How to select/filter/check security guards in IT?

Question

Personnel Management

Does anyone have experience in selecting / interviewing employees for senior positions in IT? For example, security guards and others like them. Those who have passwords, accesses and generally an understanding of the weaknesses of the entire IT economy in their hands and heads?
Please share your experience.
ps the issue of grievances / dismissal / revenge is not considered. Interested in the primary question: the selection of reliable personnel.

Answer 1

3 simple questions:
What do they know about PCI DSS?
Why can't you leave open ports accessible from the entire Internet?
How to organize access to servers (via SSH / RDP / whatever) so as not to see a sharp reduction in the staff of developers and easily audit and manage?
If a non-candidate cannot answer at least one question, with him "the probability of repelling threats is extremely small."