DDoS (Distributed Denial of Service) may be getting all the recent press, but now the FBI, Homeland Security and several more federal agencies have issued a no-nonsense warning about a spike in the number of TDoS (telephony denial of service) attacks which wipe out a victim's telephone service.

The focus of the warning was a jump in TDoS against public sector emergency services agencies (police, ambulance, etc.) The warning noted: “The perpetrators of the attack have launched high volume of calls against the target network, tying up the system from receiving legitimate calls. … Many similar attacks have occurred targeting various businesses and public entities, including the financial sector” (emphasis added).

The scariest part: security researchers talk about TDoS kits that can be rented for as little as $20 per hour. And that service will generate ample junk calls to put your credit union's telephone system down for the count.