VOIP could be subject to DoS and SPAM
According to an article on internet.com denial of Service (DoS) attacks against VoIP networks are a real possibility, and there's even a distant risk of spam over Internet telephony, or SPIT.
The problem lies with Microsoft's adoption of Session Initiation Protocol (SIP), a signaling protocol for Web conferencing, telephony, presence, events notification and instant messaging.
The possibility exists that once you're in a SIP environment you may become vulnerable to the vulnerabilities of the public Internet.
In January 2003, CERT warned SIP was vulnerable to remote code execution and other cracks, while the U.K. National Infrastructure Security Co-Ordination Centre advised early this year that the H.323 networking protocol for transmitting audio-visual data supported by many VoIP networks put them at risk for DoS and buffer overflow attacks.
