IntroductionWhat Is IP TelephonyVoIP PhoneWorking of VoIPProtocols in IP Telephony
IP TelephonyIP telephony is a technology in which IPnetworks are being used as the mediumto transmit voice traffic.Voice over IP (VoIP) Describes an IP telephony deployment where the IP network used as the medium to transmit voice traffic is a managed IP network.Voice on the Net (VON) Describes an IP telephony deployment where the IP network used as the medium to transmit voice traffic is the Internet.
Working of VoIP PhoneVoIP Phone Requires broadband internet access and regular house phones which plug into an analog telephone adapter (ATA).Working of VoIP works by the two-way transmission of voice over a packet-switched IP network Equipments VoIP phone call server gateway.
Protocols in IP TelephonySignaling protocols perform session management and are responsible for Locating a user Session establishment Session setup negotiation Modifying a session Tearing down a session
VulnerabilitiesConfidentiality Refers to the protection of data from being read by an unauthorized user.Integrity Includes the unauthorized modification or deletion of voice/data content.Availability Storage and transportation facilities for an information system are accessible to authorized users
ConfidentialityData Link Layer Address Resolution ProtocolNetwork Layer Address Spoofing Identifying IP Address of the PhoneTransport Layer Real Time ProtocolApplication Layer MAC Address Spoofing
AvailabilityBandwidth consumption Comprise of flooding the network with a specific type of traffic.Resource Starvation attacks Flood a device (opposed to links in a bandwidth consumption attack).Routing Attacks Involve manipulating routing information or protocols in order to intercept / interrupt legitimate traffic.Programming Flaws Unintended bugs in software that can be exploited by other user in order to gain access to a system .
VoIP Security ToolsVoIP systems become more prevalent and risk grows,network engineers need to make sure the properprecautions are taken to prevent security breaches. Some testing tools SiVuS c07-sip
SiVuSFirst publicly available vulnerability scanner for VoIP networks.SIP Message generator Used to test issues or generate demonstration attacksSIP component discovery Useful for identifying targets for analysis.SIP vulnerability scanner Used to verify the robustness and security of SIP phones, proxy servers and registrar servers .
Strengths Windows-based GUI design Reports are generated in an easy to read html page Checks both the robustness and the presence of security features
WeaknessesLack of informationSIP device failed to locate the Asterisk serverIssues arose on required SiVuS to be restarted.authentication were found to report inaccurate results.Running the test cases repeatedly fails to find a target on the first attempt
ConclusionNone of the security tools evaluated were significantly effective for mitigating security risks in SIP-based VoIP networksEarly stages of adoption, attacks have been either largely unheard of or undetectedParticularly important to prevent DoS attacksAll tools today are still under heavy development and will no doubt evolve as VoIP adoption increasesVoIP specific security tools should play an important role in securing systems.
References B. Charney, "VoIP threats must be dealt with now,“ CNET News.com, 8 Feb. 2005; J. E. Canavan, Fundamentals of Network Security, Boston: Artech House, 2001 L.N.Vikram,Web Design And Multimedia Applications 4th Edition, Pearson Educations Sikinder S.R.R.C, Voice On Internet Protocol A Basic Approach, Charles House,2007 www.wikipedia.org.in www.google.com Digit magazine