U2.1 Comp Sec: deals with prevention & detection of unauthorised actions by users of a comp system

U2.1 Comp Sec: deals with prevention & detection of unauthorised actions by users of a comp system

1. Accountability & Authorisation

   • Accountability closely related to detection
     • Keep audit trails and logs protected so actions affecting Sec can be traced to those responsible
   • Authorisation related to prevention
     • Users must be identified and authorised, usernames / passwords

2. Confidentiality

   • Prevent unauthorised disclosure
     • Stop unauthorised viewing
       • Prevention more important than detecting or reacting
     • Cant recover from a breach of confidentiality
   • Privacy
     • Protecting personal data
   • Secrecy
     • Protecting organisational secrets

3. Integrity

   • Prevent unauthorised modification
     • Internal Consistency
       • Clark & Wilson
         • No user of a system even if authorised may be permitted to modify data in a way that assets or accounting records are lost /corrupted
     • External consistency
       • Orange Book
         • data has not been exposed to to accidental or malicious alteration or destruction
     • Detection of intentional / accidental modifications
   • A prerequisite for many security services

4. Availability

   • Prevent unauthorised withholding of information / resources
   • May be the most important aspect of Comp Sec
   • DDOS

5. Prevention

   • Measures to prevent damage

6. Detection

   • Detecting when, how & who did damage
     • Maintaining the integrity

7. Reaction

   • Recovery from damage

8. Reliability & dependability

   • Making systems dependable
     • Extremley important in safety critical systems, national infrastructure