Operating System Configuration: Operating System Configuration involves adjusting system settings and hardening the default configurations of an operating system (OS) to mitigate adversary exploitation and prevent abuse of system functionality. Proper OS configurations address security vulnerabilities, limit attack surfaces, and ensure robust defense against a wide range of techniques. This mitigation can be implemented through the following measures:
Disable Unused Features:
- Turn off SMBv1, LLMNR, and NetBIOS where not needed.
- Disable remote registry and unnecessary services.
Enforce OS-level Protections:
- Enable Data Execution Prevention (DEP), Address Space Layout Randomization (ASLR), and Control Flow Guard (CFG) on Windows.
- Use AppArmor or SELinux on Linux for mandatory access controls.
Secure Access Settings:
- Enable User Account Control (UAC) for Windows.
- Restrict root/sudo access on Linux/macOS and enforce strong permissions using sudoers files.
File System Hardening:
- Implement least-privilege access for critical files and system directories.
- Audit permissions regularly using tools like icacls (Windows) or getfacl/chmod (Linux/macOS).
Secure Remote Access:
- Restrict RDP, SSH, and VNC to authorized IPs using firewall rules.
- Enable NLA for RDP and enforce strong password/lockout policies.
Harden Boot Configurations:
- Enable Secure Boot and enforce UEFI/BIOS password protection.
- Use BitLocker or LUKS to encrypt boot drives.
Regular Audits:
- Periodically audit OS configurations using tools like CIS Benchmarks or SCAP tools.
Tools for Implementation
Windows:
- Microsoft Group Policy Objects (GPO): Centrally enforce OS security settings.
- Windows Defender Exploit Guard: Built-in OS protection against exploits.
- CIS-CAT Pro: Audit Windows security configurations based on CIS Benchmarks.
Linux/macOS:
- AppArmor/SELinux: Enforce mandatory access controls.
- Lynis: Perform comprehensive security audits.
- SCAP Security Guide: Automate configuration hardening using Security Content Automation Protocol.
Cross-Platform:
- Ansible or Chef/Puppet: Automate configuration hardening at scale.
- OpenSCAP: Perform compliance and configuration checks.
User Account Management: User Account Management involves implementing and enforcing policies for the lifecycle of user accounts, including creation, modification, and deactivation. Proper account management reduces the attack surface by limiting unauthorized access, managing account privileges, and ensuring accounts are used according to organizational policies. This mitigation can be implemented through the following measures:
Enforcing the Principle of Least Privilege
- Implementation: Assign users only the minimum permissions required to perform their job functions. Regularly audit accounts to ensure no excess permissions are granted.
- Use Case: Reduces the risk of privilege escalation by ensuring accounts cannot perform unauthorized actions.
Implementing Strong Password Policies
- Implementation: Enforce password complexity requirements (e.g., length, character types). Require password expiration every 90 days and disallow password reuse.
- Use Case: Prevents adversaries from gaining unauthorized access through password guessing or brute force attacks.
Managing Dormant and Orphaned Accounts
- Implementation: Implement automated workflows to disable accounts after a set period of inactivity (e.g., 30 days). Remove orphaned accounts (e.g., accounts without an assigned owner) during regular account audits.
- Use Case: Eliminates dormant accounts that could be exploited by attackers.
Account Lockout Policies
- Implementation: Configure account lockout thresholds (e.g., lock accounts after five failed login attempts). Set lockout durations to a minimum of 15 minutes.
- Use Case: Mitigates automated attack techniques that rely on repeated login attempts.
Multi-Factor Authentication (MFA) for High-Risk Accounts
- Implementation: Require MFA for all administrative accounts and high-risk users. Use MFA mechanisms like hardware tokens, authenticator apps, or biometrics.
- Use Case: Prevents unauthorized access, even if credentials are stolen.
Restricting Interactive Logins
- Implementation: Restrict interactive logins for privileged accounts to specific secure systems or management consoles. Use group policies to enforce logon restrictions.
- Use Case: Protects sensitive accounts from misuse or exploitation.
Tools for Implementation
Built-in Tools:
- Microsoft Active Directory (AD): Centralized account management and RBAC enforcement.
- Group Policy Object (GPO): Enforce password policies, logon restrictions, and account lockout policies.
Identity and Access Management (IAM) Tools:
- Okta: Centralized user provisioning, MFA, and SSO integration.
- Microsoft Azure Active Directory: Provides advanced account lifecycle management, role-based access, and conditional access policies.
Privileged Account Management (PAM):
- CyberArk, BeyondTrust, Thycotic: Manage and monitor privileged account usage, enforce session recording, and JIT access.