A method and system for preventing the detection of an operating system by an intruder, the operating system installed on a host in a network, is provided. The intruder transmits a network probe for operating system detection. The network probe is identified and a response is generated to the network probe, generated by the operating system, is modified. The modified response provides the intruder with false information related to the operating system, thereby misleading the intruder about the type of operating system.