SMS spoofing: what it is, how it works, and how to avoid falling into the trap

La identity theft via SMS and calls It has become one of the most dangerous and common scams affecting both individuals and businesses; check out the latest News about computer security and cybersecurity.

In this article we will explain in detail What is SMS spoofing, how does it work, and how is it related to other types of spoofing? (in calls, emails, websites, IP, DNS, GPS, etc.), as well as the signs to detect them and the practical measures you can apply to protect yourself in your daily life, both personally and professionally, and in matters of security and privacy in programs.

What is spoofing and why is it so dangerous?

When we talk about spoofing, we are referring to a set of identity theft techniques These are used by attackers to impersonate a trusted person, company, or organization. The goal is always the same: to trick the victim into revealing sensitive data, making payments, or performing actions that benefit the scammer.

Cybercriminals combine spoofing with various forms of Phishing (deceiving to steal data)These scams can occur via email, SMS, phone calls, or fake websites. In the banking sector, these scams focus particularly on capturing online banking credentials, card details, SMS verification codes (OTP), or other personal information that can be used to commit financial fraud or even other identity theft crimes.

It is important to remember that Reputable financial institutions do not ask for information via SMS, phone, or email. Information such as online banking username and password, codes sent to your mobile phone, card number, expiration date, or the three-digit security code (CVV/CVC) should be requested. If someone asks for this information through these channels, you should be immediately suspicious.

SMS Spoofing: What it is and how it works

El SMS spoofing It is the technique that allows an attacker to send a text message that appears to come from a legitimate sender (usually a bank, courier company, or government agency), when in reality it is sent by a criminal. This practice is often used in a variant of phishing called smishing, in which the deception arrives via SMS.

In practice, the con artist Modify the sender's number or name which you see on your mobile screen (the field known as Sender ID). Thanks to this, the fraudulent message can appear in the same SMS thread where you previously received legitimate communications from your bank or a trusted service. This appearance of continuity makes the user lower their guard.

The contents of these SMS messages usually include alarmist or urgent noticesThese scams often include: unrecognized charges, imminent account closure, the need to update information, supposed prizes or tax refunds, among others. From there, they invite you to click on a link or call a phone number that doesn't actually belong to the impersonated entity.

One of the most common tactics is for the message to contain a link to a fake website that imitates the bank's websiteThis page can be almost identical to the real one: logos, colors, similar text, and even a very similar URL. The goal is for you to enter your online banking credentials, card details, and codes you receive via SMS so the criminal can access your account.

In other cases, the SMS directs the victim to a fraudulent phone numberwhere a supposed “manager” or “agent” poses as bank staff, requests private data and guides the person step by step to authorize transfers or payments, believing that they are “solving a security problem”.

Why fake SMS messages get mixed up with official ones

One of the most frequent questions is how it is possible for a fraudulent message appear within the same thread than legitimate SMS messages from the bank. The explanation lies in how mobile phones and networks handle the sender identifier.

The devices group conversations based solely on the Sender IDThis alphanumeric field lacks robust verification and global legal validation. In other words, the network and mobile devices assume that anyone claiming to be "Bank X" or using a specific number actually is, without strict controls.

This loophole allows cybercriminals usurp the shipping name used by banks and companiesSince there is no strong authentication of the alias holder, the user's terminal mixes fake messages with legitimate ones, creating an appearance of complete normality.

The result is that even attentive and experienced users They may fall into the trap, since the channel and context (the message thread from "your bank") seem completely authentic, and the tone of the message plays on fear, urgency, or the feeling of financial loss.

Caller ID Spoofing: Impersonation in telephone calls

El Caller ID spoofing Phone spoofing is the equivalent of SMS spoofing but applied to calls. Instead of manipulating the sender of an SMS, the attacker falsifies the number that appears on the caller IDThus, the mobile phone screen may display the real number of the bank, an official body, or even a known contact, even if the call originates from elsewhere.

With this technique, the scammer pretends to be bank employee, account manager, or staff of an official service and contacts the victim claiming an urgent problem: suspicious movements, unauthorized access attempts, card blocking, need to verify data immediately, etc.

During the call, the person on the other end usually asks very sensitive data: digital banking username and password, codes received by SMS, full card number, PIN, personal data (ID, date of birth, address) or even that the victim makes transfers "to block fraud" that are actually being directed to accounts controlled by the criminals.

The consequences can be serious: direct access to bank accountsThis includes unauthorized transfers, opening accounts in the victim's name, or identity theft to commit other crimes. Therefore, if you are asked for security information during a call, you should hang up and call the bank's official phone numbers yourself.

To identify a possible case of Caller ID spoofing, it is advisable to look at whether They insist on the urgency of carrying out an operation, if the tone is intimidating, or if the questions are out of the ordinary (for example, asking for complete passwords or codes that the bank never asks you for over the phone).

Other very common types of spoofing

Although SMS spoofing and Caller ID spoofing are especially dangerous in the financial sector, there are other methods as well. many other variations of spoofing who also seek to deceive and steal information or money. Understanding them helps to recognize patterns and protect yourself better.

Email spoofing

On email spoofingThe attacker sends emails that appear to come from a legitimate address: a bank, a well-known company, or even a personal contact. The trick is to spoof the sender (FROM) field, so that at first glance the domain seems trustworthy, although upon closer inspection it usually is. slightly different from the real domain of the entity (for example, change a letter, add a hyphen, or use a different extension).

These emails usually ask the user provide personal or financial dataDownload an attachment or click on links that lead to fraudulent pages. In many cases, these are used to install malware (viruses, Trojans, keyloggers) or to open a website identical to the bank's, where the victim will enter their credentials.

Website or domain spoofing

El web spoofing or domain spoofing This involves creating a fake website that mimics a legitimate one (bank, online store, government agency, etc.). The URL displayed in the browser's address bar is usually very similar, but not identical, to the real site's URL. Attackers often combine this technique with SMS or email spoofing to drive traffic to these fraudulent sites.

Once on the fake website, the victim enters your login credentials, card details, or other confidential information believing they are on the original page. Criminals capture this data in real time and can immediately use it to access the account, make purchases, or empty balances.

IP spoofing

On IP spoofingThe cybercriminal spoofs the IP address of another computer so that the target system believes the connection originates from a trusted source. In this way, they can evade security filters, access restricted resources or take advantage of the trust that exists between machines on the same network.

This type of attack is often used as part of more complex strategiessuch as denial-of-service (DDoS) attacks or intrusions into corporate networks, and can allow the theft of confidential information if adequate protection measures are not in place.

DNS Spoofing

El DNS spoofing It relies on manipulating the Domain Name System (DNS), which translates website names into IP addresses. Attackers infect the victim's router or computer, or manipulate DNS responses, so that when the user visits a known website, they are silently redirected to a malicious site. fraudulent site controlled by them.

From the user's point of view, everything seems normal (they type the URL they always use), but in reality they are entering a manipulated website where they can steal credentials, bank details, or install malware without realizing it.

GPS Spoofing

El GPS spoofing It involves spoofing or manipulating the positioning signal so that a device believes it is in a different location than it actually is. This technique can be used to deceive navigation systems, altering transport routes, modifying location records or even committing fraud related to deliveries or routes billed based on distance.

For example, a malicious driver could use GPS spoofing to trick a platform into believing they have traveled more kilometers than the actual ones and thus charge more, or divert transport to another area without the system detecting it immediately.

Man-in-the-Middle (MitM) Attacks

In attacks of the type Man-in-the-Middle (MitM)The cybercriminal positions themselves between two communicating parties (for example, a user and a website) and intercepts traffic without either of them noticingA common way to do this is by creating a fake Wi-Fi network with a name very similar to that of a legitimate Wi-Fi network (from a cafe, hotel, university, etc.).

If the user connects to that trap network, the attacker can capture passwords, card details, emails, and other sensitive informationIn some cases, it can also modify traffic to redirect to fake websites or inject malicious code.

Facial Spoofing

El facial spoofing It focuses on deceiving facial recognition systems. The attacker uses photographs, videos or models of another person's face in order to unlock mobile phones, access banking applications, or bypass biometric authentication controls.

If the system lacks advanced life detection mechanisms (for example, analyzing depth, natural movements, or light reflections), it can be deceived and allow unauthorized access to accounts and services very sensitive.

Spoofing in the professional and business environment

Businesses, from large corporations to SMEs, are also frequent targets of these impersonation techniques. In the professional sphere, attackers tailor their messages to impersonating bosses, colleagues, suppliers, or customers with whom the organization interacts on a daily basis.

It is common for them to try to convince employees to perform urgent payments to accounts controlled by criminalsThey may provide confidential information (customer data, internal reports, login credentials) or download documents containing malware. Many of these scams are known as CEO fraud or Business Email Compromise (BEC).

To reduce risk, it is key train the entire team in cybersecurity best practices and strengthen internal validation processes (for example, requiring double-checking for changes to supplier bank accounts or for large transfers). It also helps to have technical solutions that analyze emails, block suspicious messages, and monitor anomalous activity.

Some financial institutions offer cybersecurity services specifically for businesses, such as centralized platforms that detect and block phishing and spoofing attempts, assess the level of risk, and provide ongoing training to employees to learn how to recognize malicious communications.

Legal framework and regulatory measures against spoofing

The massive increase in spoofing-based fraud has led regulators to approve specific regulations to curb these practicesOne of the lines of action is to force telecommunications operators to strengthen controls over the numbering used in calls and SMS.

Among the most notable measures are the obligation to block communications with counterfeit, manipulated or unassigned numbers and the regulation of the identification of numbers used in customer service and sales calls. This aims to make it more difficult to use aliases or numbers that do not correspond to the actual entity.

Even so, legal and technical protection is not enough on its own: it remains essential that users Maintain a critical and prudent attitude Be wary of any communication that requests confidential information or pressures you to act urgently, especially if it arrives via SMS or phone call.

How to recognize and avoid SMS spoofing and caller ID spoofing

While no system is foolproof, there are a number of guidelines that help minimize the risk of falling victim to these scams. The first is to develop a certain “digital common sense”Be suspicious of any unexpected message or call that asks for information or that raises alarm.

When faced with a suspicious text message, the golden rule is Do not click on links included in the text and do not call the numbers that appear in the message. If it appears to be from your bank, go directly to the official website by typing the URL into your browser or access the official app, and check there if there is actually an alert or issue.

In the case of calls, even if you see the bank's number on the screen, you should not provide it. passwords, verification codes, card details, or signature keysIf they insist, hang up and call the customer service number yourself, which is listed on the official website or on the back of your card.

It is also advisable to activate and take advantage of the two-factor authentication (2FA) in critical services such as online banking, email or professional platforms, but always remembering that codes sent by SMS or to an authentication app should never be shared with anyone, even if the person claims to be from the bank.

Finally, maintain have an updated mobile phone and security solutions (antivirus, antispam, URL filters) adds an extra layer of protection against malicious apps and dangerous links, reducing the chances of infection or redirection to phishing sites.

General recommendations for protection against spoofing

Beyond each specific channel (SMS, call, email, website), there are a number of best practices that help protect against virtually any type of spoofing. One of the most important is Do not share sensitive information through insecure channels or unverified, especially if you did not initiate the communication.

In email, before clicking on a link or downloading an attachment, carefully review the sender's domain and message contentLook out for small spelling mistakes, unusual domains, or requests for information that your bank would never ask for via email. If something seems off, it's best to delete the message or contact the bank directly through another channel.

When browsing the web, get used to looking at the Full URL in the browser bar and verify that it exactly matches the entity's official address. Be wary of websites whose names are too similar to the originals but not identical, or that you received through links in unsolicited emails or text messages.

On public or open Wi-Fi networks, avoid accessing sensitive services such as online banking, corporate email, or administration panelsIf you need to do so, use a trusted VPN to encrypt the connection and reduce the chances of someone intercepting your traffic.

Finally, keep in mind that an aggressive tone or one that tries to rush you is usually a bad sign: No legitimate banking procedure requires immediate decisions under threat You could lose money in a matter of minutes. If you notice pressure or drama in the message or call, stop, take a breath, and verify the information yourself.

The combination of knowledge, healthy skepticism, and some basic technical measures makes it much more difficult for a cybercriminal to succeed with spoofing techniques, whether through SMS, calls, email, fake websites, or other digital channels.