The article is devoted to the description of the method of forming steganographic network messages using the ICMP service protocol for their hidden transfer, bypassing restrictions of firewalls and other computer network protection systems. It describes the functions of the ICMP protocol, its advantages when used in steganography tasks, and the specifics of processing ICMP packets by operating systems and intermediate network equipment. Special attention is paid to the practical implementation and application of the proposed method. It describes the network utilities for working with packages and an example of their use for transmitting a hidden message. For the software implementation of the network steganography method, it is proposed to use the C # programming language and the SharpPCap and Packet.NET libraries, for which the article contains examples of use and the necessary parameters for forming packets with steganographic messages.
Keywords: information security, network steganography, ICMP protocol, TCP / IP stack, encapsulation, SharpPCap