/essential8-expert

name: essential8-expert
description: Essential 8 expert for Australian cyber security. Deep knowledge of ACSC Essential Eight mitigation strategies including 8 strategies, 3 maturity levels, implementation guidance, and Australian government requirements.
allowed-tools: Read, Glob, Grep, Write

Essential 8 Expert

Deep expertise in Australian Cyber Security Centre (ACSC) Essential Eight mitigation strategies for cyber security.

Expertise Areas

Essential Eight Overview

**Authority**: Australian Cyber Security Centre (ACSC) **Purpose**: Mitigate cyber security incidents through prioritized mitigation strategies **Structure**: 8 mitigation strategies, 3 maturity levels **Applicability**: All Australian organizations, mandatory for government **Current Version**: Updated regularly (latest guidance 2024)

**Key Principles**:

• Risk-based approach
• Prioritized mitigation strategies
• Maturity progression model
• Implementation flexibility
• Continuous improvement

**Background**:

• Based on top 35 mitigation strategies (now Strategies to Mitigate Cyber Security Incidents)
• Focused on most effective controls
• Evidence-based effectiveness (from real incidents)
• Addresses 85%+ of intrusion techniques

Maturity Levels

| Level | Name | Description | Timeline | Use Case | |-------|------|-------------|----------|----------| | **Level 1** | Partly Aligned | Basic implementation | 6-9 months | Starting point, small orgs | | **Level 2** | Mostly Aligned | Enhanced security | 9-12 months | Recommended baseline | | **Level 3** | Fully Aligned | Advanced security | 12-18 months | Government, critical infra |

**Maturity Level 1 (Partly Aligned)**:

• **Intent**: Partial protection against commodity attacks
• **Threats**: Opportunistic attackers, mass malware
• **Protection**: Basic ransomware defense, common exploits
• **Implementation**: Foundational controls
• **Validation**: Self-assessment
• **Characteristics**:
• Entry-level baseline
• Cost-effective
• Manageable operational impact
• Foundation for progression

**Maturity Level 2 (Mostly Aligned)**:

• **Intent**: Protection against sophisticated adversaries
• **Threats**: Targeted attacks, advanced persistent threats (APTs)
• **Protection**: Most attack techniques, zero-day exploitation
• **Implementation**: Enhanced controls, automation
• **Validation**: Internal assessment with external validation recommended
• **Characteristics**:
• Industry standard
• Balanced security vs usability
• Reasonable resource requirements
• Recommended for most organizations

**Maturity Level 3 (Fully Aligned)**:

• **Intent**: Maximum protection against advanced adversaries
• **Threats**: Nation-state actors, sophisticated cybercriminals
• **Protection**: Advanced techniques, zero-day, supply chain
• **Implementation**: Hardened controls, comprehensive monitoring
• **Validation**: Independent third-party assessment
• **Characteristics**:
• Highest security posture
• Significant operational controls
• Substantial resources required
• Mandatory for Commonwealth government

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The 8 Mitigation Strategies

Strategy 1: Application Control

**Purpose**: Prevent execution of unapproved/malicious programs including malware

**Risk Addressed**:

• Malware execution
• Unauthorized software
• Ransomware
• Backdoors and remote access tools

**Implementation Approach**:

• Whitelist approved applications
• Block execution from user-writable locations
• Control drivers and kernel modules
• Manage scripts and macros

Maturity Level 1 Requirements

**Workstation Controls**:

• Application control implemented on all workstations to block unapproved applications
• Microsoft's recommended application blocklist implemented
• Approved applications allowed to execute
• Application control events logged

**Technical Implementation**:

• **Windows**: AppLocker, Windows Defender Application Control (WDAC)
• **macOS**: Gatekeeper, application allowlisting
• **Linux**: AppArmor, SELinux, fapolicyd

**Allowed Execution**:

• Publisher certificate rules (preferred)
• Path rules for IT-controlled locations
• Hash rules (for unchanging apps)

**Blocked Execution**:

• User-writable directories (%TEMP%, %APPDATA%, Downloads)
• Removable media (USB drives)
• Email attachments (direct execution)

**Logging**:

• All blocked execution attempts
• Application control rule updates
• Enforcement mode changes

Maturity Level 2 Requirements

**Server Controls**:

• Application control on all servers
• Internet-facing servers prioritized
• Application control events logged centrally

**Driver/Script Controls**:

• Driver and kernel module controls
• PowerShell execution controlled (Constrained Language Mode)
• Command-line interpreters restricted
• Scripting languages blocked unless required

**Technical Additions**:

• PowerShell Constrained Language Mode
• Script execution policies enforced
• Driver signature enforcement
• Windows Defender Application Control (WDAC) policies

**Centralization**:

• Central policy management
• SIEM integration for logging
• Automated rule deployment

Maturity Level 3 Requirements

**Validation and Hardening**:

• Application control configuration validated at least annually
• Extremely hardened configuration
• Application control events analyzed for indicators of compromise
• Annual penetration testing of controls

**Advanced Capabilities**:

• Automated compliance checking
• Threat hunting using control events
• Machine learning for anomaly detection
• Integration with threat intelligence

**Testing**:

• Penetration testing of bypass techniques
• Red team exercises
• Independent validation

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Strategy 2: Patch Applications

**Purpose**: Remediate security vulnerabilities in office productivity suites, web browsers, email clients, PDF readers, Flash Player, and other applications

**Risk Addressed**:

• Exploitation of known vulnerabilities
• Zero-day attacks (limited window)
• Remote cod