Systems and methods of blocking phishing attempts in a computer network, including receiving a list of assets of the computer network, wherein each asset is associated with at least one computer network address, generating at least one address permutation on the at least one computer network address of each asset of the computer network, wherein the generated at least one address permutation is different from the address associated with each asset of the computer network, receiving a communication request at a gateway server of the computer network, determining a destination address of the communication request, comparing the determined destination address with the at least one address permutation, and when the determined destination address is the same as at least one address permutation, blocking the communication request at the gateway server.