Hackers could get to clone your sim card without you noticing. To do this they can use social engineering and impersonate your identity. This is a serious problem, since they could act on your behalf, receive 2FA codes to access your accounts, make calls or send SMS, etc. There are some warning signs that may indicate that your mobile card has been cloned or, at least, that there is something strange.
Signs that your SIM card has been cloned
This type of attack is known as SIM-swapping. Basically, a cybercriminal is going to manage to clone your mobile card. It will always use some strategy to achieve it, either by deceiving the telephone company or the user himself. Luckily this is not a common problem in Spain, since there are important security measures. However, it is convenient to know what signs there could be and thus avoid problems.
you do not receive calls
One of those signs is that you do not receive calls. You even try to call yourself from another mobile, it gives a signal but you do not receive anything on the mobile. There is something strange and you begin to suspect that perhaps you do not have control of your SIM card and someone has been able to clone it without you realizing it.
This problem is undoubtedly one of the most common. Perhaps you received a strange call, alerting you to a supposed problem, and that was actually what triggered your card to be stolen. From then on you would no longer be able to receive calls.
SMS do not arrive
Something similar happens with SMS. Hackers, in fact, aim to clone mobile cards precisely to gain control of text messages. In this way they will be able to receive two-factor authentication codes, for example, and access bank accounts, social networks, etc.
if you see that an SMS does not reach you, if you verify that it should indeed arrive and you also see that you do not receive calls either, it is undoubtedly a sign that something is happening. It does not always mean that it is a SIM Swapping attack, but it is a possibility.
you have lost connection
Another sign that you will have is if you see that you have lost Connection. You try to connect again and again, you are in an area with coverage, but nevertheless you see that it does not work. It is as if you did not have a SIM card inserted and your mobile phone will not receive a signal of any kind and you will not have calls, SMS or Internet.
Although this can happen for many reasons, such as a failure with the line, poor coverage or even problems with the SIM card that has been damaged, the truth is that it could also be due to a mobile card cloning.
The phone has a different location
If you check the Location of your phone and it appears as if you were in another place, as if your mobile line was in another city or country, that is a clear sign that your card has been cloned without you realizing it. It is something that should alert you and quickly take action, such as calling the phone company.
The normal thing is that whoever clones your SIM card is in another physical place. Basically what you are going to do with a SIM Swapping attack is to impersonate your identity and receive a physical card as if it were you. It’s not going to be someone you’re close to, so seeing that the location has changed is a good sign.
You get strange messages
You may also begin to receive strange messages, that you do not fully understand the reason. It may be that the hacker himself is sending you instructions to supposedly solve a problem with the line. This is what could allow it to clone your card, so you should never fall into this type of trap.
Likewise, that cloning may have already occurred and you start receiving strange emails, either from the attacker or from other services you use or are using on your behalf. It is another cause for alert.
In short, as you can see these signs will help you to be aware that your SIM card has been cloned. Avoiding attacks that use the SIM is essential. You should always keep common sense, have the devices protected and updated.