A spike in attacks against IP PBXs that started last fall shows no signs of abating. Speculation that those responsible have tapped into botnets and cloud computing resources. The most common exploit against compromised PBX is toll fraud – using someone else’s phone system to make long-distance calls. The top three attack-launching locations are China, Russia and the U.S., Sipera’s Viper Lab research arm says. The scale of attacks at any given moment indicates that botnets might be in play, but there is no hard evidence that either they or cloud resources are involved.”]