Open Source & Passive Information Gathering

[Resheph]

As far as intelligence gathering goes, open source or passive information gathering is the least aggressive. Basically the process relies on obtaining information from those sources that are typically publicly available and out in the open. Potential sources include newspapers, websites, discussion groups, press releases, television, social networking, blogs, and innumerable other sources.
With a skilled and careful hand, it is more than possible to gather operation system and network information, public IP addresses, web server information, and TCP & UDP data sources, and a whole lot more.