Henning Schulzrinne Columbia University VoIP Security Henning Schulzrinne Columbia University November 2006 VoIPSec

Overview Taxonomy General network threats made worse Resources November 2006 VoIPSec

Services Call control Directory services Gateway service call establishment, reporting, mid-call service features, and teardown  SIP, proxies Directory services alias, user name, extension, E.164 number  URL (ENUM) Gateway service inter-work between two different types of networks, e.g., PSTN and VoIP  media gateways Network services DNS, TFTP, FTP, DHCP, HTTP, Telnet, RADIUS, and DIAMETER Session border control functions signaling and/or bearer traffic as it crosses a trust boundary November 2006 VoIPSec VoIPSA report

Multi-party freedom model People can move from role to role: Initiating contact Joining communication in progress Accepting contact Terminating communication in progress Refusing contact November 2006 VoIPSec

VoIP threat taxonomy November 2006 VoIPSec

User requirements and goals User is able to … … invite anyone … to join multiple parties … refuse an invite … drop out of a session … indicate consent for any and all contact and reporting … refuse consent for any and all contact and reporting … set policies for the user and all legally subordinate domains user is assured confidentiality and immunity for lawful communication November 2006 VoIPSec

Privacy and security The Privacy Concept = privilege of all people to have their communication systems and content free from unauthorized access, interruption, delay or modification consent of the person claiming privacy within the limits of the law Security = the right to protect privacy, a method of achieving privacy ways to keep communication systems and content free from unauthorized access, interruption, delay or modification November 2006 VoIPSec

Social threats: Misrepresentation Misrepresentation includes the delivery of information which is false as to the identity, authority or rights of another party or false as to the content of information communicated identity authority (false authentication) rights (false authorization) content (audio, video, text) Examples: false caller ID, organization, name voice masking and impersonation false presence information “phishing”, “vishing” social engineering (see ChoicePoint) false claim of government authority November 2006 VoIPSec

Social threats: Theft of services Theft of services is any unlawful taking of an economic benefit of a service provider by means intended to deprive the provider of lawful revenue or property. unauthorized deletion or altering of billing records unauthorized bypass of lawful billing systems unauthorized billing taking of service provider property Common in PSTN e.g., resale of services with delayed billing “blue boxes” November 2006 VoIPSec

Social threats: unwanted contact Unwanted contact is any contact that either bypasses prior affirmative consent (opt-in) or a refusal of consent (opt-out) Can be illegal (harassment, extortion, fraud) or just unwanted Harassment “Harassment is any form of unwanted communication which embarrasses, intimidates, vexes, annoys or threatens the receiver of the communication with actions which are improper under the law.” Extortion “Extortion is any act to induce another to do or refrain from any conduct or give up any freedom, right, benefit or property, under a threat of loss or harm to the person, their reputation, property or the health, safety, reputation or welfare of anyone they know.” November 2006 VoIPSec

Resources Security consideration sections in RFCs http://www.voipsa.org November 2006 VoIPSec