ISO 27033 Lead Manager flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Defence in depth

Layering independent controls across perimeter, network segments, hosts, applications and data so that failure of one control does not directly expose the protected asset.

Trust boundary

A point in the architecture where the required level of protection changes, so every crossing must be mediated by an identified control such as a filter or authenticated gateway.

Default deny

The rule that traffic and access are refused unless explicitly permitted by a documented rule. It is the operational form of least privilege in network configuration.

Risk versus vulnerability

A vulnerability is a weakness that a threat could exploit; risk combines the likelihood of that exploitation with the resulting impact on assets and business objectives.

Residual risk acceptance

Risk remaining after controls are applied must be formally accepted by the accountable business owner, not silently carried by technical staff who implemented the controls.

Separation of duties

Dividing critical tasks, such as rule authoring, approval and implementation, among different people so no single individual can compromise a control unnoticed.

Security domain

A set of assets, systems and users subject to the same security policy and protection requirements, typically implemented as a network zone with controlled boundaries.

Security lifecycle

The progression from requirements and design through implementation, operation, monitoring, review, maintenance and decommissioning, each stage requiring continuing security attention.

ISO/IEC 27033-1 scope

Part 1 provides the overview and concepts of the series: terminology, security architecture design process, threats and risks, and guidance on identifying and selecting controls.

ISO/IEC 27033-2 content

Part 2 addresses network security architecture and design, describing the design process, architecture definition and the identification of controls for planned or existing networks.

ISO/IEC 27033-3 content

Part 3 presents reference networking scenarios and, for each, the associated risks, threats, design techniques and control issues, supporting practical architecture decisions.

ISO/IEC 27033-4 content

Part 4 covers securing communications between networks using security gateways, including gateway selection, placement and the controls applied to inter-network traffic.

ISO/IEC 27033-5 content

Part 5 addresses virtual private networks, covering how VPNs are used to secure connections across untrusted networks and the related design and control considerations.

ISO/IEC 27033-6 content

Part 6 covers wireless and IP-based mobile network access, addressing the risks and controls for connecting devices over wireless and mobile technologies.

27001 versus 27033

ISO/IEC 27001 states certifiable requirements for an information security management system; ISO/IEC 27033 supplies supporting guidance on how to implement network security within it.

27002 versus 27033

ISO/IEC 27002 provides the general control catalogue; ISO/IEC 27033 elaborates network-specific architecture, design and scenario guidance for the network-related controls.

Architecture versus design

Architecture is the high-level, long-lived arrangement of zones, trust boundaries and control principles; design is the concrete technical realisation using specific products and configurations.

Network security architecture design process

Define scope and assets, identify threats and risks, derive security requirements, select and place controls, document the architecture, then verify and maintain it over time.

DMZ segmentation

Externally reachable services are placed in a separate zone with filtered, logged paths and no direct uncontrolled route into internal zones holding sensitive systems.

Network zoning rule

Group assets with identical protection requirements into one zone and place a mediating, logging control at every boundary; uncontrolled transitive paths between zones are prohibited.

Data flow analysis

Identifying what data crosses which links and boundaries, between which zones, at what sensitivity, to determine where protection and monitoring controls are required.

Threat modelling

Systematically enumerating threats against a proposed or existing network design to identify where controls are missing and to prioritise architecture changes before implementation.

Availability as design objective

Resilience, redundancy, failover and capacity are security requirements; denial of service and single points of failure must be treated as design risks, not operational afterthoughts.

Remote access design decisions

Remote and third-party links require explicit choices on authentication strength, encryption, endpoint trust and precisely which internal resources the remote device may reach.

Control placement rationale

Documented architecture records why each control sits at a given boundary, so later changes can be assessed against the original risk reasoning and requirements.

Design verification

Design review, threat modelling, configuration review and testing confirm the implemented network matches the approved architecture; deviations are risk-assessed and recorded.

Firewall rule hygiene

Every rule has an owner, stated purpose and review date; rule sets end in default deny; unused or overly broad rules are removed on a defined cycle.

Logging requirements

Network logs need time synchronisation, protected storage, retention matching legal and forensic needs, and defined review frequency with escalation thresholds for anomalies.

Monitoring layers

Detection combines log collection and correlation, flow analysis, intrusion detection alerts, availability and performance monitoring, and integrity checks on configurations.

Incident handling lifecycle

Preparation, detection and analysis, containment, eradication, recovery, and post-incident lessons learned, with findings fed back into architecture and control selection.

Baseline for detection

Documented normal traffic patterns, expected rule hits and known topology make anomalies meaningful; without baselines, monitoring produces alerts that cannot be interpreted.

Network containment actions

Isolating affected segments, preserving evidence such as logs and flow records, coordinating communication, and returning systems to service under controlled, verified conditions.