A method is provided for transmitting voice
phishing notification information to a user using multiple communication media while the mother app is deactivated. The method comprises the steps of: transmitting information regarding a new app of the electronic device to a
server of an in-app embedded in the mother app in the form of a
library while the mother app installed on the electronic device is deactivated; receiving voice
phishing notification information generated from the
server of the mother app based on detection information that the new app is a malicious app; and outputting the voice
phishing notification information while the mother app is deactivated, wherein the voice phishing notification information may be received through at least one communication medium among a
text message, a
social network service (SNS) message, a telephone, and an email.