CHENNAI: The Cyber Crime Wing of Tamil Nadu police has issued an alert regarding an emerging cyber fraud wherein criminals impersonate courier or delivery service agents to fraudulently access citizens' bank accounts and social media platforms.

Explaining the modus operandi, the police stated that cybercriminals contact individuals claiming to confirm or reschedule a parcel delivery.

"During the conversation, victims are instructed to dial a Unstructured Supplementary Service Data (USSD) code received via SMS, typically beginning with 21 followed by a mobile number that belongs to the fraudster. Dialling this code enables call forwarding on the victim's mobile phone without their knowledge," an official release explained.

Once call forwarding is activated, all incoming calls including bank verification calls, OTP confirmations, and authentication calls from WhatsApp or Telegram are automatically diverted to the fraudsters. This allows criminals to carry out unauthorised financial transactions and take over messaging accounts.

ADGP Sandeep Mittal, head of State Cyber Crime Wing, appealed to the public to share the advisory among friends and families.

What is USSD?

Unstructured Supplementary Service Data is a communication protocol that allows mobile phones to interact directly with a service provider's systems using short codes like *12

Advisory to public

Never dial USSD codes such as 21, 61, 67, or similar codes shared by unknown callers

Do not trust unsolicited calls claiming to be from courier or delivery companies

Avoid clicking suspicious delivery links received via SMS, WhatsApp, or email

Verify delivery details only through official courier websites or customer care numbers

If call forwarding is activated unknowingly, dial##002 immediately to cancel all call forwarding services