deliverables Clear understanding of deliverables –Standards –Reports –Systems/Prototypes Timelines –Start time and academic calendar –MS GRA vs. PhD

© Verizon Copyright Value to Verizon Intellectual Property with SIX Patent Applications Licensing Agreement –Taken research quickly into marketplace –Five vendors interested Enhanced VoIP security through standards and vendor involvement –Worked with Verizon vendors to mitigate exposures Rolled the requirements and lessons learned into the Verizon security architecture and new element requirements database for procurement –Columbia requirements valid for VoIP, Presence and Multimedia architectures Setup laboratory facilities for VoIP security evaluations and product development –In Columbia, prototype rapid development incubator –In Verizon, incorporated Columbia/Verizon collaborative test tools for a more realistic complex IP-routed laboratory environment

© Verizon Copyright Verizon Business Impact SIP DoS work impact on Verizon Business –Network & Information Security Organization “Better Security Reviews” of Advantage VoIP Service –Global Customer Service & Provisioning Organization Sales Engineering – Premier Accounts Team Briefing –Global Network Engineering & Planning Organization Support Technology organization to define new security architecture for VoIP Services SIP ToS work impact on Verizon Business –Office of Chief Financial Officer Credit&Collections

© Verizon Copyright Background & Research Focus SIP is the VoIP protocol of choice for both wireline and wireless telephony –Control protocol for the Internet Multimedia Systems (IMS) architecture VoIP services migrating to IP fast becoming attractive DoS and ToS targets –DoS attack traffic traversing network perimeter reduces availability of signaling and media for VoIP –Theft of Service must be prevented to maintain service integrity –Reduces ability to collect revenue and provider’s reputation both are at stake Attack targets –SIP infrastructure elements (proxy, softswitch, SBC, CSCF-P/I/S) –End-points (SIP phones) –Supporting services (e.g., DNS, Directory, DHCP, HSS, DIAMETER, Authorization Servers) Verizon needs to solve security problem for VoIP services –Protocol-aware application layer gateway for RTP –SIP DoS/DDoS detection and prevention for SIP channel –Theft of Service Architectural Integrity Verification Tool Need to verify performance & scalability at carrier class rates –Security and Performance are a zero sum game Columbia likes to work in real life problems & analyze large data sets –Goal of improving generic architectures and testing methodologies –Columbia has world-renowned expertise in SIP

© Verizon Copyright Goals Study VoIP DoS and ToS for SIP –Definition – define SIP specific threats –Detection – how do we detect an attack? –Mitigation – defense strategy and implementation –Validation – validate our defense strategy Generate requirements for future security network elements and prototypes –Share these requirements with vendors Generate the test tools and strategies for their validation –Share these tools with vendors

© Verizon Copyright VoIP Threat Taxonomy Scope of our research Scope of our research *- VoIP Security and Privacy Threat Taxonomy, VoIP Security Alliance Report, October, 2005 (

© Verizon Copyright Denial of Service & Theft of Service Denial of Service – preventing users from effectively using the target services –Service degradation to a “not usable” point –Complete loss of service Distributed Denial of Service attacks represent the main threat facing network operators* –Most attacks involve compromised hosts (bots) botnets sized from a few thousands to over million 25% of all computers on Internet may be botnets Theft of Service – any unlawful taking of an economic benefit of a service provider – With intention to deprive of lawful revenue or property *- Worldwide ISP Security Report, September 2005, Arbor Networks *- Criminals 'may overwhelm the web', 25 January, BBC

© Verizon Copyright DoS Mitigation Strategy Implementation flaws are easier to deal with –Systems can be tested before used in production –Systems can be patched when a new flaw is discovered –Attack signatures can be integrated with a firewall Application level and flooding attacks are harder to defend against –SIP infrastructure element defense Commercially available solutions for general UDP/SYN flooding but none for SIP  Address application level and flooding attacks specifically for SIP  Identify and address architectural weaknesses before they are exploited to commit ToS

© Verizon Copyright DoS Mitigation Solution Overview Untrusted DPPM sipd Trusted SIP RTP Filter IFilter II VoIP Traffic Attack Traffic Untrusted DPPM sipd Trusted SIP RTP Filter I Filter II

© Verizon Copyright Hardware Platform 10/100/100010/100 E1E1 E2E2 Backplane F0F0 C3C3 C4C4 Gigabit Ethernet Interconnects D0D0 D1D1 E1E1 E2E2 F0F0 C3C3 C4C4 D0D0 D1D1 3 4 P0P0 P0P0 System Level Port Distribution Application Server Module Pentium 1GHz ASM DPPM Intel IXP 2800 DPPM Intel IXP 2800

© Verizon Copyright Integrated DDOS and Dynamic Pinhole Filter DPPM InboundOutbound SIP Linux server Switch FCP/UDP Drop LookupCAM Dynamic Table Static TableCAM SIP DDOS TableCAM ASM sipd

© Verizon Copyright Integrated Testing and Analysis Environment GigE Switch SIP Proxy Call Handlers SIPUA/SIPp Controller secureSIP Attack Loaders SIPStone/SIPp Legitimate Loaders SIPUA/SIPp Firewall

© Verizon Copyright Theft of Service Overview VoIP is different –Not a static but a real-time application –Direct comparisons with PSTN According to Subex Azure 3% of total revenue is subject to “fraud”* VoIP can be expected to be at least twice as large a proportion of revenue –Theft of Service is more daunting problem in VoIP Implications of ToS –Lost revenue and bad reputation –Abused resources cause monetary losses to network providers –Unauthorized usage degrades whole system’s performance Scenarios –Using services without paying –Illegal Resource Sharing (unlimited-plans) –Compromised Systems –Call Spoofing and Vishing *Billing World and OSS Magazine: “Top Telco Frauds and How to Stop Them”, January 2007, by Geoff Ibett

© Verizon Copyright The Bigger Picture - Columbia VoIP Testbed Columbia VoIP test bed is collection of various open-source, commercial and home-grown SIP components –provides a unique platform for validating research Columbia-Verizon Research partnership has addressed major security problems –signalling, media and social threats Researched DoS solutions verified against powerful test setup at very high traffic rates ToS successfully validated integrity of different setups of test bed

© Verizon Copyright Intellectual Property – Six Patent Applications “Fine Granularity Scalability and Performance of SIP Aware Border Gateways: Methodology and Architecture for Measurements” –Inventors: Henning Schulzrinne, Kundan Singh, Eilon Yardeni (Columbia), Gaston Ormazabal (Verizon) “Architectural Design of a High Performance SIP-aware Application Layer Gateway” –Inventors: Henning Schulzrinne, Jonathan Lennox, Eilon Yardeni (Columbia), Gaston Ormazabal (Verizon) “Architectural Design of a High Performance SIP-aware DOS Detection and Mitigation System” –Inventors: Henning Schulzrinne, Eilon Yardeni, Somdutt Patnaik (Columbia), Gaston Ormazabal (Verizon) “Architectural Design of a High Performance SIP-aware DOS Detection and Mitigation System - Rate Limiting Thresholds” –Inventors: Henning Schulzrinne, Somdutt Patnaik (Columbia), Gaston Ormazabal (Verizon) “System and Method for Testing Network Firewall for Denial of Service (DoS) Detection and Prevention in Signaling Channel” –Inventors: Henning Schulzrinne, Eilon Yardeni, Sarvesh Nagpal (Columbia), Gaston Ormazabal (Verizon) “Theft of Service Architectural Integrity Validation Tools for Session Initiation Protocol (SIP) Based Systems” –Inventors: Henning Schulzrinne, Sarvesh Nagpal (Columbia), Gaston Ormazabal (Verizon)

© Verizon Copyright External – Publications, Presentations, Recognition Presentation at NANOG 38 – Oct (HS/GO) –“Securing SIP: Scalable Mechanisms for Protecting SIP-Based VoIP Systems ” Authors: Henning Schulzrinne, Eilon Yardeni, Somdutt Patnaik (Columbia), Gaston Ormazabal (Verizon) –Paper approved for publication in NANOG Proceedings –Made a headline in VON Magazine on October 11, 2006: Presentation to at Global 3G Evolution Forum – Tokyo, Japan, Jan (GO) Presentation at IPTComm 2007 – New York City, July, 2007 (GO) Presentation at OSS/BSS Summit – Tucson, AZ, September, 2007 (GO) Paper in development for current work (to be presented at IPTComm 2008) –“Secure SIP: A scalable prevention mechanism for DoS attacks on SIP based VoIP systems” Authors: Henning Schulzrinne, Eilon Yardeni, Sarvesh Nagpal (Columbia), Gaston Ormazabal (Verizon) Work incorporated in a new Masters level course on VoIP Security taught at Columbia in Fall 2006 –COMS : Special Topics in Computer : VoIP Security (HS) CATT Technological Impact Award

© Verizon Copyright Recommended Next Steps Conversion of research into a product that Verizon can use –Verizon needs to determine optimal architectural placement of DoS prevention functionality for VoIP and Presence Security Security vs. Performance Hardware vs. Software Implementation –Proxy/Softswitch (SW) –SBC or New network element (HW/SW) Use internally (protect VZ Network) Use externally (sell new security services to large customers) Need rapid commercialization –Licensing Agreement with equipment manufacturers –Exclusive vs. Non-exclusive Continue relationship with Columbia –Research in related areas Proposal to study SRTP –Maintain the testbeds for further research and to assist in product development during product testing cycle –Feedback loop of research and product cycle –Get other companies interested to synergize resources and share results What can we see doing to make the working relationship even more productive?

© Verizon Copyright Conclusions Research Results –Demonstrated SIP vulnerabilities for VoIP resulting in new DoS and ToS susceptibility Work is fully reusable to secure a “Presence” infrastructure –Implemented some “carrier-class” mitigation strategies Developed generic requirements Remove SIP DoS traffic at carrier class rates Prototype is first of its kind in the world –Built a validation testbed to measure performance Developed customized test tools Built a high powered SIP-specific Dos Attack tool in a parallel computing distributed testbed –Crashed a SIP Proxy in seconds Built a Theft of Service Architectural Integrity Validation Tool using parallel computing Intellectual Property –Worked resulted in six patent applications Commercialization –Licensing agreements currently under negotiation –Revenue both to Columba and Verizon –Need to socialize new requirements and test tools with vendor community to address rapid field deployment Vendors generally very interested in new requirements Rapid implementation is now expected

© Verizon Copyright Thank You Thank you Questions?

© Verizon Copyright Backup Slides…

© Verizon Copyright SIP Security Overview Application Layer Security –SIP RFC 2543 – little security –SIP RFC 3261 – security enhancements Digest Authentication TLS IPSec –SRTP/ZRTP (RFC 3711) Perimeter Protection –SIP aware Filtering Mechanisms –SIP aware DOS Protection Detection and Mitigation

© Verizon Copyright SIP Security Overview - ?? Application layer security Digest Authentication, TLS, S/MIME, IPSec, certificates SRTP/ZRTP for media Convergence leads to converged attacks –Data network attacks DDoS, spoofing, content alteration, platform attacks –Voice over IP network attacks Toll fraud, session hijacking, theft of service, spam/spit Most security problems are due to –User Datagram Protocol (UDP) instead of TCP/TLS –Plain text instead of S/MIME –Message/Method vulnerability –Flexible grammar --> syntax-based attacks

© Verizon Copyright Dynamic Pinhole Filtering SIP/ OK From: c=IN IP m=audio RTP/AVP 0 INVITE From: c=IN IP m=audio RTP/AVP 0 CAM Table SIPUA User2 SIPUA User : :56432

© Verizon Copyright SIP DoS and ToS Attack Taxonomy DoS –Implementation flaws –Application level –Flooding ToS –Billing Threats –Authorization Threats –Service Threats

© Verizon Copyright Strategy Focus VULNERABILITY : Most security problems are due to: –flexible grammar  syntax-based attacks –Plain text  interception and modification –SIP over UDP  ability to spoof SIP requests Registration/Call Hijacking Modification of Media sessions SIP ‘Method’ vulnerabilities –Session teardown –Request flooding –Error Message flooding RTP flooding STRATEGY: Two DoS detection and mitigation filters and ToS tools –SIP: Two types of rule-based detection and mitigation filters –Media: SIP-aware dynamic pinhole filtering –ToS Architectural Integrity Verification Tool Application Level Flooding

© Verizon Copyright SIP Detection and Mitigation Filters Authentication Based - Return Routability Check –Require SIP built-in digest authentication mechanism Null-authentication (no shared secret) –Filter out spoofed sources Method Specific Based – Rate Limiting –Transaction based Thresholding of message rates –INVITE –Errors State Machine sequencing –Filter “out-of-state” messages –Allow “in-state” messages –Dialog based Only useful in BYE and CANCEL messages Dynamic Pinhole Filtering for RTP Only signaled RTP media channels can traverse perimeter –Obtain from SDP interception End systems are protected against flooding of random RTP

© Verizon Copyright Test Tools SIPp, SIPStone, and SIPUA are benchmarking tools for SIP proxy and redirect servers –Establish calls using SIP in Loader/Handler mode –A controller software module (secureSIP) wrapped over SIPp/SIPUA/SIPStone launches legitimate and illegitimate calls at a pre-configured workload SIPp –Robust open-source test tool / traffic generator for SIP –Customizable XML scenarios for traffic generation –5 inbuilt timers to provide accurate statistics –Customized to launch attack (SIP DoS) traffic designed to cause proxy to fail SIPStone continuously launches spoofed calls which the proxy is expected to filter –For this project enhanced with: Null Digest Authentication Optional spoofed source IP address SIP requests SIPUA Test Suite –Has built-in Digest Authentication functionality –Sends 160 byte RTP packets every 20ms Settable to shorter interval (10ms) if needed for granularity –Starts RTP sequence numbers from zero –Dumps call number, sequence number, current timestamp and port numbers to a file

© Verizon Copyright secureSIP Control Architecture

© Verizon Copyright secureSIP Test Results for DoS Firewall Filters OFFFirewall Filters ON Traffic Composition Good CPS Attack CPS CPU Load Good CPS Attack CPS CPU Load Non-Auth Traffic Auth Good Traffic Auth Good Traffic + Spoof Traffic Auth Good Traffic + Flood of Requests Auth Good Traffic + Flood of Responses Auth Good Traffic + Flood of Out-of- State Concurren t Calls Call rate (CPS) Delay due to Firewall Pinhole opening Pinhole closing SIP DoS Measurements (showing max supported call rates) Dynamic Pinhole