Mobile network operators can provide information about you to an adversary.
They can provide:
- Given a name: the phone numbers registered under that name.
- Given a phone number: the name under which the phone number is registered and the IMEI number[1] of the phone in which the phone number is used.
- Given an IMEI number: the phone number that is used in the phone with that IMEI number.
Additionally, given your phone number, mobile network operators can provide (current and historical) data and metadata about your phone activity:
- The content of SMS and regular calls you make on your phone.
- The list of websites you visit on your phone.
- Your phone physical location.
- Metadata about your use of end-to-end encrypted messaging applications (e.g. when you use Signal and the approximate size of messages sent or received through Signal).
This means that any of the following conditions can allow an adversary, with the collaboration of mobile network operators, to access (current and historical) data and metadata about your phone activity:
- Knowing your name (if your phone is not anonymous).
- Knowing your phone number, which they can find by monitoring or seizing a phone in contact with yours, using an IMSI-catcher, or through advanced correlation techniques[2].
- Knowing your phone IMEI number, which they can find by seizing your phone.
Used in tactics: Incrimination
Mitigations
| Name | Description |
|---|---|
| Anonymous phones | You can use anonymous phones to make it harder for mobile network operators to provide useful information to an adversary. |
| Digital best practices | You can follow digital best practices to make it harder for mobile network operators to provide useful information to an adversary. For example, you can use end-to-end encrypted messaging applications on your phones, instead of traditional SMS and calls. |
| Encryption | You can encrypt “in-motion” data to make it harder for mobile network operators to provide useful information to an adversary. |
Used in repressive operations
| Name | Description |
|---|---|
| Case against Boris | Investigators used the collaboration of mobile network operators to intercept calls from Boris's phone or the phones of people close to him[3]. They regularly listened to the intercepted calls in real time and used information from the calls to adjust ongoing physical surveillance operations. Investigators used the collaboration of an email provider to gain real time access to an email address used by Boris: they were able to see emails sent and received in real time. |
| Mauvaises intentions | Investigators used the collaboration of mobile network operators to link phone numbers to civil identities, to know which phone numbers were in contact with each other, to geolocate phones (both retrospectively and in real time) and to record phone calls[4]. |
References
An International Mobile Equipment Identity (IMEI) number is a number that uniquely identifies a phone.
For example, if an adversary knows that you were in place A on Monday and in place B on Tuesday, and they know from cell tower data that a particular phone was the only phone that was also in place A on Monday and in place B on Tuesday, they can deduce the phone is yours.