Why spam calls come from similar numbers to your phone number
mobile spam · 7 comments · 250 words · Viewed ~476 times.
In the last few months, I've received dozens of spam calls which appear to come from a similar phone number to mine.
If my number is 07700 900 123 I get calls from 07700 900 124 or 07700 900 456
Here's my working theory on why spammers do this. Americans.
In the UK, there's a separate "area code" for mobile phones. If a number starts 07 then it is mobile (it's a bit more complicated than that).
In the USA, there's no cellular prefix. If you buy a SIM card in Las Vegas, you'll probably get a 702 number - at least, I did when I last visited.
Some of the area codes in the USA cover tiny geographic areas.
Spammers know this. They bet that if they call +1-555-867-5309 from +1-555-867-5409 the person will believe the spammer is local to them. Possibly even a neighbour. It is a weak form of social engineering attack. You're more likely to trust someone local than a distant stranger.
In the UK this doesn't work. Not because we don't trust our neighbours, but because our mobile numbers aren't tied to a specific geography.
Cultural hegemony can be an effective anti-shibboleth!
Michael S says: