Lookup SIM Swap Overview

SIM swap fraud occurs when a scammer hijacks a victim's mobile phone number in order to take over their online accounts. To hijack a mobile phone number, the scammer will typically socially engineer a support agent at a mobile carrier, and port the victim's phone number to a SIM card that they control. After the SIM is activated, the scammer is able to receive the victim's texts and phone calls. They then begin to access their online accounts by going through account recovery flows that rely on SMS one-time passcodes or knowledge-based authentication, which the scammer has already collected answers for. These types of attacks can cause severe financial impact on an individual and unfortunately have been on the rise. Based on a study from Action Fraud, there has been a 400% rise in the number of SIM swap fraud cases in the United Kingdom during the last five years. With many well-known individuals being SIM swapped, you may have seen it in the news.

Even Europol has printed this notice to raise awareness on the scam:

sim_swap object, which has information about the last SIM change associated with the mobile number:

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{
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  "calling_country_code": "44",
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  "country_code": "GB",
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  "phone_number": "+447772000001",
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  "national_format": "07772 000001",
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  "valid": true,
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  "validation_errors": null,
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  "caller_name": null,
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  "sim_swap": {
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    "last_sim_swap": {
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      "last_sim_swap_date": "2020-04-27T10:18:50Z",
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      "swapped_period": "PT15282H33M44S",
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      "swapped_in_period": false
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    },
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    "carrier_name": "Vodafone UK",
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    "mobile_country_code": "276",
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    "mobile_network_code": "02",
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    "error_code": null
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  },
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  "call_forwarding": null,
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  "line_type_intelligence": null,
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  "url": "https://lookups.dublin.ie1.twilio.com/v2/PhoneNumbers/+447772000001"
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}

(information)

Info

The example request above uses the Ireland region (IE1). Check out Using Lookup with Twilio Regions for more information about how to select the Twilio Region that your request is processed out of. Lookup fully supports data residency using the IE1 region when making SIM swap requests to EU countries, as well as the United Kingdom.

The description of the fields returned in the last_sim_swap object is provided in the API docs, but it's important to understand the swapped_period and swapped_in_period fields. Let's unpack that.

Carriers provide their data to Lookup SIM Swap in a variety of ways. For example, not all countries or carriers will return the exact SIM swap date, but Lookup SIM Swap will return it as the last_sim_swap_date field when it's available. To standardize all these different methods of conveying SIM swap information, we use the fields swapped_period and swapped_in_period. Both of these values together allow you to answer a question like, "Was the SIM for this phone number swapped in the last 24 hours?" This is done by configuring the swapped_period field to hold the trailing time period that you're interested in knowing if a SIM has been swapped, for example 24 hours, and using the swapped_in_period field to indicate yes or no. Find more information about the field descriptions from the API docs.

To access Lookup SIM Swap, apply for use case approval from the major carriers in the country that you want to make lookups in. Some carriers may require that you have specific disclosures in your terms of service or privacy policy. Twilio will guide you through this process and submit your application(s) on your behalf. Carrier approvals can take between 2-4 weeks after which your account will be configured and you'll be off and running.

For the Beta, we are supporting countries in Europe, Latin America, and North America in the table below. However, we may not have complete coverage from all the major carriers in a given country. Pricing also varies based on country. Please reach out to us to our latest coverage, which is continually expanding, as well as detailed pricing information.

Europe: **

• France
• Germany
• Italy
• Netherlands
• Spain
• United Kingdom**

Latin America:

• Brazil
• Colombia

North America:

• Canada
• United States

In addition to SIM Swap, we are also offering our Call Forwarding package. This tells you if a user has configured their mobile phone number, with their carrier, to forward their calls to another phone number. You can use this to detect a potential compromise of a user's voice channel, which is useful prior to sending a voice one-time passcode or critical outbound voice communication. This feature is only available in the United Kingdom supporting major carriers; it also requires carrier pre-approval prior to use.