Enumerate client configurations
Client configurations information such as the operating system and web browser, along with additional information such as version or language, are often transmitted as part of web browsing communications. This can be accomplished in several ways including use of a compromised web site to collect details on visiting computers.  
Detectable by Common Defenses (Yes/No/Partial): No
Explanation: Typical information collected as part of accessing web sites (e.g., operating system, browser version, basic configurations).
Difficulty for the Adversary
Easy for the Adversary (Yes/No): Yes
Explanation: Basic web scripting capability to collect information of interest on users of interest. Requires a compromised web site and the users of interest to navigate there.
- Joanna Geary, Chris Cross. (2012, April 13). Tracking the trackers: help us reveal the unseen world of cookies. Retrieved March 5, 2017.
- Electronic Frontier Foundation. (n.d.). Panopticlick: Is your browser safe against tracking?. Retrieved March 5, 2017.