How to Protect Against SIM Swap Fraud With Vonage Network APIs

Introduction 

This blog post will showcase real-world use cases of potential SIM Swap attacks and solutions using the Identity Insights SIM Swap Insight.

Setting and Situation

I hosted a fraud prevention workshop and asked the attendees to think about what comes to mind when they consider fraud. Some of the words they brainstormed were:

fraud examplesWhen prompted to discuss solutions for mitigating fraud, here's what they shared:

Fraud preventing solutionsThese are all valid responses, and I hope they inspire you. In this blog post, I would like to explore some fraud use cases and how Identity Insights, specifically the SIM Swap Insight, can offer solutions for your users.

What Is SIM Swap?

SIM swap fraud is a malicious attack in which criminals trick mobile providers into switching a victim's phone number to a SIM card they control. Once they have control of your number, they can bypass two-factor authentication (2FA) and access sensitive accounts, such as email, social media, and banking apps.

Methods Used to Obtain the Intelligence Needed to Carry out the SIM Swap

Attackers gather enough personal information before executing a SIM swap to convincingly impersonate the victim to their mobile carrier. I share below some of the methods they use to obtain such intelligence. 

Data Exposure and Identity Theft

I've kept an eye on data leaks; at times, I receive emails from Google or Have I Been Pwned. However, when considering your users, they can be impacted by having their personal or company data compromised through their phones, resulting in potential identity theft and severe reputational damage. Breaches like this can result in significant financial losses and regulatory penalties.

Social Engineering Attacks

I used to play a game called Gunbound; I thought I was making a good virtual friend within the game, he was asking questions that seemed like he wanted to know more about me such as what was the name of my first pet and the name of my primary school teacher…well, these happened to be my password recovery questions, I lost access to my account and had a hard time retrieving it.

Such social engineering attacks can occur in many contexts, including SIM Swap ones. The attackers often use social engineering to impersonate victims and convince mobile carriers to issue new SIMs. These scams typically begin by gathering personal information, often obtained through data breaches or social media, and using that information to bypass carrier security checks. The victims usually don't notice until they lose service, unfortunately, when the damage is already done.

Everyday Use Cases of SIM Swap Fraud

With enough personal intelligence in hand, attackers can execute a SIM swap and then exploit the victim's phone number across a wide range of high-value targets

Social Media Account Takeovers

Social media is a sensitive topic. Platforms are where folks share their personal information, and many companies also use social media for business purposes. If a scammer gets control over a phone number, they can use SMS-based features to post on your behalf or reset your account passwords. They can also receive and make phone calls from the SIM-swapped number, i.e., allowing them to receive a phone call to verify they are the 'owner' of the number or social media/bank account. This can result in reputational damage and lead to further scams or the leak of private data.

In Detect SIM Swap Fraud With Enterprise-level Security Checks, I show an example of a typical bank web application login page for today's tutorial. When the SIM Swap Insight checks with the mobile carriers to see if any recent changes have been made to the SIM's phone number, the user cannot log in if such changes have occurred. Otherwise, they'll be able to log in to their account.

Cryptocurrency Theft

I've seen so many crypto theft use cases in the news, and the impact is massive; these victims have lost too much money. Users of cryptocurrency exchanges are especially vulnerable to SIM swap attacks. When attackers gain control of a user's phone number, they can bypass two-factor authentication (2FA) and steal funds from cryptocurrency wallets connected to these platforms. These attacks put millions, if not billions, of dollars' worth of digital assets at risk.

Banking Fraud

I vividly remember being on my way to take my ENEM test in Brazil when a guy approached me with a story: he had lost his wallet. He would miss his flight, speaking very anxiously and asking to be let off with some money. He walked me to the bank. He made it seem like I could trust him, even offering his phone or wedding ring as a form of knowing he'd keep his word. I could trust him - that was the end of the story. I not only lent him my money but never saw it again; hopefully, all of this kicked in after my test, and it didn't affect my ability to focus on it that day.

There are so many cases of bank fraud and even SIM Swap attacks. These attackers can access a victim's phone number, request OTPs (one-time passcodes) from the bank, and complete transactions under the victim's name. These attacks often follow online identity verification steps, such as for job applications or rental agreements, leaving another layer of exposure if documents are compromised.

How Do I Safeguard My Users Against Fraud?

There are many targets, including banks, financial institutions, fintech companies, crypto exchanges, cybersecurity vendors, payment processors, e-commerce platforms, retail stores, IT departments, ticketing agencies, social networks, and mobile operators. The list goes on. Integrating the Identity Insights SIM Swap Insight can provide the necessary security to prevent and mitigate these attacks.

To help protect your users from SIM swap fraud, Identity Insights offers a valuable capability: the SIM Swap Insight. You can programmatically check whether a phone number's SIM card has been recently changed, adding a key layer of security to sensitive actions such as logins, account recovery, and financial transactions. If a SIM change is detected, organizations can trigger step-up authentication, block access, or flag the session for investigation. 

What Can You Do With the SIM Swap Insight?

The SIM Swap Insight verifies whether a SIM card linked to a given phone number has recently changed, and can also return the timestamp of the most recent SIM swap. You can check for a SIM swap within a specified window of between 1 and 2400 hours using the period parameter.

The Identity Insights API is available via a single endpoint that accepts all insight requests:

POST /identity-insights/v1/requests

The API is available across multiple regional endpoints to support data residency requirements:

The response includes an is_swapped boolean indicating whether a swap occurred within the defined period, as well as a latest_sim_swap_at timestamp indicating when the most recent swap occurred.

Conclusion

Bad actors will continue to develop new fraud methods; relying solely on SMS-based authentication is no longer enough. Have a look at Identity Insights and find solutions to mitigate fraud.