Being able to set outbound Caller ID is something that is common with SIP providers and T1/PRI providers. The most common case today is using SIP. The billing happens at the provider level, and is not based on the user defined Caller ID field. Anyone can setup an Asterisk instance and make the caller ID value on the outgoing calls whatever they want [1].
Ask HN: How can scam callers fake a mobile phone number?
21–30 of 156 posts
Re: Ask HN: How can scam callers fake a mobile phone number?
#22[deleted]
Re: Ask HN: How can scam callers fake a mobile phone number?
#23I think a much better question is, why can scammers spoof a phone number? We hear lots of excuses from the carriers about how this is out of their control, this is how the system works, etc. Why don't they feel like they have a fire lit under their asses to fix the issue? My immediate guess is that they must make money off of scam calls somehow. A scam call is still a call.
Yeah, and the net effect is that they're shooting themselves on the foot: I don't even pick up phone calls anymore. And I don't think I'm alone in this: most families and friends claim only to answer calls of close contacts. Legitimate services nowadays just contact you in WhatsApp instead.
Re: Ask HN: How can scam callers fake a mobile phone number?
#24Hoping this is something that doesn't need to be said here, but just in case: This is why you should NEVER provide personal information over the phone if you didn't initiate the call. It doesn't matter if your caller ID says it's your doctor's office or your bank or whatever. Hang up and call them back at the number you normally use to reach them, from their website or the back of your credit/debit card for example.…
I remember many years ago getting a random phone call from someone who claimed they were a detective investigating a case. The detective sensed my skepticism right away over the phone and suggested that I look up the phone number for his police department, and to ask for badge number ZZZ when I call. I called back, everything was above board, they came and interviewed me (they wanted to see if I still had something in my possession which I thankfully did), they made a mark on the item to indicate that they had seen it already and I never heard from them again. Though I wonder if they ever caught whoever it was that was using that item ...
Re: Ask HN: How can scam callers fake a mobile phone number?
#25This is why I like having my number from where I lived in 2005 (see https://xkcd.com/1129/ ) - any calls from "my area code" are automatically spam unless it is a particular number I know.
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Re: Ask HN: How can scam callers fake a mobile phone number?
#26Earlier quoted context omitted.
The problem is that carriers (especially smaller ones) have been dragging their feet on implementing it, and nobody can use it to actually block calls until essentially everybody supports it and is interoperating. Until then, phones will just show calls between STIR/SHAKEN carriers as having verified caller ID.
would it be possible to tell my carrier to simply block all call that are not (STIR/SHAKEN)? If all my friend are on carrier that support it, I am not interested in receiving call from people that are not on a carrier that support it.
I highly doubt any carrier would offer this, especially with the current adoption being where it's at. You'd be better off using your phone's capabilities to restrict calls to only your contacts.
Re: Ask HN: How can scam callers fake a mobile phone number?
#27Because carriers are arcane companies that have a monopoly on a swath of infrastructure and have little care or perspective on what products and consumer experience amounts to.
They buy and install equipment and sell out the voice/data.
They actively oppose, thwart any kind of thoughtful innovation, competition etc. on anything relating to their networks, because they believe they 'own' the network and therefore 'own' everything going on on top of it.
Remember the 10-cent 'WAP' pages? Tiny, crappy, useless little mobile web pages? And they wanted 10-cents each?
Carriers would originally not sell BlackBerry service. They thought it was stupid to have 'email' on their networks. BlackBerry had to buy data and then sell to the C-suite.
Then, BlackBerry literally became the reason that people wanted to buy data. The carriers then said - you can't buy network and resell it, you must sell your products through us.
Imagine if some private companies controlled all of the roads. Any and business wanting to put a car on the road had to pay a toll, and the owners could decide which kinds of cars, when, and for what reason and intervene. They tried to provide the ambulance and transport for everyone and keep messing it up.
It's also an artefact of human organization, even a fairly enlightened community/government body would have difficulty setting clear and appropriate guidance.
The issue becomes problematic when there is a control of a scarce resource.
In truth, it's absurd that people should be able to easily fake 'from' numbers, we should have fixed that a decade ago.
Re: Ask HN: How can scam callers fake a mobile phone number?
#28The how - depending on the protocol.
Signalling System No. 7 - ISDN User Part spec (found here: https://www.itu.int/rec/T-REC-Q.763-199912-I/en) allows you to specify both a calling party number (3.10) and generic number (3.26) (the UK spec adds an additional presentation number so you have 3). This will typically require the help of an operator which is 'connected' to the network on the PSTN. A real business case can be made; like a generic, non geo support numbers appearing on the persons phone instead of the geographical number of the office which called. Either a bit of social engineering or findings a less scrupulous operator is all you really need to do
SIP has FROM and P-Asserted-Identity headers which follow the same process
Re: Ask HN: How can scam callers fake a mobile phone number?
#29This is why I like having my number from where I lived in 2005 (see https://xkcd.com/1129/ ) - any calls from "my area code" are automatically spam unless it is a particular number I know.
This is the same thing for me. Short version is that I'm from Detroit area, lived in NH for a while, and now reside in Tampa area. My cellphone has a 603 area code (NH). But since I'm not from there, the only 603 numbers I care about are already in my address book, any others are guaranteed to be spam calls. This lets me easily ignore 95% of them (I also occasionally see an 802 (VT) number or a 978 (MA) number).
What is interesting is that I have started to receive more 727 (local area code) spam calls, maybe 2-3 per month. I suspect this must be from local friends and contacts leaking my number through sharing address books with various apps.
I am at the point now where incoming phone calls are near valueless, other than from a very small set of numbers. Most people text me, or contact me through other apps/methods. Even for business purposes, incoming calls are almost always scheduled and the very very few that are not, and from an unrecognized number, can leave a voicemail.
It is somewhat amazing how the telco's have let their core product, voice calls, become nearly worthless by not handling these spam call problems. Now I'm using contact methods and apps that are not provided by telcos and not strictly reliant on their networks.
Re: Ask HN: How can scam callers fake a mobile phone number?
#30I live in Canada, and I and most people I know receive spam calls from spoofed numbers on a semi-regular basis.
Sometimes the number only a few digits off from my number, but other times it has a name like TOLL FREE SERV. A common lure is claiming they are Service Canada or Canada Revenue Agency (or the nonexistent Revenue Canada), and the call will open with nonsensical threats like “A warrant has been placed in your social insurance number”. I have a hunch they often target wealthy international students, as sometimes the messages are entirely in Chinese.
Recently I received three calls in one day. It’s been happening for years, and the phone companies don’t appear to be able/willing/motivated to stop it. Most people I know have just resorted to not picking up calls from unknown numbers.