Bank transaction occurred without an OTP? Understand this method, which is different from SIM Swap

How can a bank transaction take place without an OTP? Learn about a fraud method—distinct from SIM Swap—whereby money can be withdrawn from a bank account even without an OTP.

An OTP is considered the most essential security safeguard for bank accounts. But what if a transaction occurs on your bank account without any OTP ever reaching your phone? In such a scenario, it is incorrect to attribute the incident solely to SIM Swap; cybercriminals can execute banking fraud using various other methods.

How can a transaction happen without an OTP?

It is important to note that an SMS OTP is not mandatory for every online banking transaction. Many banks and payment services employ different authentication systems based on risk assessment. For instance, payments can be completed using pre-saved beneficiaries, trusted devices, app-based approvals, or a UPI PIN.

This means that if an attacker gains access to your banking app or obtains the necessary UPI-related information, they do not necessarily need an SMS OTP for every transaction.

What is the method other than SIM Swap?

For your information, in a SIM Swap attack, the criminal typically attempts to obtain a new SIM card for your number through the mobile operator. Consequently, SMS messages and calls intended for your number are diverted to them.

However, another threat involves unauthorized access to your mobile or banking app account. If a malicious app is installed on your phone, banking credentials are stolen, or someone gains access to your device, a criminal can execute certain types of transactions without even intercepting the OTP.

No OTP required for UPI fraud

UPI payments serve as the simplest example of this. Standard UPI transactions utilize a UPI PIN rather than an SMS OTP. If a criminal somehow discovers your UPI PIN and gains access to your UPI app or device, they can attempt to transfer money from your account.

For this reason, relying solely on SMS OTPs for security is not sufficient. The security of your UPI PIN, phone screen lock, and banking apps is equally important.

Malware can also pose a major threat

Suspicious or malicious apps on your phone can pave the way for banking fraud. Some malware may obtain accessibility permissions from the user to read on-screen information or interact with other apps.

Exercise caution if you have recently downloaded an APK from an unknown website or granted permissions—such as Accessibility, SMS, Notification, or Screen Overlay—to a suspicious app.

Do not ignore banking alerts

If you receive a transaction alert from your bank but did not receive an OTP, treat the matter seriously and immediately. First, check your account via the bank’s official app or website, and if necessary, temporarily block your card, UPI, or net banking services. Instead of relying on links or numbers provided in SMS messages, WhatsApp messages, or calls, use the bank’s official customer care number.

Take these precautions with your phone

Install only trusted apps on your phone and avoid unknown APKs. Use strong passcodes for banking apps, UPI apps, and email accounts. Do not share your OTP, UPI PIN, card PIN, or internet banking password with anyone.

Most importantly, the fact that you did not receive an OTP is not proof that your bank account is secure. If you notice any unfamiliar transaction, the most crucial step is to inform the bank immediately.