Security Controls , CIA , Non-repudiation , AAA

Preventive

Stops an incident before it happens (e.g., firewall, locks)

Detective

Identifies an incident while or after it happens (e.g., SIEM alerts, motion sensors).

Corrective

Fixes or restores systems after an incident (e.g., restoring from a backup, patching).

Compensating

A workaround used when primary controls can't be met (e.g., IP whitelisting when MFA isn't supported).

Deterrent vs. Directive Controls

• Deterrent: Discourages an attacker from trying (e.g., warning signs, bright lighting).

• Directive: Mandates specific behavior or rules for personnel (e.g., mandatory policy training, acceptable use rules).

The CIA Triad

• Confidentiality: Keeping data hidden from unauthorized eyes (encryption, access controls).

• Integrity: Ensuring data hasn't been unauthorizedly altered or corrupted (hashing, digital signatures).

• Availability: Ensuring systems and data are accessible to authorized users when needed (redundancy, high availability).

What is Non-repudiation?

A cryptographic property (achieved via digital signatures) that proves a sender cannot deny having sent a message or initiated an action.

AAA Framework

• Authentication: Proving who you are (username/password, MFA).

• Authorization: What you are allowed to access once logged in (permissions, privileges).

• Accounting: Logging and tracking resource usage, session duration, and user actions.