Methods, systems, and devices are provided for inquiring and storing Indicator of Compromise (IoC) information. In one example, a method of inquiring and storing IoC information can include determining a target IoC information to be identified when an event occurs, requesting an encryption socket communication module of a first user terminal to request the target IoC information from an IoC information providing server, requesting a P2P socket communication module of the first user terminal to request the target IoC information from a P2P socket communication module of at least one other user terminal, and storing the target IoC information that is received first from either the IoC information providing server or the P2P socket communication module of the at least one other user terminal.