Threats Against Availability

Threats against availability are actually a group of threats against service availability that is supposed to be running 24/7 (24 hours, 7 days a week). That is, these threats aim at VoIP service interruption, typically in the form of Denial of Service (DoS).

The typical threats against availability are as follows:

• Call flooding

• Malformed messages (protocol fuzzing)

• Spoofed messages (call teardown, toll fraud)

• Call hijacking (registration or media session hijacking)

• Server impersonating

• Quality of Service (QoS) abuse

The following subsections describe the threats with examples, which show you how they impact service availability.