Acs_lec1

• Computer security


  The protection of the assets of a computer system
• Assets of a computer system

  • Hardware
  • Software
  • Data
• Hardware assets


  • Computer
  • Devices (disk drives, memory, printer)
  • Network gear
• Software assets


  • Operating system
  • Utilities (antivirus)
  • Commercial applications (word processing, photo editing)
  • Individual applications
• Value of assets


  • Off the shelf; easily replaceable
  • Unique; irreplaceable
• Cyber security


  The practice of defending computers, servers, mobile devices, electronic systems, networks and data from malicious attacks
• Vulnerability


  A weakness in the system that might be exploited to cause loss or harm
• Threat


  A set of circumstances that has the potential to cause loss or harm
• Attack


  A human or another machine which exploits a vulnerability to perpetrate an attack on the system
• Countermeasure or control


  An action, device, procedure, or technique that removes or reduces a vulnerability
• Threat


  • Vulnerability
  • Control
• Confidentiality


  The ability of a system to ensure that an asset is viewed only by authorized parties
• Integrity


  The ability of a system to ensure that an asset is modified only by authorized parties
• Availability


  The ability of a system to ensure that an asset can be used by any authorized parties
• Authentication


  The ability of a system to confirm the identity of a sender
• Nonrepudiation (Accountability)


  The ability of a system to confirm that a sender cannot convincingly deny having sent something
• Access control policy


  Who + What + How = Yes/No
• Types of threats


  • Natural causes
  • Benign intent
  • Malicious intent
• Examples of threats


  • Fire, power failure
  • Human error
  • Impersonation
  • Malicious code on a general web site
• Advanced Persistent Threat (APT)


  Organized, directed, well financed, patient, silent
• Types of attackers


  • Criminal-for-hire
  • Organized crime member
  • Individual hacker
  • Terrorist
  • Loosely connected group
• Types of harm


  • Modification
  • Fabrication
  • Interruption
  • Interception
• Method-Opportunity-Motive

  • Opportunity
  • Motive
  • Method
• Confidentiality, integrity, availability


  Technical, procedural, physical controls protect against different types of threats
• Different types of controls

  • Technical
  • Procedural
  • Physical