Ask HN: How do I prevent my phone number from leaking via LinkedIn?

2 points by calrueb 4 years ago | 1 comment

Sometimes when I am bored I like to pick up unknown caller/spam calls just to see what they are peddling, and this morning I was in one of those moods. However, when I answered I was surprised to hear a real person on the other end of the line that knew my name, my employer, and my role. They were trying to sell me on their startup product which is aimed at people in my position.

I was quite surprised how he had all this information on me, and I asked where he got my phone number thinking perhaps we have a mutual connection that put us in touch. Instead, he said he found me and my phone number on LinkedIn. We had a bit of back-and-forth, and I politely ended the call.

I have double checked, and there is no phone number connected to my LinkedIn account. Instead, I suspect this seller has some sort of Chrome extension which is adding extra contact info metadata to public LinkedIn profiles. With that, a seller can look for people with my job title, and then use that contact info to do cold outreach.

Is that likely what happened in this case, or is there another avenue I am not considering? How might I prevent these creepy calls in the future? I suspect if there are 1-2 large players who offer this service I could ask them to delete my data. I don't want to delete my LinkedIn account over this as I have found it relatively handy.

curph 4 years ago |

For the technically inclined, try a partitioning strategy that involves multiple phone numbers. Cost: Asterisk server on Digital Ocean (or competitor) plus a very low monthly rate and per minute rates.

1. One can acquire US phone numbers for anywhere from as low as $0.06 per month, in the area code of your choice.

2. Acquire several numbers (several dozen, perhaps) and when you are using any services on the Internet that require a phone number, share an appropriate number for that partition.

3. Set up Asterisk or Freeswitch, or find some front-end if you don't like editing text files. Route your numbers through this.

4. Write a dialplan that has intelligent logic to properly route numbers from each partition. Give some partitions an audio captcha to solve to prevent automated bots before ringing your real number or device, send some straight to voicemail, etc. Use your imagination.

5. Use certain numbers for a particular purpose. LinkedIn? They should get one. LinkedIn MFA? Give them another, they're sell that out too in some countries. Facebook? Buying a new product? Have a large partition of numbers, and rotate through these plus your personal email domains. Maybe pick a nice vanity number and use this on your resume to track that.

It shouldn't have to be like this, but this keeps my phone calls to a minimum, and I can fairly reliably track the usage and sharing through variosu online services, and cut back on tracking and cross-service account associations using phone numbers as identifiers that the marketers love.