SU03: Access Control and System Security

Question 1

Types of Access Control

Answer 1

1. Mandatory access control (MAC)
2. Discretionary Access Control (DAC)
3. Role-based Access Control (RBAC)

Question 2

MAC, DAC, RBAC control based on

Answer 2

1. MAC: **security labels & security clearances. **Strict; useful for army
2. DAC: subjects & access rules. Flexible, Messy. e.g. Google Docs
3. RBAC: roles subjects have & rules stating which roles can access what objects. not as flexible as DAC but easier to manage (centrally controlled)

Question 3

Types of Security threats

Answer 3

1. Intruders: hackers poise threats to OS
2. Malicious software
3. Buffer Overflow

Question 4

3 Types of Intruders

Answer 4

1. Masquerader (outsider): break system’s access control pretending to be another user
2. Misfeasor (insider): misue privilege/access resources they don’t have authorisation for
3. Clandestine (Insider/outsider): have root control of system & bypass access control

Question 5

2 Types of Malicious software

Answer 5

1. Indepedent (Worm): self-contained, self-duplicated programs. Self-duplicated, can be ran by OS
2. Co-host (Virus): parasitic, need to attach to other programs

Other examples: Trojan Horse, Ransomware

Question 6

3 occurences in Buffer Overflow

Answer 6

1. process attempts to overwrite adjacent memory location leading to programming error
2. attacker gain control in program
3. attacker use Metasploit against unpatched system & get shell remotely

Question 7

3 Countermeasures, what they do

Answer 7

1. Authentication: identify & verify users are whom they claim to be. Strengthen using 2FA
2. Access control: system to give correct access right after authentication
3. Buffer Overflow countermeasures:
   * compile-time defence: harden programs
   * Runtime defence: detect & stop attacks in executing programs

Question 8

6 Steps in Hardening OS

Answer 8

1. OS installation & patching
2. remove unnecessary services, applications, protocols
3. Configure users, groups, permissions
4. install & configure additional security controls
5. Test system secuirty

Question 9

OS installation & patching - 4 parts

Answer 9

1. proper planning of OS installation
2. minimise software package
3. take care booting process
4. use cryptographic file systems

Question 10

Remove Unnecessary services, applications, protocols

Answer 10

1. Use System planning: resolves conflict of usability and security
2. Unnecessary services shouldn’t be installed

Question 11

Configure Users, Groups, Permissions - 3 parts

Answer 11

1. do not give more access than what’s required
2. careful categorisation of groups
3. justify additional group of users

Question 12

Install & Configure Additional seucrity controls - 2 parts

Answer 12

1. Implement additional security controls (firewalls, antivirus, instrusion system)
2. update antivirus software on definition files/signarures

Question 13

test system security - 2 parts

Answer 13

1. make sure implementation works
2. depending on OS, use checklsit