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Ask HN: How can scam callers fake a mobile phone number?

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Re: Ask HN: How can scam callers fake a mobile phone number?

#81

Post by ceejayoz »

xwdv wrote: post #70
ceejayoz wrote: post #48

Earlier quoted context omitted.

> No, that's the public portion of a social security number. It really isn't.

It is, and you must set aside your personal feelings and treat it as public info. If people think these digits are like some secret password, they will be treated as such and used to gatekeep access to even more restricted info and accounts. Which would be a disaster because many people have had these last four digits exposed over time. Knowing them does not prove identity. They are public.

Like it or not, many banks and other industries use it as a verification question. A collections agent is going to be explicitly and strictly forbidden by policy from disclosing it to an unknown person on the phone, and that's a good thing.

Yes, I'm pretty sure everyone has my SSN and other details, but collections agents should absolutely follow the rules. The ones that don't tend to be abusive.

Re: Ask HN: How can scam callers fake a mobile phone number?

#82

Post by thesis »

lowlevel wrote: post #35
jaywalk wrote: post #26

Earlier quoted context omitted.

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.

This is what I do, and feel is the only solution now. Phone always on DND/only allow contacts to ring. A whitelist approach if you will.

This is great and all until there’s an emergency and someone is trying to reach you.

Re: Ask HN: How can scam callers fake a mobile phone number?

#83

Post by b3morales »

edmundsauto wrote: post #67
soco wrote: post #47

Earlier quoted context omitted.

Yet another example of the often discussed "Google search results infestation"...

Also possible if they gave malware on the computer, and it modifies search results in the browser. That’s always seemed like a serious vector although I haven’t heard much in the way of in the wild exploits.

Computer malware + phone scam sounds like a remarkably targeted, technically broad, and labor intensive attack.

Re: Ask HN: How can scam callers fake a mobile phone number?

#85

Post by fxtentacle »

deadcore wrote: post #28

The 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 c…

Thank you for this rabbit hole. Today I learned a lot about modulation, frequencies, and how DSL works :)

In the end, the most surprising snippet of knowledge for me was that Erlang (that Amazon S3 is built in) was invented by Ericsson for live patching ISDN phone routing systems without dropping any ongoing call.

Re: Ask HN: How can scam callers fake a mobile phone number?

#86

Post by fxtentacle »

mef wrote: post #38
ghostpepper wrote: post #30

I 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 you…

on iOS, the "Silence Unknown Callers" feature has completely eliminated this for me.

I was actually waiting on a call back from a parcel company, so the scam caller in this case just had very lucky timing.

Re: Ask HN: How can scam callers fake a mobile phone number?

#87

Post by mrozbarry »

One thing people don't know is that the phone network is actually a bunch of duct-taped technology that is pretty old. There has been advancements, and if you're in the US, you'll be happy to know that mobile carriers require stir/shaken handshaking, which is _mostly_ equivalent to https on the web (this is a gross simplification).

The short/simple answer is carriers don't care, because they make money when a call is placed on their network. There is also a difference between what is a valid number (digits are correct) vs a real number (someone owns a number). It is cheap for a carrier to check validity, but not "realness" - to check a real number, a carrier may have to do some sort of data request to any number of carriers to determine if the number is owned.

Re: Ask HN: How can scam callers fake a mobile phone number?

#88

Post by toast0 »

litgab wrote: post #72

I just got a call from the Microsoft Security Team. They informed me my computer was highly infected. I spent 1 hour with them executing all cmd commands they wanted & told them the output. In the end i told them my wifi was broken and the technician should come by soon to fix it. She turned very aggressive and told me to call my brother Internet provider right now, as this is urgent because the hackers are already i…

> I just got a call from the Microsoft Security Team.

They used to call be, but they said they were from 'The Windows'. I tried to get them to play Zork, but they weren't very interested, and it took me a little too long to get it started anyway.

Re: Ask HN: How can scam callers fake a mobile phone number?

#89

Post by throwawayboise »

bombcar wrote: post #10
toast0 wrote: post #5

> - How can a spam caller call me with a source phone number that does not exist? The same way they make a call with any source number. The two source numbers in a call (ANI and CallerID which don't need to be the same) have historically been not required and not validated. See stir/shaken for a modern effort to change this. Coming soon to a carrier near you; maybe. Being able to set the source number enables many us…

To go further on this, the T1/DID allows you to set various numbers for the outgoing (for example, so that all calls from your company appear as "main company number", or all calls from support people come from the "support number"). The CallerID is very easy to replace with anything, but even the ANI can be replaced, and until recently, nobody verified anything at all. And lots of "back end" things depend on this si…

Yeah when I was on Republic Wireless I'd sometimes get calls from people who had called the "secret" number because it had been recycled. I used to get calls from the county clerk's office reminding me of my upcoming court dates and probation appointments. I called them back and said you must have a wrong number, they checked and of course had no record of my phone number on any of their records and could not understand why I was getting these calls, nor could they figure out who should have been getting them. Later I realized that someone must have had that "secret" number recently and it had been recycled into Republic's pool.

Re: Ask HN: How can scam callers fake a mobile phone number?

#90

Post by fxtentacle »

notreallyserio wrote: post #39

I wish phone calls came with a verified (cryptographically) description of the route a call took to get to me. Then I could use a library/app to filter by source or by bad actor (providers that lie about the route). That would enable services like UBlock Origin, allowing for user-generated blocklists.

Great idea!

Local area number but traceroute to a call center in India? Automatically reject.

That'll also solve the issue of unusable corporate phone support because they outsourced it to save a few bucks.

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