Network scanners are a valuable resource in the security practitioner.s toolkit. They are used to actively probe a network in order to generate a snapshot of the current environment. However, they are not without limitations; they can be loud, resource intensive, and the results can be quickly outdated. During this presentation I will discuss how a passive scanner can be used to identify network traffic.

Passive Asset Detection System (PADS) was designed to supplement active scanners by combining a network sniffer with a rule-based detection engine similar to a network IDS. It will listen to a network and attempt to provide an up-to-date look at the hosts and services running on the network. The application operates invisibly and will never release a packet into the network.