Description

An adversary sends a UDP packet to a closed port on the target machine to solicit an IP Header's total length field value within the echoed 'Port Unreachable" error message. This type of behavior is useful for building a signature-base of operating system responses, particularly when error messages contain other types of information that is useful identifying specific operating system responses.

Prerequisites

The ability to monitor and interact with network communications. Access to at least one host, and the privileges to interface with the network interface card.