Device Idenity Leakage?

walker_p

Whenever I am in the vicinity of my doctors office, I immediately get a text asking me "have you arrived?".
This is unnerving. I have bluetooth services off, and location services limited to two open source apps "while in use". How is this company directly identifying my device?

de0u

walker_p Perhaps the text is sent based on the time of the appointment?

Is a text sent if the device visits the vicinity of the office on a day when there is not an appointment? Or if the device arrives near the office two hours early for an appointment?

Does the office have a Wi-Fi network that the device is signing in to? If so, what is the MAC-address setting for that Wi-Fi network?

Murcielago

walker_p

A few questions to narrow down the actual cause:

Do you have any medical/appointment apps installed and if so have you ever granted location permission to this app (not sure if I understood correctly what you meant exactly by
"bluetooth services off, and location services limited tot wo open source apps "while in use" - that's why I'm asking just to be sure)?

Is the message a normal SMS or in-app notification?

Does it also happen if you drive past the office without an appointment?

walker_p

I will get a text immediately near the office, sometimes an hour before. The texts correspond to my arrival, not proportionally before the appointment time. I have never used any wifi other than my own home wifi network. I am completely depending upon GrapheneOS default protections. I am certain this mammoth business somehow has my device recognized.

walker_p

BTW thank you for your response de0u.

Probably9857

Well, your carrier certainly knows your location.

Is it possible that your carrier offers a service to businesses where they will let them know when a customer is near their location?

Is it possible that you agreed to allow this, possibly without realizing what you were agreeing to?

The easiest way to figure this out might be to just ask your doctor's office. They will probably be happy to tell you if they really do have some kind of system that is doing this.

walker_p

I receive an SMS text. I have no apps other than GrapheneOS base apps, Breezy Weather, Organic Maps. I have no other services and no other permissions. I have not gone to the location to test if any appearance causes a text.
My doctor(s) are part of a huge group (hundreds). The system level information is not something they have much knowledge about, or interest in. Having gone to the group for years, I know they see no need for privacy.
My carrier could indeed sell location and I will ask. I'm sure they'll admit it upfront.
Thanks to you both.
The help here is first rate.

de0u

walker_p How about asking the doctor's office what triggers the message?

Is it possible that when you visit you bring some medical device that communicates via Wi-Fi or Bluetooth?

walker_p

No. Not possible.

walker_p

I will ask the group website people. They are the only staff that have any tech knowledge.
I do know Epic is behind the system.