Identity theft in WhatsApp groups: risks and defenses

Formarse » Free online courses » Identity theft in WhatsApp groups: risks and defenses

WhatsApp has become the perfect place for friends, family, and work to coexist in the same digital space.But it's also a very attractive breeding ground for scammers and cybercriminals. WhatsApp groups, in particular, bring together many people at once, meaning a single scam can affect dozens or even hundreds of users in a matter of minutes.

Identity theft in WhatsApp groups and the frauds organized through them are a growing problem.This is happening both in Spain and in other countries. From organized financial scams carried out by large groups to account thefts used to deceive your contacts, the methods are becoming increasingly sophisticated and difficult to detect if you don't know what to look for.

What is digital identity theft and how does it affect WhatsApp?

When we talk about digital identity theft, we are referring to any situation in which someone uses your personal data without permission to impersonate you.Whether it's with a company, a bank, an online platform, or your own contacts, the goal is usually to obtain money, access accounts, contract services in your name, or simply damage your reputation.

In the online environment, impersonation is not limited to just "hacking" an accountThis also includes creating fake profiles with your photos, using your phone number, duplicating your SIM card, or impersonating you with a company to obtain a duplicate line or financial products. All of this, when applied to WhatsApp, allows a third party to communicate with your contacts as if they were you.

There does not need to be direct economic harm for it to be considered a crimeThe mere act of impersonating another person, even on a one-off basis, can have legal consequences. For example, contracting a phone line with your information, opening a bank account in your name, or logging into WhatsApp using your number without your permission are all actions that could be prosecuted.

On WhatsApp, impersonation can range from the complete cloning of your account to the creation of a profile that uses your photo and name.Or the reuse of an old number of yours that now belongs to someone else but still appears in your contacts' address book under your name. All of this is exacerbated when the scenario involves groups, where the reach of the scam multiplies.

SIM swapping and fraudulent SIM card duplication

One of the most dangerous techniques that is growing in Spain is the so-called SIM swapping or fraudulent SIM duplicationIn this type of attack, the criminal gets the operator to issue a new SIM card associated with your number, rendering the one you have in your mobile phone useless.

To achieve this, scammers collect the victim's personal data through phishing, social engineering, or database leaks.Full name, ID number, date of birth, security answers, etc. With this information, they call the operator pretending to be the owner and claim a credible excuse (loss, theft or damage to the mobile phone) to request a duplicate of the card.

As soon as the company activates the new SIM, your original card will no longer have service.The phone suddenly loses signal and you can't receive calls or SMS messages. From that moment on, all verification messages (including those from banks, online platforms, and WhatsApp) are sent to the criminal's device, giving them complete control of the number.

With control of the phone number, the attacker can reset passwords, access online banking, authorize transfers, or register WhatsApp on a new phone.In Spain, there have already been cases of scams involving tens and hundreds of thousands of euros using this system, with coordinated operations in provinces such as Barcelona, ​​Valladolid, Melilla, and different areas of Catalonia.

Law enforcement agencies consider SIM swapping a growing threatPrecisely because it doesn't require extensive technical knowledge, but rather the skillful use of the victim's personal information and verification lapses by mobile carriers. And, once WhatsApp is added to the equation, impersonation can affect not only your wallet, but also your inner circle.

Theft and cloning of WhatsApp accounts

Another widespread method is the direct theft of the WhatsApp account, which many call "cloning" or "hacking" of WhatsApp.The goal is to register your number on someone else's device so that the attacker can completely control your chats and your identity within the application.

There are two main ways to achieve this account hijackingThey can either exploit a successful SIM swap (the criminal requests the verification SMS after obtaining your number) or resort to pure social engineering. In this second option, the scam usually begins with the compromised account of someone you know.

The typical scheme is simple but very effectiveA scammer takes control of a friend or family member's WhatsApp account and messages them from their account, "Hey, I just accidentally sent you a text message with a 6-digit code, can you send it to me? It's urgent." Verification codeActually, it's the code WhatsApp sends to verify your number. If you forward it, you're literally handing over the keys to your account.

The moment the attacker enters that code into your phone, your WhatsApp session will automatically close. And the account becomes active only on their device. From there, they can read your conversations, contact your groups, ask your contacts for money under the guise of emergencies, or even spread messages that damage your reputation.

The Civil Guard, the Ertzaintza and the Mossos d'Esquadra have warned of an increase in these account seizures and they strongly recommend never sharing the verification code, even if it seems like someone you trust is asking for it. Furthermore, they insist that Activate WhatsApp two-step verification to add an additional PIN to stop these types of attacks.

WhatsApp groups: a hotbed of scams, fraud, and impersonation

WhatsApp groups, especially when we are added without being asked or when they go viral through invitation links, are an ideal environment for identity theft and mass scams.Many potential victims are concentrated in the same chat room, and the contagion effect is very rapid.

A clear example in Spain has been pointed out by the National Securities Market Commission (CNMV)which has detected a proliferation of WhatsApp groups supposedly dedicated to financial education and investment recommendations. In reality, these are setups created by criminals to direct users towards platforms and securities completely controlled by them.

The scheme usually works like thisSomeone invites you to a group where "experts" discuss market movements and recommend buying shares of small-cap foreign companies. At first, the recommended trades seem to work well; participants make some money and are encouraged to invest more and even invite acquaintances.

Once they have built trust, they launch the supposed “great opportunity”They ask you to invest large sums in a specific stock with the promise of spectacular profits in just a few days. Once the money is invested, the stock price plummets, the supposed experts recommend holding on or investing more capital, and shortly after, the administrators disappear and expel the victims from the group.

The CNMV emphasizes that no one can guarantee quick and secure profits in the financial markets.It warns that these groups are unauthorized. It recommends being wary of any promises of easy money, always verifying the identity of anyone advising you, and never providing personal or banking information or copies of documents through these chats.

Specific risks in unknown groups: malware, blackmail, and data exposure

Beyond financial scams, unknown WhatsApp groups are a gateway to all kinds of security and privacy risks.Often, we end up in a group without having given clear consent or without knowing most of the participants.

One of the most frequent dangers is the sending of fraudulent messages within the groupThese attacks aim to obtain passwords, card numbers, bank details, or even photos of personal documents. The attacker can impersonate an administrator, a company, technical support, or a contact you already know.

Attachments (images, videos, documents) containing viruses, Trojans, or other malware are also circulating. It's capable of stealing information, spying on the device, or even taking some control over it without the user noticing. The problem is compounded if you have automatic file downloads enabled, because you don't even get to decide whether you want to open them or not.

Another major risk is the massive exposure of personal information within those groupsMany people share work details, family information, third-party phone numbers, locations, or photos without knowing who is actually reading them on the other end. This information can be used for blackmail, targeted attacks, or more sophisticated identity theft.

The attackers also often spread invitation links to the group through social media or other channels.This allows them to accumulate victims on a large scale for spam campaigns, scams, or the distribution of illicit content. This is often done using fake or impersonated identities to gain trust.

Control who can add you to groups and how to leave them safely.

A first line of defense against dangerous groups is to properly adjust your WhatsApp privacy settings.By default, anyone can be added to a group, but the app allows you to change this and limit who has permission.

From Settings > Privacy > Groups you can choose between “Everyone”, “My contacts” and “My contacts, except…”If you choose "My contacts," only people saved in your address book will be able to add you to groups. And with the "My contacts, except…" option, you can still block specific contacts from adding you.

If you've already been added to a strange or suspicious group, you can leave it immediately using the "Leave group" option.The app will show you who has added you, which can help you identify if it's someone abusing your trust or an unknown number.

WhatsApp also allows you to report a group If you believe a group has fraudulent purposes, contains offensive content, or you were added without your consent, you can report it. By doing so, the platform receives up to the last five messages in the group, the chat ID, and certain technical data to evaluate the report. Other members are not notified that you have reported anything.

To reinforce your safety, in addition to leaving and reporting, it's a good idea to review what information you shared in that group. And, if you provided sensitive personal information, consider changing your passwords, notifying your bank, or taking extra precautions in the following days.

Report and block problematic contacts within groups

You don't have to limit yourself to reporting the entire group; you can also flag specific messages that you consider dangerous or abusive.Simply press and hold the message, go to the options menu and choose “Report”.

When you report a message, WhatsApp sends its systems the information needed to analyze the case. (sender details, time of sending and message content) and thus be able to act against accounts that send spam, scams or targeted threats.

In addition to reporting, you can block the contact that is causing problems.so that they can no longer message you privately or call you through the app. Their messages will still appear in the groups you're both in, but your direct interaction with that person is cut off.

It is also possible to block administrators or specific members of the group if you detect dangerous or abusive behavior.This doesn't eliminate the group or prevent them from continuing to talk to each other, but it does protect you against direct attempts at deception or harassment.

These blocking and reporting functions are key to curbing the activity of malicious accounts.And they are even more effective when several users in a group report the same person or chat, as the platform detects patterns of behavior.

Download settings and caution with shared links

One of the most common attack vectors in these groups is the sending of malicious files that are automatically downloaded to your mobile phone.By default, WhatsApp usually downloads images, videos, and documents when you're connected via WiFi or mobile data, unless you change it.

To reduce risks, it's advisable to disable automatic downloads from the app's storage and data settings.This way, only what you manually select will be downloaded, giving you time to consider whether the file makes sense, who sent it, and whether it could be dangerous.

Something similar happens with shared links within groups.Many attacks begin with a simple link that leads to a fake website where login information is stolen or malware is installed. Even if the link is sent by a contact you know, that person may have already been a victim and is unknowingly forwarding the message.

The basic recommendation is to be wary of shortened URLs, incredible promotions, supposed raffles, and messages like "check this out quickly before it gets deleted."At the slightest suspicion, it's best to ask the sender directly through another channel or warn within the group itself to prevent others from falling for it.

Some financial frauds detected by the CNMV also begin with links to unregulated investment platformsThese websites promise to operate using artificial intelligence, offer exotic bonds, or manage portfolios with guaranteed returns. Before investing a single euro through these platforms, it's advisable to check the official records of the CNMV (Spanish National Securities Market Commission) to see if the entity is authorized.

The trap of old contacts and reused numbers

A less well-known, but very real, risk has to do with the old numbers we keep in our address bookPhone operators reuse numbers that have been deactivated or canceled, so that mobile phone that previously belonged to your friend may now belong to a complete stranger.

On WhatsApp, however, that number will appear on your mobile phone with the name you originally gave it.such as “Mom”, “John – work” or “Carlos from the gym”. If the new owner of the number is a scammer (or someone unscrupulous), they can start a conversation with you and you will believe you are talking to your old contact.

This situation opens the door to very convincing impersonations.The new owner of the number can ask you for money, personal data, verification codes, or sensitive information, taking advantage of the trust you feel based on the name you see on the screen. And if they join groups where that person was previously a member, the scam is even easier.

The best way to reduce this risk is to "clean up" your contacts from time to time.Deleting numbers you don't even remember, or that you know no longer use that phone. It's the same as when you delete old photos that don't add anything to your life, but applied to your contacts.

If someone you know tells you they're changing their phone number, it's a good idea to delete the old one as soon as you save the new one.This way, you prevent a third party from inheriting that number in the future and taking advantage of the trust associated with that name in your contact list.

Warning signs that you may be being impersonated

Although it's not always easy to detect in time, there are several signs that can indicate someone is using your identity or number without permission.Paying attention to these signs can save you a lot of trouble.

One of the clearest clues is the sudden loss of mobile phone coverage for no apparent reason.If you suddenly lose service in an area where you normally have signal and the problem persists, it is essential to call your operator from another phone and ask if a duplicate SIM card has been issued.

Other signs include verification code alerts, password recovery emails, or notifications of new logins that you did not request.Whether it's from banks, email, social media, or even WhatsApp, this could mean someone is trying to access your accounts or has already succeeded.

Any unusual messages from your contacts also deserve attention. where they tell you they've received requests for money or strange communications supposedly sent by you. Sometimes, the first sign that you've been impersonated comes precisely from a friend who's suspicious and calls you to confirm.

Regularly checking your carrier's bill or online customer area can help detect SIM duplicate requests, card changes, or charges you don't recognize.These are clues that, when put together, can confirm that someone is using your number or your data.

What to do if your WhatsApp account is stolen or you suspect impersonation

If you suddenly lose access to your WhatsApp account or see that the app is asking you for the verification code again without your request, you may need to contact us.It is very likely that someone is trying to register your number on another device.

First of all, try Recover your WhatsApp account Reinstalling WhatsApp and verifying your number again with the SMS you'll receive. In many cases, this will expel the intruder. Once inside, activate two-step verification from Settings > Account and set a PIN that only you know.

If you are unable to recover your account, contact WhatsApp support. from the app itself (Settings > Help > Contact Us) or by sending an email to their official support address, explaining that your account has been stolen and requesting its temporary deactivation while it is investigated.

At the same time, it's advisable to notify your contacts through other means (call, SMS, email or social networks) to inform them that your account has been compromised.This will prevent them from falling for requests for money or fraudulent messages sent in your name.

If the identity theft involves unauthorized access to your online banking, purchases, or other unusual activityCall your bank immediately to block transactions, review recent transactions, and strengthen security measures (change passwords, block cards, etc.).

Reporting, evidence gathering, and legal protection

In the event of any identity theft or fraud through WhatsApp and its groups, it is essential to file a formal complaint with the security forces.In Spain you can go to the National Police, Civil Guard or regional police forces depending on your place of residence.

When reporting, bring with you all the evidence you can gather.Screenshots of messages, group data, phone numbers involved, confirmation emails for transactions you didn't make, suspicious bank transactions, etc. The more detailed the account of the events, the easier it will be for the investigation to move forward.

It is very important to keep all documentation related to the incident.From phone bills showing a duplicate SIM card to bank statements with fraudulent charges, keep a copy of the police report and note key dates and times to accurately reconstruct the timeline.

If the problem has gone further and you receive a court summons for crimes you did not commit (For example, scams perpetrated using your identity), you shouldn't ignore it. Always consult a criminal lawyer who can explain that you are a victim of identity theft and provide the evidence to support it.

In these situations, the burden of proving your innocence requires acting quickly and judiciously.The courts can recognize your status as a victim once the misuse of your data is proven, but the road to that point can be long if you are not properly advised from the beginning.

Identity theft in WhatsApp groups is much more than a simple technological scareIt can leave you without access to your accounts, empty your savings, damage your reputation, and land you in legal trouble without you even realizing it. Maintaining basic digital hygiene—checking who adds you to groups, cleaning up old numbers from your contacts, being wary of easy money promises, enabling two-step verification, and reacting quickly to any suspicious activity—makes a huge difference between being an easy target and a user who is much harder to scam.