From en.secnews.gr
Last year, one malicious campaign has put in risk telephone systems VoIP (Voice over Internet Protocol) more than 1.000 companies worldwide.
Although the main purpose of this attack is to sell phone numbers and call plans that others can use for free, access to VoIP systems could enable criminals to carry out more attacks, including listening to private calls, of cryptomining or even the use of compromised systems as a starting point for very serious attacks.