Security Issues and Countermeasure for VoIP

........................................................................................................... 4 Document Conventions................................................................................... 4 Introduction.................................................................................................... 5 Overview of VoIP techniques.................................................................... 6 VoIP components.......................................................................................... 6 VoIP Data handling ................................................................................... 8 Quality of Service for VoIP ................................................................ 9 VoIP protocols.......................................................................................... 11 H.323 protocol ...................................................................................... 12 Session Initiation Protocol (SIP).............................................. 14 MGCP and Megaco/H.248 ....................................................................... 15 Security threats of VoIP ........................................................................ 16 Confidentiality threats....................................................................... 16 Eavesdropping of phone conversation ......................................... 16 Unauthorized access attack............................................................. 16 Countermeasures .................................................................................... 17 Integrity Threats ................................................................................... 17 Caller Identification spoofing .................................................... 18 Registration hijacking ..................................................................... 19 Proxy Impersonation............................................................................ 20 Call redirection or hijacking ...................................................... 20 Countermeasures .................................................................................... 22 Availability threats ............................................................................. 23 VoIP Signaling DoS Attacks............................................................. 23 VoIP Media DoS Attacks ..................................................................... 23 Physical DoS Attacks ......................................................................... 24 Countermeasures .................................................................................... 24 Firewall and Network Address Translation challenges........... 25 Security Guidelines for VoIP ............................................................... 27 Conclusion ...................................................................................................... 29 References ...................................................................................................... 30