Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/08/robocall_result.html
A group of researchers set up a telephony honeypot and tracked robocall behavior:
NCSU researchers said they ran 66,606 telephone lines between March 2019 and January 2020, during which time they said to have received 1,481,201 unsolicited calls — even if they never made their phone numbers public via any source.
The research team said they usually received an unsolicited call every 8.42 days, but most of the robocall traffic came in sudden surges they called “storms” that happened at regular intervals, suggesting that robocallers operated using a tactic of short-burst and well-organized campaigns.
In total, the NCSU team said it tracked 650 storms over 11 months, with most storms being of the same size.