Access control lists

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. What does an access control list (ACL) attached to a file do?

A Lists which users or groups may access the file and what they can do

B Scans the file for viruses and removes them

2. A file share has this ACL row: Maya | Read. Which action can Maya do?

A Open and read the files

B Edit and delete the files

3. Jordan is not listed anywhere in the ACL of a shared folder. What happens when Jordan tries to open it?

A Access is allowed because nobody blocked Jordan

B Access is denied

4. An ACL row reads: Year10Students | Read, Write. Who does this row apply to?

A A whole group called Year10Students

B Only one single student

5. Which of these is a place where an ACL is commonly used?

A A keyboard deciding which letters to type

B A router deciding which devices can reach a network

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1alice: read, write		AAccess is denied by default. A user who is not listed in the ACL cannot open the folder.
2Everyone: no access		BOne row of an ACL: the user alice is allowed to read and write this resource.
3An ACL on a file share can give a group read-only access to a folder.		Cpermit 192.168.1.10 deny all
4An ACL on a network device such as a router lists which addresses are allowed in.		DA rule that denies access to all users. Anyone not given permission by another row is blocked.
5Folder: Payroll Sam: read Sam is not listed so Sam can still open it		EAn ACL is attached to the resource, not the user. It lists who can access that one resource.
6An ACL is stored on each user's phone and lists every file they have		FFolder: Reports Students: read Teachers: read, write

Definitions

access control list (ACL)

Fill in the Blanks

Complete each line of code by filling in the missing parts.

ACL: staff -> read, write ACL: students -> read Everyone else -> ____

# mia can view the file but not change it mia -> ____

___ for share Homework: Year9 -> read, write Year10 -> read

router ACL: ______ 192.168.1.10 deny any

router ACL: permit 192.168.1.10 deny ___

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A # Students may only read marks

B teachers: read, write

C students: read, write

D default: deny

Question 2

A Router ACL (checked top down)

B permit 10.0.0.5 to server

C permit 10.0.0.6 to server

D permit all

Question 3

A user: Budget.docx

B finance: read, write

C interns: read

D default: deny

Question 4

A user ← Mia

B IF user is not in the ACL THEN

C allow listed actions

D ELSE deny

Question 5

A Row: maya, read-only

B Request: maya reads file

C Result: deny

D Request: maya edits file

E Result: deny

Answer Key

Access control lists

Section A: Quick Questions

A — Lists which users or groups may access the file and what they can do

A — Open and read the files

B — Access is denied

A — A whole group called Year10Students

B — A router deciding which devices can reach a network

Section B: Match the Pairs

alice: read, write → One row of an ACL: the user alice is allowed to read and write this resource.

Everyone: no access → A rule that denies access to all users. Anyone not given permission by another row is blocked.

An ACL on a file share can give a group read-only access to a folder. → Folder: Reports Students: read Teachers: read, write

An ACL on a network device such as a router lists which addresses are allowed in. → permit 192.168.1.10 deny all

Folder: Payroll Sam: read Sam is not listed so Sam can still open it → Access is denied by default. A user who is not listed in the ACL cannot open the folder.

An ACL is stored on each user's phone and lists every file they have → An ACL is attached to the resource, not the user. It lists who can access that one resource.

Section C: Definitions

access control list (ACL) — A table attached to a resource, like a file or router, that lists which users or groups may access it and what they can do. If you are not listed, access is denied.

Section D: Fill in the Blanks

ACL: staff -> read, write
ACL: students -> read
Everyone else -> deny

# mia can view the file but not change it
mia -> read

ACL for share Homework:
  Year9 -> read, write
  Year10 -> read

router ACL:
  permit 192.168.1.10
  deny any

router ACL:
  permit 192.168.1.10
  deny any

Section E: Spot the Error

C — The comment says students may only read the marks file, so their row must list just read. Giving them write lets them change marks. It should be students: read.

D — An ACL should deny by default. Only the listed devices should be permitted, and everything else should hit the final rule, deny all. Writing permit all lets anyone through.

A — An ACL is attached to a resource, so the first line should name the resource (resource: Budget.docx). Budget.docx is a file, not a user.

B — Only users who ARE listed in the ACL get the actions listed for them. The test should be IF user is in the ACL THEN, with ELSE deny for everyone else.

C — Maya's row lists read, so her request to read the file is allowed. The result should be allow. Her edit request on line 5 is correctly denied.