In UK some of the call centres use a fake local number.

It seems to me that phone companies can detect that, but they don't want to reduce the number of calls, do they?

How is a spammer going to figure out phone numbers of people on my list from social media? I don't know about you, but I don't have my Facebook friends publicly viewable.

And that's an awful lot of work just to cold-call someone to try to sell them insurance or whatever.

With a handy-dandy facebook bug that allows them to scrape such data at scale?

This has happened multiple times before, at least two separate incidents have made the news.

This doesn't seem like a reliable way of running a business: just hoping that you can exploit a bug in Facebook (which will surely be fixed before long) so you can grab people's friends, try to figure out their phone numbers, then spoof them, then cold-call them trying to sell them crap insurance.

I'm sorry, this just sounds far-fetched to me. History seems to have shown that when hurdles are just a little too high, the spammers just don't bother.

Why just facebook? Spammers have been exploiting bugs like this in everything for years. The data gets scraped and then sold and resold.

This would need to be spoofed for every individual though. I imagine this would be cost prohibitive enough that it would at least in the short term kill most spam phone calls.

On the contrary, it represents a revenue opportunity for the first person who can generate a list of matching pairs of phone number and friend phone number. I wouldn't expect the list to be prohibitively expensive because it will be resold thousands of time.

Can you explain phone number spoofing to me? Is there truly phone spoofing that is more than faking the dialer on the client?

There is no way for you to verify whether the caller's phone number is actually the real source. Anyone can impersonate anyone. It's like the source address in an IP packet. You can put whatever you want in there.

This is mostly a US problem though. In Europe, the operators tend to be more strict on this, AFAIK.

You should read the book "Ghost in the Wires" by Kevin Mitnick. It will really open your eyes as to what is possible with phones.

can I borrow your copy? I will pay shipping to and fro' :)

Sure! But honestly, it will probably be cheaper for you to just buy it from Amazon for $8. Or, read it for free using Overdrive (if you have a Kindle/ereader).

But this way I get to bug you about my discoveries and compare interpretations with yours... the knowledge comes with instruction hehe