GROUP 267 members, 17 online · Security; the entity's title ISDEF which stands for Israel's Defense establishment & Defense companies

GROUP 821 members, 49 online · Security & Defense. This matches with Ethical Hacking & Cybersecurity

GROUP 122 members · Your prompt is missing the actual content to analyze. It only contains a comment with "system". However, assuming the missing content contains a topic related to computer systems or programming, I'd select: Technology & Programming If the content is more about defense or protection from hacking, I'd select: Ethical Hacking & Cybersecurity

GROUP 2 950 members, 25 online · Defense & Fitness / Military