> For the complete documentation index, see [llms.txt](https://wiki.zacheller.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.zacheller.dev/network-security/courses/isci-cnss-course/operating-system-hardening.md).

# Operating System Hardening

What minimum password length does the NSA recommends?

> 12

Which of the following best describes the registry

> A database containing system settings

What account lockout threshold does the NSA recommend?

> 3 tries

What maximum password age does Microsoft recommend?

> 42 days

The command `sudo find / -perm -4000` checks for the location of suid binaries

> True

What level of privileges must all users have?

> Least possible

What is the rule for unused services on any computer?

> Turn them off

A Linux system has a repository of packages available to be installed on the system

> True

What type of encryption does EFS utilize?

> Public key encryption 
>
> EFS uses **symmetric key** encryption in combination with public key technology to protect files

What operating system require periodic patches?

> All