Mobile phone numbers have become central to a customer’s digital identity, particularly for banking services, transaction alerts, one-time passwords and other confidential communications. Fraudsters can exploit this dependence through SIM swap fraud, a form of account takeover in which criminals obtain control of a victim’s mobile number and use it to access sensitive banking information.
How SIM Swap Fraud Works
SIM swap fraud occurs when criminals obtain a duplicate SIM card from a telecom operator using a victim’s mobile number. Fraudsters may approach telecom representatives under false pretences, claim that the original handset or SIM card has been lost or damaged, or request that the number be ported to a new SIM.
The fraud may involve fake documents or collusion with representatives of a telecom operator. Once the duplicate SIM is activated, calls, text messages and banking alerts intended for the genuine customer may be diverted to the fraudster.
Before seeking a replacement SIM, criminals may collect the victim’s mobile number and banking details through phishing, vishing, Trojan or malware attacks and social engineering. These details can then be combined with control of the mobile number to gain access to the victim’s account.
What Criminals Can Do After Taking Control
After obtaining the duplicate SIM and stolen banking credentials, fraudsters may access and operate the victim’s bank account. They can initiate financial transactions while the customer remains unaware because transaction messages, payment confirmations, security codes and other alerts are delivered to the fraudster-controlled SIM.
A sudden and prolonged loss of mobile network connectivity can therefore be a warning sign. Customers who stop receiving calls or text messages without explanation should immediately contact their telecom service provider and verify whether any replacement or porting request has been processed.
Suspicious bulk notifications from a network provider should also not be ignored, particularly messages indicating a possible SIM swap. Customers should verify such alerts directly with their telecom operator rather than relying on information provided by an unknown caller.
Precautions That Can Reduce the Risk
Precautions That Can Reduce the Risk:
- Customers can lower the risk of SIM swap fraud by following these precautions:
- Contact the telecom operator immediately if mobile network connectivity disappears unexpectedly for an unusually long period.
- Verify the status of the SIM directly with the telecom service provider instead of trusting an unknown caller.
- Do not ignore suspicious bulk messages or notifications warning about a possible SIM replacement or porting request.
- Never click unverified links received through SMS, email or messaging applications.
- Do not share Aadhaar details, SIM information, banking credentials, one-time passwords or other confidential information with unknown callers.
- Be cautious if numerous unfamiliar calls are received in a short period, especially if callers ask you to switch off the phone.
- Register for instant banking alerts through both SMS and email.
- Check bank statements regularly and report any unauthorised or unusual transaction immediately.
- Set suitable upper withdrawal and transaction limits for banking activity.
- Immediately inform the bank and block affected accounts if SIM swap fraud or unauthorised access is suspected.
