Hackers are using VoIP to launch DDoS attacks against hospital ER's and 911 call centers. The hackers are then demanding hundreds of dollars in ransom money to stop the attack. Similar to other ransom scams, this scam is harnessing hapless computers to force thousands of compromised computers to overwhelm the target computers.

What worries security providers is that, although it has not reached a national security level yet, it well could be. Hackers could use this attack to knock out crucial infrastructure such as hospitals and 911 call centers.

Since mid-February, the Internet Crime Complaint Center, a task force that includes the FBI, has received more than 100 reports about telephony DDoS attacks. Victims have paid $500 to $5,000 to bring an end to the attacks.

The hospital attack was eventually ended using a computer firewall filter. However, most firewall filters target specific telephone numbers and the attackers can delete and create new one instantly.