Voip

Voice over Internet Protocol

Collaborative Research

Protect your VoIP network

BY

Karthik

Security is important in every context, but especially when you're replacing the world's oldest, largest and most resilient and available communications network. While no individual security measure will eliminate attacks against VoIP deployments entirely, a layered approach can meaningfully reduce the probability that attacks will succeed.

The threats

Enterprise VoIP customers and service providers are vulnerable to many of the same impersonation-based attacks "phreakers" attempt against traditional telephone and cellular services. The goals - identity and information theft and toll fraud - are the same.

Many attacks focus on VoIP endpoints. The operating systems, Internet protocols, applications and management interfaces of VoIP hard phones and computers running softphones are vulnerable to unauthorized access, viruses and worms, and many denial-of-service (DoS) attacks that exploit common Internet protocols and VoIP protocols themselves.

VoIP uses the IETF Session Initiation Protocol (SIP) and the Real-time Transport Protocol (RTP) for call signaling and voice-message delivery. These and complementing session description and RTP control protocols (SDP, RTCP) do not provide adequate call-party authentication, end-to-end integrity protection and confidentiality measures on call signaling and call data (such as media streams containing compressed and encoded speech). Until these security features are implemented and put into service, attackers have many vectors to exploit.

Security VoIP graphic

Today, SIP and RTP protocols do not encrypt call-signaling packets and voice streams, so identities, credentials and SIP Uniform Resource Identifiers (phone numbers) of callers can be captured using LAN and wireless LAN (WLAN) traffic-collection tools (sniffers).

An attacker can use captured account...