How to find out if your mobile phone has been secretly hijacked

How to find out if your mobile phone has been secretly hijacked

We’ve all been told to be on the lookout for potential malware contaminating our devices. Infections often find their way to our computers, phones and tablets after clicking on a dangerous link, downloading an attachment from an unknown email or even downloading a malicious app from the Google Play Store.


Generally, these attacks target your devices, but is it possible for hackers to also work their way into your phone’s SIM card?


Image of a smartphone with the SIM card removed.

Image of a smartphone with the SIM card removed.
(Fox News)

Unfortunately, the answer is yes, as evidenced by this sad story shared with us by reader, Carol B.:

“My brother had a hacker get a SIMS card from his cell phone service. He then hacked into all his email accounts and changed the passwords. He proceeded to kill my brother and his wife’s SIMS cards on their phones so they don’t get alerts from their credit card companies, banks, etc. The hacker was able to hack into one of his bank accounts and get $1000 transferred using Zelle to an account.What can we do to prevent this from happening again?”

Why would a hacker want to hack into your SIM card?

To put it simply, the SIM card contains all the information that allows you to connect to your larger network through calls, texts and emails.

It stores your mobile subscriber number, which helps you authenticate and identify yourself on mobile devices. As a result, if someone successfully hacks into your SIM card, it gives them the ability to:

  • Gain access to two-factor identification codes, potentially allowing them to access your bank accounts and other high-profile accounts
  • Receive text messages from your contacts
  • Use your identity to text and call others for fraudulent schemes.

Most hackers hope to gain access to your SIM card to pull off any of these three fraudulent practices:

1. SIM change

Once they gain access to your SIM card, hackers will use your information to try to trick your service provider into changing your phone number to a new SIM card and phone number, resulting in the owner’s number and information being deleted. To do this, the original phone must be restarted to complete the transfer. This often requires the hackers to contact the original phone owner, posing as the service provider, to reboot their phones.

See also  35 malicious apps found on Google Play Store, installed by 2 million users

2. SIM cloning

In this case, after gaining access to your SIM card, the hacker will clone all the information contained on it and copy the stolen data to a new SIM card that they control. Once successful in this, it allows criminals to access all of the original owner’s texts, calls and location data, which the hacker can view on their device.

3. Simjacker spyware attack

Simjackers are spyware, often sent to people via an SMS message, that if opened, allow the hackers to read your messages, listen to your conversations and track your location. This is mainly achieved through software called [email protected] Browser, a kind of basic browser, primarily used by service providers to interact with web applications. While [email protected] Browser is installed on many devices making people vulnerable to Simjacker, it is also rarely used and these attacks are most common in the Middle East, North Africa and Eastern Europe


What are the chances of my SIM card being hacked?

Although we have now established that your SIM card can be hacked, and is very dangerous if it were to potentially happen, it is far less common than hackers gaining access to your devices. This is primarily because it is much less easy for criminal hackers to gain access to your SIM card and go unnoticed. For that matter, hackers can do many things they can do by hijacking your SIM card, such as using your identity to make calls and send text messages.

It’s also worth noting, back at the end of 2022, Apple no longer uses physical SIM cards in any of their newly launched products. Instead, they distribute electronic SIM cards known as an eSIM. Fortunately, eSIM cards are somewhat less vulnerable to hackers when it comes to the threat of SIM switching. Crooks and fraudsters can no longer claim that their SIM card is lost. But like all technology, it is unfortunately still possible to hack an eSIM card. With that in mind, it’s important to be on the lookout for some tell-tale signs that your SIM card may have been hacked – period.


How do I know if my SIM card has been hacked?

As mentioned above, there is some cold comfort to be taken in the fact that it is extremely easy to find out if your SIM card has been hacked.

You do not receive calls or text messages

Phone numbers can only be associated with one SIM card, so if you are a victim of SIM cloning or swapping, you will not receive new calls or texts. Have a friend call or text you, and if the call or text goes through, there’s no way your SIM card has been cloned or swapped.

Outgoing calls or text messages to unknown numbers

When you check your phone bill and you see multiple calls or texts to numbers you don’t recognize, it opens up a very real possibility that your SIM card has been hacked. Contact your service provider immediately for more information about these calls.

Messages asking you to restart your device

If you get a random text message asking you to reboot your device that appears to be from your service provider, it’s more than likely a scammer. They won’t be able to complete cloning or SIM swapping unless you reboot your device. Service providers will never contact you and instruct you to reboot your device, so if you get such a message, it’s best to call them immediately.

Your device appears in a strange location

One of the most guaranteed ways to tell if your SIM card has been compromised is if your phone shows up in a different location than yours while using a tracking app like Find My. However, many hackers will attempt to disable this service as a means of avoiding detection.

Inability to access accounts

Many apps and websites, especially those for banks or others that contain sensitive information, tend to use two-factor authentication. This is a way to bypass hackers who may have gained access to your login information by sending you a text message or email with a verification code. If your SIM card is hacked, they will be able to receive that code, giving them the ability to log in and change their username and password.


Picture of a SIM card in the case, outside the phone.

Picture of a SIM card in the case, outside the phone.
(Fox News)

How can I protect my SIM card from being hacked?

The chances of your SIM card being hijacked are relatively low. However, there are steps you can take to prevent this from happening to you.

  • Set all your social media accounts to “Private” or “Friends Only”– Hackers will often take the first steps to gain access to your information by searching for your public online presence
  • Delete apps or online accounts you no longer use – further limits the possibility of being hacked
  • Do not open attachments or click on links from strangers emails – chances are they are phishing scams, hoping to gain access to your personal information
  • Consider alternative methods of two-factor identification – instead of relying on a text message or email, consider a service like the Google Authentication app, which is tied to your device and prevents hackers from receiving a text message or email
  • Never use the same password for multiple accounts
  • Never select security questions where the answer is publicly available, such as “mother’s maiden name”.
See also  How to avoid being scammed or hacked


SIM card lock

The biggest security measure you can place on your SIM card is to enable a SIM card lock, which requires a PIN code for anyone trying to access your SIM card.

To activate a SIM card lock on an Android

  • Go to Settings
  • Press Lock screen and security
  • Press Other security settings
  • Press Set up SIM card lock
  • Turn on Lock the SIM card.

How to activate a SIM card lock on an iPhone

  • Go to Settings
  • Press Cellular
  • Press SIM PIN code
  • Enter your existing PIN codeand the SIM lock is activated.

Important note: Always make sure you know your current PIN before activating the lock.


Unlock your technology

My greatest desire is to educate and inform you about the increased real threat to each of our connected devices and encourage you to apply strong antivirus security protection to everything in your life that is connected to the rest of the world.

See my expert review of the best antivirus protection for your Windows, Mac, Android and iOS devices by searching “Best Antivirus” on by clicking the magnifying glass icon at the top of my website.

Related: Free Antivirus: Should You Use It?

Kurt's home screen "CyberGuy" Knutsson's website.

Home screen on Kurt “CyberGuy” Knutsson’s website.
(Fox News)

For more of my security tips, go to and be sure to subscribe to my free CyberGuy Report newsletter by clicking on the “Free Newsletter” link at the top of my website.


Copyright 2023 All rights reserved. articles and content may contain affiliate links that earn a commission when purchases are made.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *