CompTIA A+ Operating Systems & ISC2 Risk Management

CompTIA A+ Operating Systems

Operating System Types:
- Windows
- macOS
- Linux
- Mobile OS (iOS, Android)
Windows Versions:
- Common versions: Windows 10, Windows 11
- Installations: Clean install vs. upgrade
- Features: File Explorer, Control Panel, Task Manager
Linux Basics:
- Distributions: Ubuntu, CentOS, Fedora
- Command Line: Basic commands, file permissions, package management
OS Installation & Configuration:
- System requirements
- Partitioning drives
- User account setup
System Maintenance:
- Updates: Importance of keeping systems updated
- Antivirus and Malware: Installation and configuration
- Backup strategies

ISC2 Risk Management

Risk Management Framework:
- Identify, Assess, Respond, Monitor
- Understanding assets, threats, vulnerabilities
Risk Assessment Techniques:
- Qualitative vs. Quantitative assessments
- Risk matrix: Likelihood vs. impact graph
Risk Response Strategies:
- Avoid, Transfer, Mitigate, Accept
- Development of security controls
Compliance Standards:
- Familiarity with frameworks like NIST, ISO 27001
- Regulatory requirements (HIPAA, PCI-DSS)

Reverse Engineering Techniques

Static vs. Dynamic Analysis:
- Static: Analyzing code without executing it (disassemblers, decompilers)
- Dynamic: Analyzing code during execution (debuggers)
Common Tools:
- IDA Pro: Interactive DisAssembler
- Ghidra: Open-source software reverse engineering suite
- OllyDbg: Analyzing binary programs
Process of Reverse Engineering:
- Identify executable files
- Disassemble and analyze code logic
- Document findings and reconstruct the software functionality
Legal and Ethical Considerations:
- Understanding the laws governing reverse engineering
- Ethical hacking vs. malicious attempts

ISC2 Security Concepts

Confidentiality, Integrity, Availability (CIA Triad):
- Ensuring data is accessed only by authorized users
- Maintaining data accuracy and trustworthiness
- Ensuring systems are operational when needed
Authentication vs. Authorization:
- Authentication: Verifying user identity
- Authorization: Granting permissions to users
Types of Security Controls:
- Administrative: Policies and procedures
- Technical: Firewalls, encryption, intrusion detection
- Physical: Security guards, access controls
Incident Response:
- Preparation and planning for incidents
- Steps: Detection, containment, eradication, recovery

CompTIA A+ Hardware Troubleshooting

Common Hardware Issues:
- No power: Check power supply and connections
- No boot: Inspect BIOS settings and hardware components
- Peripheral issues: Confirm device connectivity and drivers
Testing Tools:
- Multimeter: Measuring electrical parameters
- POST cards: Diagnosing boot issues
Troubleshooting Process:
- Identify the issue and gather information
- Establish a theory of probable cause
- Test the theory and implement a fix
- Document findings and follow-up actions
Preventative Maintenance:
- Regular cleaning and dusting of components
- Keeping firmware and drivers updated
- Monitoring system performance tools

Operating System Types

Windows, macOS, Linux, and Mobile OS (iOS and Android) are popular operating systems.
Windows 10 and Windows 11 are common versions of Windows.
Windows installations can either be a clean install or an upgrade from a previous version.
Common Windows features include File Explorer, Control Panel, and Task Manager.

Linux Basics

Ubuntu, CentOS, and Fedora are popular Linux distributions.
Command Line allows users to interact with the operating system using text-based commands.
File permissions control access to files and directories.
Package management allows for installing, updating, and removing software.

OS Installation & Configuration

System requirements determine what hardware is needed for installing an OS.
Partitioning drives divides the hard drive into sections for different purposes.
User accounts allow access to the system with varying privileges. Some systems require administrator accounts to manage users.

System Maintenance

Keeping systems updated with the latest patches and security fixes is important.
Antivirus and malware software protect against malicious programs.
Backup strategies help restore data in case of system failures.

ISC2 Risk Management

Risk Management Framework follows a structured approach: Identify, Assess, Respond, and Monitor.
Identifying assets, threats, and vulnerabilities are key steps in the risk management process.
Risk assessment techniques involve qualitative or quantitative approaches to evaluate risk.
Qualitative assessments rely on subjective judgment.
Quantitative assessments use numerical data to calculate risk.
Risk Matrix visually represents risk based on the likelihood and impact of a threat.
Risk Response Strategies include: Avoid (avoiding the risk altogether), Transfer (shifting the risk), Mitigate (reducing the impact), and Accept (accepting the risk without action).

Risk Assessment Techniques

Quantitative risk assessment is a formal, documented approach that uses mathematical calculations to measure risk.
Qualitative risk assessment can be performed quickly and is a useful tool for assessing various aspects of risk.

Compliance Standards

NIST, ISO 27001, and other standards provide frameworks for organizations to establish and maintain their security programs.
HIPAA and PCI-DSS are examples of regulatory requirements specific to industries like healthcare and payments.

Reverse Engineering Techniques

Static analysis examines software code without executing it. Tools used for this purpose include disassemblers and decompilers.
Dynamic analysis investigates code during execution using debuggers.
IDA Pro, Ghidra, and OllyDbg are commonly used reverse engineering tools.
Process of reverse engineering:
- Identifying files,
- Disassemblers and analyzers examine program structure and logic,
- Findings are documented to help understand the software functionality.

Legal and Ethical Considerations

Understanding legal frameworks is critical when approaching reverse engineering.
Distinguish between ethical hacking, which aims to discover vulnerabilities, and malicious attempts, which exploit vulnerabilities for personal gain.

ISC2 Security Concepts

CIA Triad (Confidentiality, Integrity, Availability) is foundational to security:
- Confidentiality: Ensuring data security and access only by authorized personnel.
- Integrity: Maintaining data accuracy and trustworthiness.
- Availability: Ensuring systems and data are available when needed.

Authentication vs. Authorization

Authentication verifies a user's identity to grant system access.
Authorization controls user access to specific resources and functions within a system.

Types of Security Controls

Administrative controls are policies and procedures that define security practices.
Technical controls employ technologies such as firewalls, encryption, and intrusion detection systems to protect data and systems.
Physical controls involve measures like security guards, access control mechanisms, and physical barriers to deter unauthorized access.

Incident Response

Incident response planning ensures a coordinated and effective reaction to security incidents.
Steps in incident response:
- Detection: Recognizing and identifying security incidents.
- Containment: Isolating and preventing further damage.
- Eradication: Removing the threat and restoring system integrity.
- Recovery: Restoring data and systems to full functionality.

CompTIA A+ Hardware Troubleshooting

Common hardware issues:
- No power: Troubleshooting includes checking the power supply and connections.
- No boot: Inspect BIOS settings and diagnose potential hardware malfunctions.
- Peripheral issues: Verify device connectivity and install proper drivers.

Testing Tools For Hardware Troubleshooting

Multimeter: Measures electrical parameters such as voltage and resistance.
POST cards: Display codes during the boot process, providing clues about hardware issues.

Troubleshooting Process

Identify the issue: Gather pertinent information, including error messages and symptoms.
Establish a theory of probable cause: Analyze the symptoms and research potential solutions.
Test the theory to implement a fix: Apply the solution and verify if it resolves the problem.
Document findings: Record details of the troubleshooting process and solutions for future reference.

Preventative Maintenance for Hardware

Regular cleaning and dusting: Removes accumulated dust that can cause overheating and malfunctions.
Keeping firmware and drivers updated: Ensures compatibility and optimal performance.
Monitoring system performance tools: Helps identify potential issues and proactively address them.