Secure Architecture

Question 1

Threat Modelling

Answer 1

A team exercise undertaken to identify and mitigate threats. Typically planned early in the lifecycle. Steps:
1. Identify Security Objectives: Legal, compliance requirements.
2. System Decomposition: Data Flow diagrams (Consider data stores, function calls, trust boundaries [VMs, user privileges, networks]).
3. Threat Identification: DFD creation may identify threats. STRIDE is another way.
4. Threat Mitigation: Strategies - Re-design to mitigate (most preferred), apply std mitigation, invent a new mitigation (costly and time consuming), accept and ignore. Use Attack Tree model.

Question 2

Threat Modeling - STRIDE for threat identification.

Answer 2

Spoofing (Authentication),
Tampering (Integrity),
Repudiation (non-Repudiation),
Information Disclosure (Confidentiality),
Denial of Service ( Availability),
Escalation of privilege (Authorization).

Question 3

Threat Modeling - Threat Mitigation - Attack tree

Answer 3

An attack tree is a graphical representation of an attack, beginning with the attack objective as the root node. From this node, a hierarchical tree-like structure of necessary conditions is listed.

Question 4

Threat Modeling - Threat Mitigation - Assessing Priority-How?

Answer 4

1. Multiply probability with Risk/loss.
2. DREAD - Damage Potential, Reproducibility, Exploitability, Affected Users and Discoverability. Assign 0 to 5 for each, sum and divide by 5 to arrive at a score from 0 to 10.

Question 5

Attack Surface Evaluation and minimization

Answer 5

Determined by all the features implemented. Measured by Attack Surface Quotient (ASQ). Disabling unused features, minimizing privileges, env hardening helps. Evaluation happens as the product is updated, typically undertaken during Design phase to avoid rework later.

Question 6

Threat Intelligence

Answer 6

Threat intelligence is the actionable information about malicious actors, their tools, infrastructure, and methods.

Question 7

Threat Hunting

Answer 7

An iterative process of proactively searching out threats inside the network, typically by forming hypothesis and testing them. E.g. “an adversary is using stolen credentials to mimic authorized users during nonworking hours.”. Verify logs to check if this true.

Question 8

Security Controls

Answer 8

Classes: Administrative, Technical and Physical
For each Class 4 Types: Preventive, Detective, Corrective, Compensating

Question 9

NIST Special Publication 800-145

Answer 9

The NIST Definition of Cloud Computing

Question 10

Trusted Platform Module (TPM)

Answer 10

A chip exists on motherboard, includes a unique RSA key burned into it, which is used for asymmetric encryption. Additionally, it can generate, store, and protect other keys used in the encryption and decryption process.

Question 11

Hardware Security Module

Answer 11

Typically attached via USB or network connections used to manage and store cryptographic keys.

Question 12

OCTAVE model

Answer 12

Operational Critical Threat, Asset and Vulnerability Evaluation

Question 13

PASTA

Answer 13

Process for Attack simulation and Threat Analysis

Question 14

NIST SP 800 30

Answer 14

Has a list of threats in its appendices