Researchers received 1.5 million calls to numbers no one knew

[Tomcat]

Experts from North Carolina State University presented an interesting talk at the USENIX conference and talked about their experiment, which was devoted to auto-dialing.

To conduct the experiment, the researchers created a huge telephone honeypot and operated 66,606 telephone lines for 11 months (from March 2019 to January 2020). In total, during this time, scientists received 1,481,201 unsolicited robotic calls. Moreover, honeypot phone numbers have never been publicly available.

On average, unsolicited calls were received every 8.42 days, and most of the robocalls came in peculiar waves, which experts called "storms." These bursts occurred regularly, at regular intervals, and it seems that these calls were made as part of well-organized campaigns. For 11 months, experts have recorded 650 such "storms".

Interestingly, not all calls during such bursts of activity came from robots: most of the callers turned out to be real people. Experts speculate that the caller ID spoofing tactic is to blame, that is, dialers tend to hide their real phone numbers and impersonate real people. Thus, when victims missed a robocall and later called back a fake number, they ended up on the honeypot numbers of the research team.

“Interestingly, our laboratory colleague also fell victim to such a storm. Hundreds of strangers literally inundated him with calls, and they complained that they were called from his number! Needless to say, he could not use the phone for several days until the calls died down, ”the experts say.

The team of scientists recorded approximately 10% (about 150,000) of the received robocalls, which were then analyzed to determine their source and content. This identified 2,687 unique auto-dialing campaigns, the largest of which advertised student loans, health insurance, Google search engine promotion, and social security scams.

But perhaps the most interesting conclusion from the experts' experiment was the following: after answering one and a half million robotic calls, the researchers did not notice any increase in the number of such calls in general.

“The media and regulators are constantly advising users to avoid calls from unknown numbers in order to reduce the number of calls from robots. Surprisingly, we found that answering such calls does not necessarily increase the future number of robocalls. Users should be careful when calling from unknown numbers, but if you answer an unsolicited call from time to time, this does not mean that in the future you will receive many more calls from robots, ”the authors of the experiment summarize.