I saw this kind of fraud last year, we are a small carrier in Mexico city, the attackers send a burst of calls to one of our customer's 1-800 number, we realized by the huge amount of calls with really short duration -10 seconds at most- and it caused our customer was out of service temporarily as the PBX was exhausted. The attack came from an specific number from another local carrier, although it was identified the user was a PBX extension and allegedly abused by hackers hence no direct responsible identified. We block the originating number to prevent much more calls were completed. From: VoiceOps [mailto:voiceops-bounces at voiceops.org] On Behalf Of Geoffrey Mina Sent: jueves, 03 de abril de 2014 10:01 a.m. To: VoiceOps Subject: [VoiceOps] Toll-Free Fraud/Spam We are seeing a relatively high number of strange calls hitting a portion of our Toll-Free numbers. The ANIs are mostly disconnected/invalid. When our system answers, we hear silence, a DTMF tone, and then a fast busy on the inbound RTP stream. We are seeing this over multiple TF vendors. Is anyone else seeing anything like this out in the wild? Thanks, Geoff AVISO DE CONFIDENCIALIDAD: Este correo electr?nico y sus archivos anexos, si los tiene, est?n destinados s?lo para la persona o entidad a la que va dirigida y contiene informaci?n confidencial. Se proh?be cualquier uso, impresi?n, divulgaci?n o distribuci?n de dicha informaci?n sin la autorizaci?n por escrito del remitente. Si usted no es el destinatario, por favor p?ngase en contacto con el remitente y destruya todas las copias del mensaje original. CONFIDENTIALITY NOTICE: This email message and its attachments, if any, are intended only for the person or entity to which it is addressed and contains privileged information. Any use, printing, disclosure, or distribution of such information without the written authorization of the sender is prohibited. If you are not the intended recipient, please contact the sender and destroy all copies of the original message. Nuestro aviso de privacidad est? publicado en la p?gina Web: http://www.mcmtelecom.com.mx/common/politica_privacidad.htm