The Department of Telecom on Thursday issued an advisory to users warning against malicious calls that ask them to dial '*401#' followed by an unknown mobile number.

In case a user dials '*401#' followed by an unknown number, then it leads to activation of unconditional call forwarding received on the mobile of the user to the unknown mobile number.

"The Department has advised citizens to beware of receiving malicious incoming calls asking them to dial *401# followed by some unknown mobile number.

"This activates unconditional call forwarding received on the mobile of citizens to the unknown mobile number. This allows fraudsters to receive all incoming calls and can be used for fraud," the statement said.

Explaining the modus operandi of the scam, the DoT said a fraudster will call a telecom subscriber and pretend to be a customer service representative or technical support staff from their telecom service provider.

The fraudster then states that either there is a problem with their SIM card or there is some issue related to network or service quality. Then, the subscriber is asked to dial a specific code to fix the problem. The code usually starts with '*401#' followed by a mobile number. Once that is done, unconditional call forwarding is activated on the mobile number concerned, it said.

The DoT said that telecom service providers never ask their subscribers to dial '*401#' and advised citizens to check their mobile phone settings for call forwarding and disable immediately in case call forwarding has been enabled by way of dialling '*401#'

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