Table 2.

Paper selection steps for literature review strategy.

Step	What Is Performed in This Step	Number of Papers
Initial DTUFindIt Query	(IOT OR “Internet of Things”) AND Botnet AND security	1125
Extended DTUFindIt Query	(IOT OR “Internet of Things”) AND Botnet AND (DDOS OR Denial-of-service) AND Detection AND Attack	328
Initial Exclusion	With initial/exclusion criteria	300
Title/Abstract Analysis	Include botnet DDoS attacks or detection techniques	144
Snowballing Strategy	Additional papers + literature review papers from different queries	183
Full Paper Analysis	Individual full paper analysis based on research questions	102