sipcolumbiasymposium

© Verizon Copyright 2008. 1

April 13, 2023

Columbia - Verizon Research CollaborationColumbia - Verizon Research CollaborationSecure SIP: Scalable DoS and ToS Prevention Mechanisms for Secure SIP: Scalable DoS and ToS Prevention Mechanisms for SIP-based VoIP Systems, and Validation Test ToolsSIP-based VoIP Systems, and Validation Test Tools

Sarvesh Nagpal, Eilon Yardeni, Henning

Schulzrinne

Columbia UniversityColumbia University

Gaston Ormazabal

Verizon Verizon LaboratoriesLaboratories


AgendaAgenda

• 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


Discussion… A “successful” collaborationDiscussion… A “successful” collaboration

© Verizon Copyright 2008.

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


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


Value to VerizonValue 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 Business ImpactVerizon 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


Background & Research FocusBackground & 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


GoalsGoals

• 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


VoIP Threat Taxonomy VoIP Threat Taxonomy

Scope of our research - 2006

Scope of our research - 2007

*- VoIP Security and Privacy Threat Taxonomy, VoIP Security Alliance Report, October, 2005 (http://www.voipsa.org)


Denial of Service & Theft of ServiceDenial 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, 2007. BBC


DoS Mitigation StrategyDoS 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


DoS Mitigation Solution OverviewDoS Mitigation Solution Overview

Untrusted

DPPM sipd

Trusted

SIPSIP SIP

RTP RTP

Filter I Filter II

VoIP Traffic

Attack Traffic

Untrusted

DPPM sipd

Trusted

SIPSIP SIP

RTP RTP

Filter I Filter II


Hardware PlatformHardware Platform

10/100/1000 10/100

E1E2

Backplane

F0

C3

C4

Gigabit Ethernet Interconnects

D0

D1

E1E2

F0

C3

C4

D0

D1

3 4

P0

P0

System Level Port DistributionSystem Level Port Distribution

Application Server ModulePentium 1GHz

1000 1000

0 1 2

ASM

DPPM

Intel IXP 2800

DPPM

Intel IXP 2800


Integrated DDOS and Dynamic Pinhole FilterIntegrated DDOS and Dynamic Pinhole Filter

DPPM

Inbound Outbound

SIP

Linux server

Switch

FCP/UDP

Drop

Lookup

CAM CAM

DynamicTable

StaticTable

CAM CAM SIPDDOS

DDOSTable

CAM CAM

ASMsipd


Integrated Testing and Analysis EnvironmentIntegrated Testing and Analysis Environment

GigE Switch GigE Switch

SIP Proxy

Call Handlers

SIPUA/SIPp

Controller secureSIP

AttackLoaders

SIPStone/SIPp

Legitimate Loaders

SIPUA/SIPp

Firewall


Theft of Service OverviewTheft 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


The Bigger Picture - Columbia VoIP TestbedThe 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


Intellectual Property – Six Patent ApplicationsIntellectual 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)


External – Publications, Presentations, RecognitionExternal – Publications, Presentations, Recognition

• Presentation at NANOG 38 – Oct. 10 2006 (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 38 2006 Proceedings– Made a headline in VON Magazine on October 11, 2006:

http://www.vonmag.com/webexclusives/2006/10/10_NANOG_Talks_Securing_SIP.asp

• Presentation to at Global 3G Evolution Forum – Tokyo, Japan, Jan. 2007 (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 4995-1: Special Topics in Computer : VoIP Security (HS)

• CATT Technological Impact Award - 2007


Recommended Next StepsRecommended 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?


ConclusionsConclusions

• 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


Thank YouThank you

Questions?


Backup Slides…Backup Slides…


SIP Security OverviewSIP 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


SIP Security Overview - 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


Dynamic Pinhole Filtering Dynamic Pinhole Filtering

SIP/2.0 200 OKFrom: <sip:user1@handler>

c=IN IP4 128.59.19.162m=audio 56432 RTP/AVP 0

INVITE sip:[email protected]

From: <sip:user2@loader>c=IN IP4 128.59.19.163m=audio 43564 RTP/AVP 0

CAM Table

SIPUAUser2

SIPUAUser1

128.59.19.163:43564

128.59.19.163:56432


SIP DoS and ToS Attack TaxonomySIP DoS and ToS Attack Taxonomy

• DoS– Implementation flaws

– Application level

– Flooding

• ToS– Billing Threats

– Authorization Threats

– Service Threats


Strategy FocusStrategy 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


SIP Detection and Mitigation FiltersSIP 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


Test ToolsTest 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


secureSIP Control ArchitecturesecureSIP Control Architecture


secureSIP Test Results for DoSsecureSIP Test Results for DoS

Firewall Filters OFF Firewall Filters ON

Traffic Composition

Good

CPS

Attack

CPS

CPU

Load

Good

CPS

Attack

CPS

CPU

Load

Non-Auth Traffic 690 0 87.81 690 0 88.04

Auth Good Traffic

240 0 19.83 240 0 39.64

480 0 81.20 480 0 81.75

Auth Good Traffic +

Spoof Traffic

240 2950 83.64 240 16800 41.39

480 195 85.40 480 14400 82.72

Auth Good Traffic +

Flood of Requests

240 3230 84.42 240 8400 40.83

480 570 86.12 480 7200 82.58

Auth Good Traffic +

Flood of Responses

240 2970 87.2 240 8400 41.33

480 330 86.97 480 7200 82.58

Auth Good Traffic +

Flood of Out-of-State

240 2805 86.24 240 8400 40.29

480 290 84.81 480 7200 82.19

Concurrent

Calls

Call rate

(CPS)

Delay due to Firewall

Pinhole opening Pinhole closing

20000 300 0.73 0

25000 300 0.75 0

30000 300 0.83 15.51

30000 200 0.80 0.02

SIP DoS MeasurementsSIP DoS Measurements(showing max supported (showing max supported

call rates)call rates)Dynamic PinholeDynamic Pinhole

sipcolumbiasymposium

Documents

voip theft of service

voip security evaluations

enhanced voip security

verizon security architecture

service integrity

verizon vendors

sipbased voip systems

voip security alliance