A hacking campaign has compromised VoIP (Voice over Internet Protocol) phone systems at over 1,000 companies around the world over the past year in a campaign designed to make profit from selling compromised accounts.
While the main purpose appears to be dialling premium rate numbers owned by attackers or selling phone numbers and call plans that others can use for free, access to VoIP systems could provide cyber criminals with the ability to conduct other attacks, including listening to private calls, cryptomining, or even using compromised systems as a stepping stone towards much more intrusive campaigns.