Summarize how each of the three tailored file security policies changes the access rights of files under the two default security policies
- Privacy: Overrides a global file sharing policy
- Shared Reading: Overrides a global isolation policy
- Shared Updating: Overrides either global policy
When tailoring, we answer 4 questions:
- Which resources are we managing
- Which users have access
- Deny by default or modify the existing rights
- What access rights do nonowners have
Problem of admins logged in as root:
the system couldn’t tell which admin performed a particular task
With Unix “SUDO” and “SetUID” commands, what privileged operation can the user do?
The user can execute a privileged operation as “root”
Admin roles are dangerous, since admins can accidentally execute Trojan horses and other malware in “root,” what are safe alternatives for this?
Temporary rights (UAC), and having two User IDs: a regular user ID that has no special privileges and one special user ID with administrative privileges.
What are three sets of RWX flags?
- Owner rights (u)
- Group rights (g)
- World rights (o)
What is ACL?
Access Control Lists are a general-purpose technique that cluster access rights by row.
How do you build an effective ACL?
- Deny by Default is the best general approach
- start with no rights, or a small set of defaults- permissions to owner and administrators
- add allow rights as needed
- permissions to owner and administrators
- Keep the rules as simple as possible
In Windows ACL, permissions are applied in a specific order:
- Permissions specifically assigned to that file or directory are applied first
- Next, apply those inherited from the enclosing directory
- If more permissions inherited, apply them in inheritance order; most recent to least recent
Describe the behavior of “sudo” on Unix. When is “sudo” used?
On Unix, sudo is a prepackaged function that runs setuid with the identity of root. It’s used when administrators need to perform serious system changes, allowing them to run programs as root after authenticating with the correct password, without logging in as the root account directly.
When we create a file, explain how that file acquires its initial ACL under Windows.
In Windows, when we create a new file, it simply inherits access rights from the folder in which we save the file.
This is called dyamic ACLs that inherit access rights from the enclosing folder. Files use the “parent” ACL, which is retrieved from their folder.
If we change the ACL for a folder under Windows, what typically happens to the ACLs for the files within that folder?
If we change the ACL for a folder in Windows, the files inside also change their ACLs—as long as they inherit permissions from the folder.
