We have all heard the horror stories about travellers who have become victims of cyber-crime while accessing what they assumed were secure public Wi Fi networks. The simple reality is that there is no guarantee that these networks are secure, and unless you are using a VPN app, important transactions such as banking should be done while accessing mobile operator networks.
Does this mean that my information will be safe? What if hackers hack into my SIM card? What information is stored on my SIM card? We answer these questions and more in this article.
Make sure that you know what your options are when it comes to a Global SIM card.
What information is stored on a SIM card
A SIM card, also known as a subscriber identity module, is a smart card that stores identification information that pinpoints a smartphone to a specific mobile network.
Data that SIM cards contain include user identity, location and phone number, network authorization data, personal security keys, contact lists and stored text messages. SIM cards allow a mobile user to use this data and the features that come with them.
It is important to note that passwords are not stored on a SIM card unless they are communicated via a text message. Do not share sensitive information via text messages.
If you are travelling internationally, there are benefits to having an international SIM card. Further reading: What is a travel SIM card? (2022 international travellers guide).
Benefits of storing data on a SIM card
It is important to note that there is compulsory data that is stored on a sim card. Information such as the SIM cards Integrated Circuit Card ID number, and the phones International Mobile Equipment Identity is compulsory data that is stored on the phone. This data allows a user to access mobile operator networks.
An International Mobile Subscriber Identity number is a number that identifies a subscriber that access a mobile network as opposed to a phone. That is stored on a SIM card and changes from person to person. The advantage of this is that if there is an emergency, a person’s location can be tracked using a IMSI number.
Data such as contacts and text messages can be stored on a SIM card. The advantage of this is that a user does not have to carry around a phone book to access numbers or a note pad to write down messages.
Disadvantages of storing info on a SIM card
There are some disadvantages of storing information on a SIM card.
Not many people can recall numbers from memory because they scroll to a name and just press dial. They don’t physically key in the number. This means that you do not pay attention to the number and if your contact list is lost or SIM card is corrupted, you lose all of this data.
Text messages can also be lost if the SIM card is lost or corrupted. Additionally, hackers can read text messages form a sim card. This is particularly disconcerting as banks use text messages to communicate One Time Pins which allows users to access their accounts or approve transactions. If hackers gain access to your banking app, this can have significant ramifications.
SIM card technical design & structure
A SIM card is an integrated circuit (IC) intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers).
Technically the actual physical card is known as a universal integrated circuit card (UICC); this smart card is usually made of PVC with embedded contacts and semiconductors, with the SIM as its primary component. In practise the term “SIM card” refers to the entire unit and not simply the IC.
The first SIM cards were the size of credit and bank cards; sizes were reduced several times over the years, usually keeping electrical contacts the same, so that a larger card could be cut down to a smaller size.
What is the SIM card storage capacity?
SIM cards can come in various data capacities, from 8 KB to at least 256 KB. All can store a maximum of 250 contacts on the SIM, but while the 32 KB has room for 33 mobile network codes (MNCs) or network identifiers, the 64 KB version has room for 80 MNCs.
Make sure that your family and friends can contact you while you are travelling. Further reading: What is international roaming & how it works.
SIM card data security
Like all technology, SIM cards are not fully protected against hacks. Hackers can hack your SIM card and can access some important information from it.
In September 2019, security researchers at AdaptiveMobile Security announced they had discovered a new security vulnerability they called Simjacker. This complex attack carries out SIM card hacking by sending a piece of spyware-like code to a target device using an SMS message.
If a user opens the message, hackers can use the code to spy on their calls and messages—and even track their location.
Another SIM card security issue you may have heard of is SIM card swapping. Hackers used a variation of this technique to take over Twitter CEO Jack Dorsey’s personal Twitter account in August 2019. This event raised awareness of how these attacks can be destructive. The technique uses trickery and social engineering, rather than technical vulnerabilities.
To perform a SIM card hacking through a SIM card swap, a hacker will first call up your phone provider. They’ll pretend to be you and ask for a replacement SIM card. They’ll say they want to upgrade to a new device and, therefore, need a new SIM. If they are successful, the phone provider will send them the SIM.
Then, they can steal your phone number and link it to their own device. All without removing your SIM card!
Many times, people try to put SIM swapping and SIM cloning under that same umbrella. However, SIM cloning is more hands-on than the other option.
In a SIM clone attack, the hacker first gains physical access to your SIM card and then creates a copy of the original. Naturally, for copying your SIM card, the hacker will first take out your SIM from the smartphone.
They do this with the help of a smart card copying software, which copies the unique identifier number—assigned to you on your SIM card—onto their blank SIM card.
The hacker will then insert the newly copied SIM card into their smartphone. Once this process is complete, consider your unique SIM card identity to be as good as gone.
- Protect Against Socially Engineered Attacks. To protect against SIM card swaps, make it hard for hackers to find information about you. Hackers will use data they find about you online, such as names of friends and family or your address. This information will make it easier to convince a customer support agent that they are you. Try to lock down this information by setting your Facebook profile to friends-only and limiting the public information you share on other sites. Also, remember to delete old accounts you no longer use, to prevent them being the target of a hack; and
- Set a SIM Card Lock. To protect against SIM attacks, you should also set up some protections on your SIM card. The most important security measure you can implement is to add a PIN code. This way, if anyone wants to modify your SIM card, they need the PIN code.
What type of data can be stored on a SIM card
As pointed out above. Important information such as the phones ICCD number, the phones IEMI number as well as the users IMSI number are all stored on a SIM card.
Additionally, a users contacts and text messages are stored on a SIM Card.
How to find what is stored on a SIM card
The most obvious way to find out what is stored on a SIM card is through a phone.
You may also find out what is on a SIM card by transferring the information to your computer through a SIM card reader.
Obtain a SIM Card Reader.
- Step 1: obtain a SIM card reader and driver. This can be purchased from a local computer store or online via websites such as www.dekart.com. (See the References and Resources section of this article for direct links to other options.);
- Step 2: install the SIM card-reader driver in your computer. If you have bought the card reader online, the driver program will be an executable file, ending with the extension “.exe” (for example, SimCardReader.exe); and
- Step 3: complete the installation and restart your computer, if necessary.
Transferring SIM Card Data to a Computer
- Step 1: insert the SIM card into the SIM card-reader slot. Connect the SIM card reader to your computer using a USB cable. Plug the USB cable in any USB port in your computer;
- Step 2: allow your computer to detect the device. The SIM card reader might appear on your desktop as a removable drive. Launch the SIM card-reader program if it does not open automatically. A graphical user interface will display;
- Step 3: click on the “Download” or “Read” button to retrieve the data in your SIM card. Allow time for this process to complete without interruption; and
- Step 4: browse through the program’s viewing windows to find out the contents of the SIM card.
SIM card storage FAQ’s
- What information is stored on my SIM card?
Important information such as the phones ICCD number, the phones IEMI number as well as the users IMSI number are all stored on a SIM card. Additionally, a users contacts and text messages are stored on a SIM Card.
- Can hackers access the information that is stored on my SIM card?
Hackers can read text messages form a sim card. This is particularly disconcerting as banks use text messages to communicate One Time Pins which allows users to access their accounts or approve transactions. If hackers gain access to your banking app, this can have significant ramifications.
- Is the data on a SIM card unique to me?
The ICCD and IEMI numbers are unique to a SIM card. Additionally, the International Mobile Subscriber Identity number, the contact list and text messages that are sent to a phone are unique to the user of the sim card.
- Is there a way to read the information from a SIM card without a phone?
Yes. This is done through a SIM card reader which can be installed onto a computer.
- Can SIM cards be corrupted?
Yes. When this happens, your contact list and text messages will be lost. It is therefore important to back up any information that can be backed up onto the cloud.
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