A DoS attack aims to overload your VoIP network and disrupt the normal functioning of VoIP telephony services. One way this is achieved is through call flooding. Cybercriminals will send numerous calls your way that, when answered, cause the phone lines to ring almost immediately. Such actions can severely disrupt your business and cause chaos across the organisational supply chain.

This is a hacking activity where a computer system is used to dial numerous phone numbers to find devices that display a weak or poorly secured access point. If you have such vulnerabilities, the hacker will attempt to enter your network.

When there is unencrypted Session Initiation Protocol (SIP) traffic, a hacker can intercept the VoIP calls - including video calls. Someone who manages to intercept your VoIP phone system can collect phone numbers, passwords and account names.

This type of fraud uses radio frequencies to infiltrate your VoIP system. They connect their external phone line to your network and can change your account details, make long-distance calls, and add and remove account credits. Phreaking increases your VoIP costs and gives hackers access to your voicemail and billing services.

Spamming over Internet Telephony is the phone version of spamming. Hackers of the IP address associated with your VoIP account will be able to send their own voicemail messages to thousands of voicemails. It results in an overloaded voicemail management system and carries the risk of viruses and spyware attached to voicemails.

Attackers who implement this breach get access to your phone system and make expensive international numbers. They usually call premium phone numbers to receive a portion of the money charged from these calls —leaving you with a high phone bill.